Adds back the now generic Fate computation (lambda stuff still to be done).

34 files changed, 5075 insertions, 137 deletions

diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/Access.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/Access.java
new file mode 100644
index 0000000..11ff4d1
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/Access.java
@@ -0,0 +1,166 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+
+import tonkadur.error.ErrorManager;
+
+import tonkadur.fate.v1.error.InvalidTypeException;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.type.CollectionType;
+import tonkadur.fate.v1.lang.type.PointerType;
+import tonkadur.fate.v1.lang.type.Type;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class Access extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:access");
+      aliases.add("list:at_index");
+      aliases.add("list:atindex");
+      aliases.add("list:atIndex");
+      aliases.add("set:access");
+      aliases.add("set:at_index");
+      aliases.add("set:atindex");
+      aliases.add("set:atIndex");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation index;
+      Computation parent;
+      Type current_type;
+
+      if (call_parameters.size() != 2)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      index = call_parameters.get(0);
+      parent = call_parameters.get(1);
+
+      index.expect_non_string();
+      parent.expect_non_string();
+
+      current_type = parent.get_type();
+
+      while (current_type.can_be_used_as(PointerType.ARCHETYPE))
+      {
+         parent =
+            AtReference.build
+            (
+               origin,
+               "at",
+               Collections.singletonList(parent)
+            );
+
+         current_type = parent.get_type();
+      }
+
+      if (!index.get_type().can_be_used_as(Type.INT))
+      {
+         ErrorManager.handle
+         (
+            new InvalidTypeException
+            (
+               index.get_origin(),
+               current_type,
+               Collections.singleton(Type.INT),
+               index.toString()
+            )
+         );
+      }
+
+      if (alias.startsWith("set:"))
+      {
+         RecurrentChecks.assert_is_a_set(parent);
+      }
+      else
+      {
+         RecurrentChecks.assert_is_a_list(parent);
+      }
+
+      return new Access(origin, parent, current_type, index);
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Computation parent;
+   protected final Computation index;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected Access
+   (
+      final Origin origin,
+      final Computation parent,
+      final Type type,
+      final Computation index
+   )
+   {
+      super(origin, type);
+
+      this.parent = parent;
+      this.index = index;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+
+   /**** Accessors ************************************************************/
+   public Computation get_index ()
+   {
+      return index;
+   }
+
+   public Computation get_parent ()
+   {
+      return parent;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(Access (");
+      sb.append(type.get_name());
+      sb.append(") ");
+      sb.append(parent.toString());
+      sb.append(".");
+      sb.append(index.toString());
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/AddElementAtComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/AddElementAtComputation.java
new file mode 100644
index 0000000..aa50009
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/AddElementAtComputation.java
@@ -0,0 +1,149 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.Type;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class AddElementAtComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:add_element_at");
+      aliases.add("list:addelementat");
+      aliases.add("list:addElementAt");
+      aliases.add("list:add_at");
+      aliases.add("list:addat");
+      aliases.add("list:addAt");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String _alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation index;
+      final Computation element;
+      final Computation collection;
+
+      if (call_parameters.size() != 3)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      index = call_parameters.get(0);
+      element = call_parameters.get(1);
+      collection = call_parameters.get(2);
+
+      index.expect_non_string();
+
+      RecurrentChecks.propagate_expected_types_and_assert_is_a_list_of
+      (
+         collection,
+         element
+      );
+
+      RecurrentChecks.assert_can_be_used_as(index, Type.INT);
+
+      return new AddElementAtComputation(origin, index, element, collection);
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Computation index;
+   protected final Computation element;
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected AddElementAtComputation
+   (
+      final Origin origin,
+      final Computation index,
+      final Computation element,
+      final Computation collection
+   )
+   {
+      super(origin, collection.get_type());
+
+      this.index = index;
+      this.collection = collection;
+      this.element = element;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   public Computation get_index ()
+   {
+      return index;
+   }
+
+   public Computation get_element ()
+   {
+      return element;
+   }
+
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(AddElementAt");
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("index:");
+      sb.append(System.lineSeparator());
+      sb.append(index.toString());
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("element:");
+      sb.append(System.lineSeparator());
+      sb.append(element.toString());
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("collection:");
+      sb.append(System.lineSeparator());
+      sb.append(collection.toString());
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/AddElementComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/AddElementComputation.java
new file mode 100644
index 0000000..ef52eb4
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/AddElementComputation.java
@@ -0,0 +1,141 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class AddElementComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:add");
+      aliases.add("list:add_element");
+      aliases.add("list:addelement");
+      aliases.add("list:addElement");
+      aliases.add("set:add");
+      aliases.add("set:add_element");
+      aliases.add("set:addelement");
+      aliases.add("set:addElement");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation element;
+      final Computation collection;
+
+      if (call_parameters.size() != 2)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      element = call_parameters.get(0);
+      collection = call_parameters.get(1);
+
+      if (alias.startsWith("set:"))
+      {
+         RecurrentChecks.propagate_expected_types_and_assert_is_a_set_of
+         (
+            collection,
+            element
+         );
+      }
+      else
+      {
+         RecurrentChecks.propagate_expected_types_and_assert_is_a_list_of
+         (
+            collection,
+            element
+         );
+      }
+
+      return new AddElementComputation(origin, element, collection);
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Computation element;
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected AddElementComputation
+   (
+      final Origin origin,
+      final Computation element,
+      final Computation collection
+   )
+   {
+      super(origin, collection.get_type());
+
+      this.collection = collection;
+      this.element = element;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+
+   /**** Accessors ************************************************************/
+
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   public Computation get_element ()
+   {
+      return element;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(AddElement");
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("element:");
+      sb.append(System.lineSeparator());
+      sb.append(element.toString());
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("collection:");
+      sb.append(System.lineSeparator());
+      sb.append(collection.toString());
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/AddElementsOfComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/AddElementsOfComputation.java
new file mode 100644
index 0000000..4458df5
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/AddElementsOfComputation.java
@@ -0,0 +1,185 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.CollectionType;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class AddElementsOfComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:add_all");
+      aliases.add("list:addall");
+      aliases.add("list:addAll");
+
+      aliases.add("list:add_all_of");
+      aliases.add("list:addallof");
+      aliases.add("list:addAllOf");
+
+      aliases.add("list:add_elements");
+      aliases.add("list:addelements");
+      aliases.add("list:addElements");
+
+      aliases.add("list:add_elements_of");
+      aliases.add("list:addelementsof");
+      aliases.add("list:addElementsOf");
+
+      aliases.add("list:add_all_elements");
+      aliases.add("list:addallelements");
+      aliases.add("list:addAllElements");
+
+      aliases.add("list:add_all_elements_of");
+      aliases.add("list:addallelementsof");
+      aliases.add("list:addAllElementsOf");
+
+      aliases.add("set:add_all");
+      aliases.add("set:addall");
+      aliases.add("set:addAll");
+
+      aliases.add("set:add_all_of");
+      aliases.add("set:addallof");
+      aliases.add("set:addAllOf");
+
+      aliases.add("set:add_elements");
+      aliases.add("set:addelements");
+      aliases.add("set:addElements");
+
+      aliases.add("set:add_elements_of");
+      aliases.add("set:addelementsof");
+      aliases.add("set:addElementsOf");
+
+      aliases.add("set:add_all_elements");
+      aliases.add("set:addallelements");
+      aliases.add("set:addAllElements");
+
+      aliases.add("set:add_all_elements_of");
+      aliases.add("set:addallelementsof");
+      aliases.add("set:addAllElementsOf");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation other_collection;
+      final Computation collection;
+
+      if (call_parameters.size() != 2)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      other_collection = call_parameters.get(0);
+      collection = call_parameters.get(1);
+
+      other_collection.expect_non_string();
+      collection.expect_non_string();
+
+      if (alias.startsWith("set:"))
+      {
+         RecurrentChecks.assert_is_a_set(collection);
+      }
+      else
+      {
+         RecurrentChecks.assert_is_a_list(collection);
+      }
+
+      RecurrentChecks.assert_is_a_collection(other_collection);
+      RecurrentChecks.assert_can_be_used_as
+      (
+         other_collection.get_origin(),
+         ((CollectionType) other_collection.get_type()).get_content_type(),
+         ((CollectionType) collection.get_type()).get_content_type()
+      );
+
+      return new AddElementsOfComputation(origin, other_collection, collection);
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Computation other_collection;
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected AddElementsOfComputation
+   (
+      final Origin origin,
+      final Computation other_collection,
+      final Computation collection
+   )
+   {
+      super(origin, collection.get_type());
+
+      this.collection = collection;
+      this.other_collection = other_collection;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+
+   public Computation get_source_collection ()
+   {
+      return other_collection;
+   }
+
+   public Computation get_target_collection ()
+   {
+      return collection;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(AddElementsOf");
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("other_collection:");
+      sb.append(System.lineSeparator());
+      sb.append(other_collection.toString());
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("collection:");
+      sb.append(System.lineSeparator());
+      sb.append(collection.toString());
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/CarCdr.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/CarCdr.java
new file mode 100644
index 0000000..aae1102
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/CarCdr.java
@@ -0,0 +1,150 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+
+import tonkadur.error.ErrorManager;
+
+import tonkadur.fate.v1.error.InvalidTypeException;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+
+import tonkadur.fate.v1.lang.type.ConsType;
+import tonkadur.fate.v1.lang.type.Type;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class CarCdr extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("car");
+      aliases.add("cdr");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation parent;
+      final boolean is_car;
+      Type current_type;
+
+      if (call_parameters.size() != 1)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      parent = call_parameters.get(0);
+
+      parent.expect_non_string();
+
+      is_car = alias.equals("car");
+
+      current_type = parent.get_type();
+
+      if (!(current_type instanceof ConsType))
+      {
+         ErrorManager.handle
+         (
+            new InvalidTypeException
+            (
+               origin,
+               current_type,
+               Collections.singletonList(ConsType.ARCHETYPE)
+            )
+         );
+
+         current_type = Type.ANY;
+      }
+      else if (is_car)
+      {
+         current_type = ((ConsType) current_type).get_car_type();
+      }
+      else
+      {
+         current_type = ((ConsType) current_type).get_cdr_type();
+      }
+
+      return new CarCdr(origin, parent, is_car, current_type);
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Computation parent;
+   protected final boolean is_car;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected CarCdr
+   (
+      final Origin origin,
+      final Computation parent,
+      final boolean is_car,
+      final Type type
+   )
+   {
+      super(origin, type);
+
+      this.parent = parent;
+      this.is_car = is_car;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_parent ()
+   {
+      return parent;
+   }
+
+   public boolean is_car ()
+   {
+      return is_car;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      if (is_car)
+      {
+         sb.append("(car (");
+      }
+      else
+      {
+         sb.append("(cdr (");
+      }
+
+      sb.append(type.get_name());
+      sb.append(") ");
+      sb.append(parent);
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/ConsComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/ConsComputation.java
new file mode 100644
index 0000000..09488d4
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/ConsComputation.java
@@ -0,0 +1,112 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+
+import tonkadur.fate.v1.lang.type.ConsType;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class ConsComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("cons");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation car;
+      final Computation cdr;
+
+      if (call_parameters.size() != 2)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      car = call_parameters.get(0);
+      cdr = call_parameters.get(1);
+
+      car.expect_non_string();
+      cdr.expect_non_string();
+
+      return new ConsComputation(origin, car, cdr);
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Computation car;
+   protected final Computation cdr;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected ConsComputation
+   (
+      final Origin origin,
+      final Computation car,
+      final Computation cdr
+   )
+   {
+      super
+      (
+         origin,
+         new ConsType(origin, car.get_type(), cdr.get_type(), "auto generated")
+      );
+
+      this.car = car;
+      this.cdr = cdr;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_car ()
+   {
+      return car;
+   }
+
+   public Computation get_cdr ()
+   {
+      return cdr;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(Cons ");
+      sb.append(car.toString());
+      sb.append(" ");
+      sb.append(car.toString());
+      sb.append(") ");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/CountOperator.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/CountOperator.java
new file mode 100644
index 0000000..da473d3
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/CountOperator.java
@@ -0,0 +1,143 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import tonkadur.error.ErrorManager;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.Type;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class CountOperator extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:count");
+      aliases.add("list:number_of");
+      aliases.add("list:numberof");
+      aliases.add("list:numberOf");
+      aliases.add("set:count");
+      aliases.add("set:number_of");
+      aliases.add("set:numberof");
+      aliases.add("set:numberOf");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation element;
+      final Computation collection;
+
+      if (call_parameters.size() != 2)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      element = call_parameters.get(0);
+      collection = call_parameters.get(1);
+
+      if (alias.startsWith("set:"))
+      {
+         RecurrentChecks.propagate_expected_types_and_assert_is_a_set_of
+         (
+            collection,
+            element
+         );
+      }
+      else
+      {
+         RecurrentChecks.propagate_expected_types_and_assert_is_a_list_of
+         (
+            collection,
+            element
+         );
+      }
+
+      return new CountOperator(origin, element, collection);
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Computation element;
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected CountOperator
+   (
+      final Origin origin,
+      final Computation element,
+      final Computation collection
+   )
+   {
+      super(origin, Type.INT);
+
+      this.collection = collection;
+      this.element = element;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   public Computation get_element ()
+   {
+      return element;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(CountOperator");
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("element:");
+      sb.append(System.lineSeparator());
+      sb.append(element.toString());
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("collection:");
+      sb.append(System.lineSeparator());
+      sb.append(collection.toString());
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/FilterComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/FilterComputation.java
new file mode 100644
index 0000000..ec84cd0
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/FilterComputation.java
@@ -0,0 +1,190 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.ArrayList;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.Type;
+import tonkadur.fate.v1.lang.type.LambdaType;
+import tonkadur.fate.v1.lang.type.CollectionType;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class FilterComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:filter");
+      aliases.add("set:filter");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation lambda_function;
+      final Computation collection;
+      final List<Computation> extra_params;
+      final List<Type> signature;
+
+      if (call_parameters.size() < 2)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      lambda_function = call_parameters.get(0);
+      collection = call_parameters.get(1);
+
+      if (call_parameters.size() == 2)
+      {
+         extra_params = new ArrayList<Computation>();
+      }
+      else
+      {
+         extra_params = call_parameters.subList(2, call_parameters.size());
+      }
+
+      lambda_function.expect_non_string();
+      collection.expect_non_string();
+
+      RecurrentChecks.assert_is_a_lambda_function(lambda_function);
+
+      signature = ((LambdaType) lambda_function.get_type()).get_signature();
+
+      if (signature.size() < 1)
+      {
+         // TODO: Error.
+         System.err.println
+         (
+            "Lambda signature too small at "
+            + lambda_function.get_origin().toString()
+         );
+
+         return null;
+      }
+
+      if (signature.size() > 2)
+      {
+         RecurrentChecks.propagate_expected_types_and_assert_computations_matches_signature
+         (
+            origin,
+            extra_params,
+            signature.subList(1, signature.size())
+         );
+      }
+
+      if (alias.startsWith("set:"))
+      {
+         RecurrentChecks.assert_is_a_set_of(collection, signature.get(0));
+      }
+      else
+      {
+         RecurrentChecks.assert_is_a_list_of(collection, signature.get(0));
+      }
+
+      RecurrentChecks.assert_can_be_used_as
+      (
+         lambda_function.get_origin(),
+         ((LambdaType) lambda_function.get_type()).get_return_type(),
+         Type.BOOL
+      );
+
+      return
+         new FilterComputation
+         (
+            origin,
+            lambda_function,
+            collection,
+            extra_params
+         );
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final List<Computation> extra_params;
+   protected final Computation lambda_function;
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected FilterComputation
+   (
+      final Origin origin,
+      final Computation lambda_function,
+      final Computation collection,
+      final List<Computation> extra_params
+   )
+   {
+      super(origin, collection.get_type());
+
+      this.lambda_function = lambda_function;
+      this.collection = collection;
+      this.extra_params = extra_params;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_lambda_function ()
+   {
+      return lambda_function;
+   }
+
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(Filter ");
+      sb.append(lambda_function.toString());
+      sb.append(" ");
+      sb.append(collection.toString());
+
+      for (final Computation c: extra_params)
+      {
+         sb.append(" ");
+         sb.append(c.toString());
+      }
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/Fold.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/Fold.java
new file mode 100644
index 0000000..cb0f317
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/Fold.java
@@ -0,0 +1,251 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.Collection;
+import java.util.ArrayList;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.Type;
+import tonkadur.fate.v1.lang.type.LambdaType;
+import tonkadur.fate.v1.lang.type.CollectionType;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class Fold extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:foldl");
+      aliases.add("list:foldr");
+      aliases.add("list:fold_left");
+      aliases.add("list:foldleft");
+      aliases.add("list:foldLeft");
+      aliases.add("list:fold_right");
+      aliases.add("list:foldright");
+      aliases.add("list:foldRight");
+
+      aliases.add("set:foldl");
+      aliases.add("set:foldr");
+      aliases.add("set:fold_left");
+      aliases.add("set:foldleft");
+      aliases.add("set:foldLeft");
+      aliases.add("set:fold_right");
+      aliases.add("set:foldright");
+      aliases.add("set:foldRight");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation lambda_function;
+      final Computation initial_value;
+      final Computation collection;
+      final boolean is_foldl;
+      final List<Computation> extra_params;
+      final List<Type> signature;
+      final List<Type> expected_signature;
+
+      if (call_parameters.size() < 3)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      lambda_function = call_parameters.get(0);
+      initial_value = call_parameters.get(1);
+      collection = call_parameters.get(2);
+
+      lambda_function.expect_non_string();
+      collection.expect_non_string();
+
+      is_foldl = (alias.contains("foldl") || alias.contains("eft"));
+
+      if (call_parameters.size() == 3)
+      {
+         extra_params = new ArrayList<Computation>();
+      }
+      else
+      {
+         extra_params = call_parameters.subList(3, call_parameters.size());
+      }
+
+      signature = ((LambdaType) lambda_function.get_type()).get_signature();
+
+      if (signature.size() < 2)
+      {
+         // TODO: Error.
+         System.err.println
+         (
+            "Lambda signature too small at "
+            + lambda_function.get_origin().toString()
+         );
+
+         return null;
+      }
+
+      if (signature.size() > 2)
+      {
+         RecurrentChecks.propagate_expected_types_and_assert_computations_matches_signature
+         (
+            origin,
+            extra_params,
+            signature.subList(2, signature.size())
+         );
+      }
+
+      if (alias.startsWith("set:"))
+      {
+         RecurrentChecks.assert_is_a_set_of(collection, signature.get(0));
+      }
+      else
+      {
+         RecurrentChecks.assert_is_a_list_of(collection, signature.get(0));
+      }
+
+      RecurrentChecks.handle_expected_type_propagation
+      (
+         initial_value,
+         signature.get(1)
+      );
+
+      RecurrentChecks.assert_can_be_used_as
+      (
+         initial_value,
+         signature.get(1)
+      );
+
+      RecurrentChecks.assert_can_be_used_as
+      (
+         lambda_function.get_origin(),
+         ((LambdaType) lambda_function.get_type()).get_return_type(),
+         initial_value.get_type()
+      );
+
+      return
+         new Fold
+         (
+            origin,
+            lambda_function,
+            initial_value,
+            collection,
+            is_foldl,
+            extra_params,
+            initial_value.get_type()
+         );
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final List<Computation> extra_params;
+   protected final Computation lambda_function;
+   protected final Computation initial_value;
+   protected final Computation collection;
+   protected final boolean is_foldl;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected Fold
+   (
+      final Origin origin,
+      final Computation lambda_function,
+      final Computation initial_value,
+      final Computation collection,
+      final boolean is_foldl,
+      final List<Computation> extra_params,
+      final Type act_as
+   )
+   {
+      super(origin, act_as);
+
+      this.lambda_function = lambda_function;
+      this.initial_value = initial_value;
+      this.collection = collection;
+      this.is_foldl = is_foldl;
+      this.extra_params = extra_params;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_lambda_function ()
+   {
+      return lambda_function;
+   }
+
+   public Computation get_initial_value ()
+   {
+      return initial_value;
+   }
+
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   public boolean is_foldl ()
+   {
+      return is_foldl;
+   }
+
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      if (is_foldl)
+      {
+         sb.append("(Foldl ");
+      }
+      else
+      {
+         sb.append("(Foldr ");
+      }
+
+      sb.append(lambda_function.toString());
+
+      sb.append(" ");
+      sb.append(initial_value.toString());
+      sb.append(" ");
+      sb.append(collection.toString());
+
+      for (final Computation c: extra_params)
+      {
+         sb.append(" ");
+         sb.append(c.toString());
+      }
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/IndexOfOperator.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/IndexOfOperator.java
new file mode 100644
index 0000000..c042e18
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/IndexOfOperator.java
@@ -0,0 +1,138 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.Type;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class IndexOfOperator extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:index_of");
+      aliases.add("list:indexof");
+      aliases.add("list:indexOf");
+      aliases.add("set:index_of");
+      aliases.add("set:indexof");
+      aliases.add("set:indexOf");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation element;
+      final Computation collection;
+
+      if (call_parameters.size() != 2)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      element = call_parameters.get(0);
+      collection = call_parameters.get(1);
+
+      if (alias.startsWith("set:"))
+      {
+         RecurrentChecks.propagate_expected_types_and_assert_is_a_set_of
+         (
+            collection,
+            element
+         );
+      }
+      else
+      {
+         RecurrentChecks.propagate_expected_types_and_assert_is_a_list_of
+         (
+            collection,
+            element
+         );
+      }
+
+      return new IndexOfOperator(origin, element, collection);
+   }
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Computation element;
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected IndexOfOperator
+   (
+      final Origin origin,
+      final Computation element,
+      final Computation collection
+   )
+   {
+      super(origin, Type.INT);
+
+      this.collection = collection;
+      this.element = element;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   public Computation get_element ()
+   {
+      return element;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(IndexOfOperator");
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("element:");
+      sb.append(System.lineSeparator());
+      sb.append(element.toString());
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("collection:");
+      sb.append(System.lineSeparator());
+      sb.append(collection.toString());
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/IndexedFilterComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/IndexedFilterComputation.java
new file mode 100644
index 0000000..1d17a99
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/IndexedFilterComputation.java
@@ -0,0 +1,153 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.ArrayList;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.Type;
+import tonkadur.fate.v1.lang.type.CollectionType;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class IndexedFilterComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:indexed_filter");
+      aliases.add("list:indexedfilter");
+      aliases.add("list:indexedFilter");
+      aliases.add("list:ifilter");
+      aliases.add("set:indexed_filter");
+      aliases.add("set:indexedfilter");
+      aliases.add("set:indexedFilter");
+      aliases.add("set:ifilter");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      // TODO: implement
+      final Computation lambda_function = null;
+      final Computation collection = null;
+      final List<Computation> extra_params = null;
+      final List<Type> target_signature;
+
+      target_signature = new ArrayList<Type>();
+
+      RecurrentChecks.assert_is_a_collection(collection);
+
+      target_signature.add(Type.INT);
+      target_signature.add
+      (
+         ((CollectionType) collection.get_type()).get_content_type()
+      );
+
+      for (final Computation c: extra_params)
+      {
+         target_signature.add(c.get_type());
+      }
+
+      RecurrentChecks.assert_lambda_matches_types
+      (
+         lambda_function,
+         Type.BOOL,
+         target_signature
+      );
+
+      return
+         new IndexedFilterComputation
+         (
+            origin,
+            lambda_function,
+            collection,
+            extra_params
+         );
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final List<Computation> extra_params;
+   protected final Computation lambda_function;
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected IndexedFilterComputation
+   (
+      final Origin origin,
+      final Computation lambda_function,
+      final Computation collection,
+      final List<Computation> extra_params
+   )
+   {
+      super(origin, collection.get_type());
+
+      this.lambda_function = lambda_function;
+      this.collection = collection;
+      this.extra_params = extra_params;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_lambda_function ()
+   {
+      return lambda_function;
+   }
+
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(IndexedFilter ");
+      sb.append(lambda_function.toString());
+      sb.append(" ");
+      sb.append(collection.toString());
+
+      for (final Computation c: extra_params)
+      {
+         sb.append(" ");
+         sb.append(c.toString());
+      }
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/IndexedMapComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/IndexedMapComputation.java
new file mode 100644
index 0000000..717dc53
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/IndexedMapComputation.java
@@ -0,0 +1,156 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.ArrayList;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.Type;
+import tonkadur.fate.v1.lang.type.LambdaType;
+import tonkadur.fate.v1.lang.type.CollectionType;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class IndexedMapComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:indexed_map");
+      aliases.add("list:indexedmap");
+      aliases.add("list:indexedMap");
+      aliases.add("list:imap");
+      aliases.add("set:indexed_map");
+      aliases.add("set:indexedmap");
+      aliases.add("set:indexedMap");
+      aliases.add("set:imap");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      // TODO: implement
+      final Computation lambda_function = null;
+      final Computation collection = null;
+      final List<Computation> extra_params = null;
+      final List<Type> in_types;
+
+      in_types = new ArrayList<Type>();
+
+      RecurrentChecks.assert_is_a_collection(collection);
+
+      in_types.add(Type.INT);
+      in_types.add
+      (
+         ((CollectionType) collection.get_type()).get_content_type()
+      );
+
+      for (final Computation c: extra_params)
+      {
+         in_types.add(c.get_type());
+      }
+
+      RecurrentChecks.assert_lambda_matches_types(lambda_function, in_types);
+
+      return
+         new IndexedMapComputation
+         (
+            origin,
+            lambda_function,
+            collection,
+            extra_params,
+            CollectionType.build
+            (
+               origin,
+               ((LambdaType) lambda_function.get_type()).get_return_type(),
+               ((CollectionType) collection.get_type()).is_set(),
+               "auto generated"
+            )
+         );
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final List<Computation> extra_params;
+   protected final Computation lambda_function;
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected IndexedMapComputation
+   (
+      final Origin origin,
+      final Computation lambda_function,
+      final Computation collection,
+      final List<Computation> extra_params,
+      final Type output_type
+   )
+   {
+      super(origin, output_type);
+
+      this.lambda_function = lambda_function;
+      this.collection = collection;
+      this.extra_params = extra_params;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_lambda_function ()
+   {
+      return lambda_function;
+   }
+
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(IndexedMap ");
+      sb.append(lambda_function.toString());
+      sb.append(" ");
+      sb.append(collection.toString());
+
+      for (final Computation c: extra_params)
+      {
+         sb.append(" ");
+         sb.append(c.toString());
+      }
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/IndexedMergeComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/IndexedMergeComputation.java
new file mode 100644
index 0000000..021c4ce
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/IndexedMergeComputation.java
@@ -0,0 +1,266 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.Collection;
+import java.util.ArrayList;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.Type;
+import tonkadur.fate.v1.lang.type.LambdaType;
+import tonkadur.fate.v1.lang.type.CollectionType;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class IndexedMergeComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:indexed_merge");
+      aliases.add("list:indexedmerge");
+      aliases.add("list:indexedMerge");
+      aliases.add("list:imerge");
+      aliases.add("set:indexed_merge");
+      aliases.add("set:indexedmerge");
+      aliases.add("set:indexedMerge");
+      aliases.add("set:imerge");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      // TODO: implement
+      final Computation lambda_function = null;
+      final Computation collection_in_a = null;
+      final Computation default_a = null;
+      final Computation collection_in_b = null;
+      final Computation default_b = null;
+      final boolean to_set = false;
+      final List<Computation> extra_params = null;
+      final List<Type> types_in;
+
+      types_in = new ArrayList<Type>();
+
+      if (default_a == null)
+      {
+         RecurrentChecks.assert_is_a_collection(collection_in_a);
+      }
+      else
+      {
+         RecurrentChecks.propagate_expected_types_and_assert_is_a_collection_of
+         (
+            collection_in_a,
+            default_a
+         );
+      }
+
+      if (default_b == null)
+      {
+         RecurrentChecks.assert_is_a_collection(collection_in_b);
+      }
+      else
+      {
+         RecurrentChecks.propagate_expected_types_and_assert_is_a_collection_of
+         (
+            collection_in_b,
+            default_b
+         );
+      }
+
+      types_in.add(Type.INT);
+
+      types_in.add
+      (
+         ((CollectionType) collection_in_a.get_type()).get_content_type()
+      );
+
+      if (default_b != null)
+      {
+         /*
+          * Safe-Mode: two indices.
+          * Unsafe-Mode: only one index, since out-of-bound means stopping.
+          */
+         types_in.add(Type.INT);
+      }
+
+      types_in.add
+      (
+         ((CollectionType) collection_in_b.get_type()).get_content_type()
+      );
+
+      for (final Computation c: extra_params)
+      {
+         types_in.add(c.get_type());
+      }
+
+      RecurrentChecks.assert_lambda_matches_types(lambda_function, types_in);
+
+      return
+         new IndexedMergeComputation
+         (
+            origin,
+            lambda_function,
+            collection_in_a,
+            default_a,
+            collection_in_b,
+            default_b,
+            to_set,
+            extra_params,
+            CollectionType.build
+            (
+               origin,
+               ((LambdaType) lambda_function.get_type()).get_return_type(),
+               to_set,
+               "auto generated"
+            )
+         );
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final List<Computation> extra_params;
+   protected final Computation lambda_function;
+   protected final Computation collection_in_a;
+   protected final Computation default_a;
+   protected final Computation collection_in_b;
+   protected final Computation default_b;
+   protected final boolean to_set;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected IndexedMergeComputation
+   (
+      final Origin origin,
+      final Computation lambda_function,
+      final Computation collection_in_a,
+      final Computation default_a,
+      final Computation collection_in_b,
+      final Computation default_b,
+      final boolean to_set,
+      final List<Computation> extra_params,
+      final Type output_type
+   )
+   {
+      super(origin, output_type);
+
+      this.lambda_function = lambda_function;
+      this.collection_in_a = collection_in_a;
+      this.default_a = default_a;
+      this.collection_in_b = collection_in_b;
+      this.default_b = default_b;
+      this.to_set = to_set;
+      this.extra_params = extra_params;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_lambda_function ()
+   {
+      return lambda_function;
+   }
+
+   public Computation get_collection_in_a ()
+   {
+      return collection_in_a;
+   }
+
+   public Computation get_default_a ()
+   {
+      return default_a;
+   }
+
+   public Computation get_collection_in_b ()
+   {
+      return collection_in_b;
+   }
+
+   public Computation get_default_b ()
+   {
+      return default_b;
+   }
+
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
+   public boolean to_set ()
+   {
+      return to_set;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      if (to_set)
+      {
+         sb.append("(IndexedMergeToSet ");
+      }
+      else
+      {
+         sb.append("(IndexedMergeToList ");
+      }
+
+      sb.append(lambda_function.toString());
+      sb.append(" ");
+      sb.append(collection_in_a.toString());
+      sb.append(" ");
+
+      if (default_a == null)
+      {
+         sb.append("null");
+      }
+      else
+      {
+         sb.append(default_a.toString());
+      }
+
+      sb.append(" ");
+      sb.append(collection_in_b.toString());
+      sb.append(" ");
+
+      if (default_b == null)
+      {
+         sb.append("null");
+      }
+      else
+      {
+         sb.append(default_b.toString());
+      }
+
+      for (final Computation c: extra_params)
+      {
+         sb.append(" ");
+         sb.append(c.toString());
+      }
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/IndexedPartitionComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/IndexedPartitionComputation.java
new file mode 100644
index 0000000..46df979
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/IndexedPartitionComputation.java
@@ -0,0 +1,167 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.ArrayList;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.CollectionType;
+import tonkadur.fate.v1.lang.type.ConsType;
+import tonkadur.fate.v1.lang.type.Type;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class IndexedPartitionComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:indexed_partition");
+      aliases.add("list:indexedpartition");
+      aliases.add("list:indexedPartition");
+      aliases.add("list:ipartition");
+      aliases.add("set:indexed_partition");
+      aliases.add("set:indexedpartition");
+      aliases.add("set:indexedPartition");
+      aliases.add("set:ipartition");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      // TODO: implement
+      final Computation lambda_function = null;
+      final Computation collection = null;
+      final List<Computation> extra_params = null;
+      final Type type;
+      final List<Type> target_signature;
+
+      target_signature = new ArrayList<Type>();
+
+      RecurrentChecks.assert_is_a_collection(collection);
+
+      target_signature.add(Type.INT);
+
+      target_signature.add
+      (
+         ((CollectionType) collection.get_type()).get_content_type()
+      );
+
+      for (final Computation c: extra_params)
+      {
+         target_signature.add(c.get_type());
+      }
+
+      RecurrentChecks.assert_lambda_matches_types
+      (
+         lambda_function,
+         Type.BOOL,
+         target_signature
+      );
+
+      type =
+         new ConsType
+         (
+            origin,
+            collection.get_type(),
+            collection.get_type(),
+            "auto generated"
+         );
+
+      return
+         new IndexedPartitionComputation
+         (
+            origin,
+            lambda_function,
+            collection,
+            extra_params,
+            type
+         );
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final List<Computation> extra_params;
+   protected final Computation lambda_function;
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected IndexedPartitionComputation
+   (
+      final Origin origin,
+      final Computation lambda_function,
+      final Computation collection,
+      final List<Computation> extra_params,
+      final Type output_type
+   )
+   {
+      super(origin, output_type);
+
+      this.lambda_function = lambda_function;
+      this.collection = collection;
+      this.extra_params = extra_params;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_lambda_function ()
+   {
+      return lambda_function;
+   }
+
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(IndexedPartition ");
+      sb.append(lambda_function.toString());
+      sb.append(" ");
+      sb.append(collection.toString());
+
+      for (final Computation c: extra_params)
+      {
+         sb.append(" ");
+         sb.append(c.toString());
+      }
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/IsEmpty.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/IsEmpty.java
new file mode 100644
index 0000000..6b2d177
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/IsEmpty.java
@@ -0,0 +1,125 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.Type;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class IsEmpty extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:empty?");
+      aliases.add("list:empty");
+      aliases.add("list:is_empty?");
+      aliases.add("list:isempty?");
+      aliases.add("list:isEmpty?");
+      aliases.add("list:is_empty");
+      aliases.add("list:isempty");
+      aliases.add("list:isEmpty");
+
+      aliases.add("set:empty?");
+      aliases.add("set:empty");
+      aliases.add("set:is_empty?");
+      aliases.add("set:isempty?");
+      aliases.add("set:isEmpty?");
+      aliases.add("set:is_empty");
+      aliases.add("set:isempty");
+      aliases.add("set:isEmpty");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation collection;
+
+      if (call_parameters.size() != 1)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      collection = call_parameters.get(0);
+
+      if (alias.startsWith("set:"))
+      {
+         RecurrentChecks.assert_is_a_set(collection);
+      }
+      else
+      {
+         RecurrentChecks.assert_is_a_list(collection);
+      }
+
+      return new IsEmpty(origin, collection);
+   }
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected IsEmpty
+   (
+      final Origin origin,
+      final Computation collection
+   )
+   {
+      super(origin, Type.BOOL);
+
+      this.collection = collection;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(IsEmpty");
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("collection:");
+      sb.append(System.lineSeparator());
+      sb.append(collection.toString());
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/IsMemberOperator.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/IsMemberOperator.java
new file mode 100644
index 0000000..0670d63
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/IsMemberOperator.java
@@ -0,0 +1,148 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.Type;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class IsMemberOperator extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:is_member?");
+      aliases.add("list:ismember?");
+      aliases.add("list:isMember?");
+      aliases.add("list:member?");
+      aliases.add("list:member");
+      aliases.add("list:is_member");
+      aliases.add("list:ismember");
+      aliases.add("list:isMember");
+      aliases.add("set:is_member?");
+      aliases.add("set:ismember?");
+      aliases.add("set:isMember?");
+      aliases.add("set:member?");
+      aliases.add("set:member");
+      aliases.add("set:is_member");
+      aliases.add("set:ismember");
+      aliases.add("set:isMember");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation element;
+      final Computation collection;
+
+      if (call_parameters.size() != 2)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      element = call_parameters.get(0);
+      collection = call_parameters.get(1);
+
+      if (alias.startsWith("set:"))
+      {
+         RecurrentChecks.propagate_expected_types_and_assert_is_a_set_of
+         (
+            collection,
+            element
+         );
+      }
+      else
+      {
+         RecurrentChecks.propagate_expected_types_and_assert_is_a_list_of
+         (
+            collection,
+            element
+         );
+      }
+
+      return new IsMemberOperator(origin, element, collection);
+   }
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Computation element;
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected IsMemberOperator
+   (
+      final Origin origin,
+      final Computation element,
+      final Computation collection
+   )
+   {
+      super(origin, Type.BOOL);
+
+      this.collection = collection;
+      this.element = element;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   public Computation get_element ()
+   {
+      return element;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(IsMemberOperator");
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("element:");
+      sb.append(System.lineSeparator());
+      sb.append(element.toString());
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("collection:");
+      sb.append(System.lineSeparator());
+      sb.append(collection.toString());
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/MapComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/MapComputation.java
new file mode 100644
index 0000000..e271285
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/MapComputation.java
@@ -0,0 +1,153 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.ArrayList;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.Type;
+import tonkadur.fate.v1.lang.type.LambdaType;
+import tonkadur.fate.v1.lang.type.CollectionType;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class MapComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:map");
+      aliases.add("set:map");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      // TODO: implement
+      final Computation lambda_function = null;
+      final Computation collection = null;
+      final List<Computation> extra_params = null;
+      final List<Type> target_signature;
+
+      target_signature = new ArrayList<Type>();
+
+      RecurrentChecks.assert_is_a_collection(collection);
+
+      target_signature.add
+      (
+         ((CollectionType) collection.get_type()).get_content_type()
+      );
+
+      for (final Computation c: extra_params)
+      {
+         target_signature.add(c.get_type());
+      }
+
+      RecurrentChecks.assert_lambda_matches_types
+      (
+         lambda_function,
+         target_signature
+      );
+
+      return
+         new MapComputation
+         (
+            origin,
+            lambda_function,
+            collection,
+            extra_params,
+            CollectionType.build
+            (
+               origin,
+               ((LambdaType) lambda_function.get_type()).get_return_type(),
+               ((CollectionType) collection.get_type()).is_set(),
+               "auto generated"
+            )
+         );
+   }
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final List<Computation> extra_params;
+   protected final Computation lambda_function;
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected MapComputation
+   (
+      final Origin origin,
+      final Computation lambda_function,
+      final Computation collection,
+      final List<Computation> extra_params,
+      final Type output_type
+   )
+   {
+      super(origin, output_type);
+
+      this.lambda_function = lambda_function;
+      this.collection = collection;
+      this.extra_params = extra_params;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_lambda_function ()
+   {
+      return lambda_function;
+   }
+
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(Map ");
+      sb.append(lambda_function.toString());
+      sb.append(" ");
+      sb.append(collection.toString());
+
+      for (final Computation c: extra_params)
+      {
+         sb.append(" ");
+         sb.append(c.toString());
+      }
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/MergeComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/MergeComputation.java
new file mode 100644
index 0000000..2354ba3
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/MergeComputation.java
@@ -0,0 +1,248 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.Type;
+import tonkadur.fate.v1.lang.type.LambdaType;
+import tonkadur.fate.v1.lang.type.CollectionType;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class MergeComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:merge");
+      aliases.add("set:merge");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      // TODO: implement
+      final Computation lambda_function = null;
+      final Computation collection_in_a = null;
+      final Computation default_a = null;
+      final Computation collection_in_b = null;
+      final Computation default_b = null;
+      final boolean to_set = false;
+      final List<Computation> extra_params = null;
+      final List<Type> types_in;
+
+      types_in = new ArrayList<Type>();
+
+      if (default_a == null)
+      {
+         RecurrentChecks.assert_is_a_collection(collection_in_a);
+      }
+      else
+      {
+         RecurrentChecks.propagate_expected_types_and_assert_is_a_collection_of
+         (
+            collection_in_a,
+            default_a
+         );
+      }
+
+      if (default_b == null)
+      {
+         RecurrentChecks.assert_is_a_collection(collection_in_b);
+      }
+      else
+      {
+         RecurrentChecks.propagate_expected_types_and_assert_is_a_collection_of
+         (
+            collection_in_b,
+            default_b
+         );
+      }
+
+      types_in.add
+      (
+         ((CollectionType) collection_in_a.get_type()).get_content_type()
+      );
+
+      types_in.add
+      (
+         ((CollectionType) collection_in_b.get_type()).get_content_type()
+      );
+
+      for (final Computation c: extra_params)
+      {
+         types_in.add(c.get_type());
+      }
+
+      RecurrentChecks.assert_lambda_matches_types(lambda_function, types_in);
+
+      return
+         new MergeComputation
+         (
+            origin,
+            lambda_function,
+            collection_in_a,
+            default_a,
+            collection_in_b,
+            default_b,
+            to_set,
+            extra_params,
+            CollectionType.build
+            (
+               origin,
+               ((LambdaType) lambda_function.get_type()).get_return_type(),
+               to_set,
+               "auto generated"
+            )
+         );
+   }
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final List<Computation> extra_params;
+   protected final Computation lambda_function;
+   protected final Computation collection_in_a;
+   protected final Computation default_a;
+   protected final Computation collection_in_b;
+   protected final Computation default_b;
+   protected final boolean to_set;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected MergeComputation
+   (
+      final Origin origin,
+      final Computation lambda_function,
+      final Computation collection_in_a,
+      final Computation default_a,
+      final Computation collection_in_b,
+      final Computation default_b,
+      final boolean to_set,
+      final List<Computation> extra_params,
+      final Type output_type
+   )
+   {
+      super(origin, output_type);
+
+      this.lambda_function = lambda_function;
+      this.collection_in_a = collection_in_a;
+      this.default_a = default_a;
+      this.collection_in_b = collection_in_b;
+      this.default_b = default_b;
+      this.to_set = to_set;
+      this.extra_params = extra_params;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_lambda_function ()
+   {
+      return lambda_function;
+   }
+
+   public Computation get_collection_in_a ()
+   {
+      return collection_in_a;
+   }
+
+   public Computation get_default_a ()
+   {
+      return default_a;
+   }
+
+   public Computation get_collection_in_b ()
+   {
+      return collection_in_b;
+   }
+
+   public Computation get_default_b ()
+   {
+      return default_b;
+   }
+
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
+   public boolean to_set ()
+   {
+      return to_set;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      if (to_set)
+      {
+         sb.append("(MergeToSet ");
+      }
+      else
+      {
+         sb.append("(MergeToList ");
+      }
+
+      sb.append(lambda_function.toString());
+      sb.append(" ");
+      sb.append(collection_in_a.toString());
+      sb.append(" ");
+
+      if (default_a == null)
+      {
+         sb.append("null");
+      }
+      else
+      {
+         sb.append(default_a.toString());
+      }
+
+      sb.append(" ");
+      sb.append(collection_in_b.toString());
+      sb.append(" ");
+
+      if (default_b == null)
+      {
+         sb.append("null");
+      }
+      else
+      {
+         sb.append(default_b.toString());
+      }
+
+      for (final Computation c: extra_params)
+      {
+         sb.append(" ");
+         sb.append(c.toString());
+      }
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/PartitionComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/PartitionComputation.java
new file mode 100644
index 0000000..32e655d
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/PartitionComputation.java
@@ -0,0 +1,159 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.ArrayList;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.CollectionType;
+import tonkadur.fate.v1.lang.type.ConsType;
+import tonkadur.fate.v1.lang.type.Type;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class PartitionComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:partition");
+      aliases.add("set:partition");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      // TODO: implement
+      final Computation lambda_function = null;
+      final Computation collection = null;
+      final List<Computation> extra_params = null;
+      final Type type;
+      final List<Type> target_signature;
+
+      target_signature = new ArrayList<Type>();
+
+      RecurrentChecks.assert_is_a_collection(collection);
+
+      target_signature.add
+      (
+         ((CollectionType) collection.get_type()).get_content_type()
+      );
+
+      for (final Computation c: extra_params)
+      {
+         target_signature.add(c.get_type());
+      }
+
+      RecurrentChecks.assert_lambda_matches_types
+      (
+         lambda_function,
+         Type.BOOL,
+         target_signature
+      );
+
+      type =
+         new ConsType
+         (
+            origin,
+            collection.get_type(),
+            collection.get_type(),
+            "auto generated"
+         );
+
+      return
+         new PartitionComputation
+         (
+            origin,
+            lambda_function,
+            collection,
+            extra_params,
+            type
+         );
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final List<Computation> extra_params;
+   protected final Computation lambda_function;
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected PartitionComputation
+   (
+      final Origin origin,
+      final Computation lambda_function,
+      final Computation collection,
+      final List<Computation> extra_params,
+      final Type output_type
+   )
+   {
+      super(origin, output_type);
+
+      this.lambda_function = lambda_function;
+      this.collection = collection;
+      this.extra_params = extra_params;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_lambda_function ()
+   {
+      return lambda_function;
+   }
+
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(Partition ");
+      sb.append(lambda_function.toString());
+      sb.append(" ");
+      sb.append(collection.toString());
+
+      for (final Computation c: extra_params)
+      {
+         sb.append(" ");
+         sb.append(c.toString());
+      }
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/PopElementComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/PopElementComputation.java
new file mode 100644
index 0000000..667ad6b
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/PopElementComputation.java
@@ -0,0 +1,146 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class PopElementComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:popleft");
+      aliases.add("list:pop_left");
+      aliases.add("list:popLeft");
+      aliases.add("list:popleftelement");
+      aliases.add("list:pop_left_element");
+      aliases.add("list:popLeftElement");
+      aliases.add("list:popright");
+      aliases.add("list:pop_right");
+      aliases.add("list:popRight");
+      aliases.add("list:poprightelement");
+      aliases.add("list:pop_right_element");
+      aliases.add("list:popRightElement");
+      aliases.add("set:popleft");
+      aliases.add("set:pop_left");
+      aliases.add("set:popLeft");
+      aliases.add("set:popleftelement");
+      aliases.add("set:pop_left_element");
+      aliases.add("set:popLeftElement");
+      aliases.add("set:popright");
+      aliases.add("set:pop_right");
+      aliases.add("set:popRight");
+      aliases.add("set:poprightelement");
+      aliases.add("set:pop_right_element");
+      aliases.add("set:popRightElement");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation collection;
+      final boolean is_from_left;
+
+      if (call_parameters.size() != 1)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      collection = call_parameters.get(0);
+
+      collection.expect_non_string();
+
+      is_from_left = alias.contains("eft");
+
+      if (alias.startsWith("set:"))
+      {
+         RecurrentChecks.assert_is_a_set(collection);
+      }
+      else
+      {
+         RecurrentChecks.assert_is_a_list(collection);
+      }
+
+      return new PopElementComputation(origin, collection, is_from_left);
+   }
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Computation collection;
+   protected final boolean is_from_left;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected PopElementComputation
+   (
+      final Origin origin,
+      final Computation collection,
+      final boolean is_from_left
+   )
+   {
+      super(origin, collection.get_type());
+
+      this.collection = collection;
+      this.is_from_left = is_from_left;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   public boolean is_from_left ()
+   {
+      return is_from_left;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      if (is_from_left)
+      {
+         sb.append("(PopLeftElement ");
+      }
+      else
+      {
+         sb.append("(PopRightElement ");
+      }
+
+      sb.append(collection.toString());
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/PushElementComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/PushElementComputation.java
new file mode 100644
index 0000000..69c7e7f
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/PushElementComputation.java
@@ -0,0 +1,166 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class PushElementComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:push_left");
+      aliases.add("list:pushleft");
+      aliases.add("list:pushLeft");
+      aliases.add("list:push_right");
+      aliases.add("list:pushright");
+      aliases.add("list:pushRight");
+      aliases.add("set:push_left");
+      aliases.add("set:pushleft");
+      aliases.add("set:pushLeft");
+      aliases.add("set:push_right");
+      aliases.add("set:pushright");
+      aliases.add("set:pushRight");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation element;
+      final Computation collection;
+      final boolean is_from_left;
+
+      if (call_parameters.size() != 2)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      collection = call_parameters.get(0);
+      element = call_parameters.get(1);
+      is_from_left = alias.contains("eft");
+
+      if (alias.startsWith("set:"))
+      {
+         RecurrentChecks.propagate_expected_types_and_assert_is_a_set_of
+         (
+            collection,
+            element
+         );
+      }
+      else
+      {
+         RecurrentChecks.propagate_expected_types_and_assert_is_a_list_of
+         (
+            collection,
+            element
+         );
+      }
+      return
+         new PushElementComputation
+         (
+            origin,
+            element,
+            collection,
+            is_from_left
+         );
+   }
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Computation element;
+   protected final Computation collection;
+   protected final boolean is_from_left;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected PushElementComputation
+   (
+      final Origin origin,
+      final Computation element,
+      final Computation collection,
+      final boolean is_from_left
+   )
+   {
+      super(origin, collection.get_type());
+
+      this.collection = collection;
+      this.element = element;
+      this.is_from_left = is_from_left;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   public Computation get_element ()
+   {
+      return element;
+   }
+
+   public boolean  is_from_left ()
+   {
+      return is_from_left;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      if (is_from_left)
+      {
+         sb.append("(LeftPushElement");
+      }
+      else
+      {
+         sb.append("(RightPushElement");
+      }
+
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("element:");
+      sb.append(System.lineSeparator());
+      sb.append(element.toString());
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("collection:");
+      sb.append(System.lineSeparator());
+      sb.append(collection.toString());
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/Range.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/Range.java
new file mode 100644
index 0000000..f58cb1c
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/Range.java
@@ -0,0 +1,137 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.CollectionType;
+import tonkadur.fate.v1.lang.type.Type;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class Range extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:range");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation start;
+      final Computation end;
+      final Computation increment;
+
+      if (call_parameters.size() != 3)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      start = call_parameters.get(0);
+      end = call_parameters.get(1);
+      increment = call_parameters.get(2);
+
+      start.expect_non_string();
+      end.expect_non_string();
+      increment.expect_non_string();
+
+      RecurrentChecks.assert_can_be_used_as(start, Type.INT);
+      RecurrentChecks.assert_can_be_used_as(end, Type.INT);
+      RecurrentChecks.assert_can_be_used_as(increment, Type.INT);
+
+      return
+         new Range
+         (
+            origin,
+            start,
+            end,
+            increment,
+            CollectionType.build(origin, Type.INT, false, "auto generated")
+         );
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Computation start;
+   protected final Computation end;
+   protected final Computation increment;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected Range
+   (
+      final Origin origin,
+      final Computation start,
+      final Computation end,
+      final Computation increment,
+      final Type target_type
+   )
+   {
+      super(origin, target_type);
+
+      this.start = start;
+      this.end = end;
+      this.increment = increment;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_start ()
+   {
+      return start;
+   }
+
+   public Computation get_end ()
+   {
+      return end;
+   }
+
+   public Computation get_increment ()
+   {
+      return increment;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(Range ");
+      sb.append(start.toString());
+      sb.append(" ");
+      sb.append(end.toString());
+      sb.append(" ");
+      sb.append(increment.toString());
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/RemoveAllOfElementComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/RemoveAllOfElementComputation.java
new file mode 100644
index 0000000..858aeb5
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/RemoveAllOfElementComputation.java
@@ -0,0 +1,137 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Collection;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class RemoveAllOfElementComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:remove_each");
+      aliases.add("list:removeeach");
+      aliases.add("list:removeEach");
+      aliases.add("set:remove_each");
+      aliases.add("set:removeeach");
+      aliases.add("set:removeEach");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation element;
+      final Computation collection;
+
+      if (call_parameters.size() != 2)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      element = call_parameters.get(0);
+      collection = call_parameters.get(1);
+
+      if (alias.startsWith("set:"))
+      {
+         RecurrentChecks.propagate_expected_types_and_assert_is_a_set_of
+         (
+            collection,
+            element
+         );
+      }
+      else
+      {
+         RecurrentChecks.propagate_expected_types_and_assert_is_a_list_of
+         (
+            collection,
+            element
+         );
+      }
+
+      return new RemoveAllOfElementComputation(origin, element, collection);
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Computation element;
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected RemoveAllOfElementComputation
+   (
+      final Origin origin,
+      final Computation element,
+      final Computation collection
+   )
+   {
+      super(origin, collection.get_type());
+
+      this.collection = collection;
+      this.element = element;
+   }
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_element ()
+   {
+      return element;
+   }
+
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(RemoveAllOfElement");
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("element:");
+      sb.append(System.lineSeparator());
+      sb.append(element.toString());
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("collection:");
+      sb.append(System.lineSeparator());
+      sb.append(collection.toString());
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/RemoveElementAtComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/RemoveElementAtComputation.java
new file mode 100644
index 0000000..781f4e1
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/RemoveElementAtComputation.java
@@ -0,0 +1,137 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Collection;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.Type;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class RemoveElementAtComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:remove_at");
+      aliases.add("list:removeat");
+      aliases.add("list:removeAt");
+      aliases.add("set:remove_at");
+      aliases.add("set:removeat");
+      aliases.add("set:removeAt");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation index;
+      final Computation collection;
+
+      if (call_parameters.size() != 2)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      index = call_parameters.get(0);
+      collection = call_parameters.get(1);
+
+      index.expect_non_string();
+      collection.expect_non_string();
+
+      if (alias.startsWith("set:"))
+      {
+         RecurrentChecks.assert_is_a_set(collection);
+      }
+      else
+      {
+         RecurrentChecks.assert_is_a_list(collection);
+      }
+
+      RecurrentChecks.assert_can_be_used_as(index, Type.INT);
+
+      return new RemoveElementAtComputation(origin, index, collection);
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Computation index;
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected RemoveElementAtComputation
+   (
+      final Origin origin,
+      final Computation index,
+      final Computation collection
+   )
+   {
+      super(origin, collection.get_type());
+
+      this.collection = collection;
+      this.index = index;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_index ()
+   {
+      return index;
+   }
+
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(RemoveElementAt");
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("index:");
+      sb.append(System.lineSeparator());
+      sb.append(index.toString());
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("collection:");
+      sb.append(System.lineSeparator());
+      sb.append(collection.toString());
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/RemoveElementComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/RemoveElementComputation.java
new file mode 100644
index 0000000..a75f0cd
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/RemoveElementComputation.java
@@ -0,0 +1,145 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class RemoveElementComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:remove");
+      aliases.add("list:remove_one");
+      aliases.add("list:remove_once");
+      aliases.add("list:removeone");
+      aliases.add("list:removeonce");
+      aliases.add("list:removeOne");
+      aliases.add("list:removeOnce");
+      aliases.add("set:remove");
+      aliases.add("set:remove_one");
+      aliases.add("set:remove_once");
+      aliases.add("set:removeone");
+      aliases.add("set:removeonce");
+      aliases.add("set:removeOne");
+      aliases.add("set:removeOnce");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation element;
+      final Computation collection;
+
+      if (call_parameters.size() != 1)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      element = call_parameters.get(0);
+      collection = call_parameters.get(1);
+
+      if (alias.startsWith("set:"))
+      {
+         RecurrentChecks.propagate_expected_types_and_assert_is_a_set_of
+         (
+            collection,
+            element
+         );
+      }
+      else
+      {
+         RecurrentChecks.propagate_expected_types_and_assert_is_a_list_of
+         (
+            collection,
+            element
+         );
+      }
+
+      return new RemoveElementComputation(origin, element, collection);
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Computation element;
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected RemoveElementComputation
+   (
+      final Origin origin,
+      final Computation element,
+      final Computation collection
+   )
+   {
+      super(origin, collection.get_type());
+
+      this.collection = collection;
+      this.element = element;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_element ()
+   {
+      return element;
+   }
+
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(RemoveElement");
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("element:");
+      sb.append(System.lineSeparator());
+      sb.append(element.toString());
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("collection:");
+      sb.append(System.lineSeparator());
+      sb.append(collection.toString());
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/RemoveElementsOfComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/RemoveElementsOfComputation.java
new file mode 100644
index 0000000..66eb7a3
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/RemoveElementsOfComputation.java
@@ -0,0 +1,144 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.CollectionType;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class RemoveElementsOfComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:remove_all");
+      aliases.add("list:removeall");
+      aliases.add("list:removeAll");
+      aliases.add("set:remove_all");
+      aliases.add("set:removeall");
+      aliases.add("set:removeAll");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation other_collection;
+      final Computation collection;
+
+      if (call_parameters.size() != 2)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      other_collection = call_parameters.get(0);
+      collection = call_parameters.get(1);
+
+      other_collection.expect_non_string();
+      collection.expect_non_string();
+
+      if (alias.startsWith("set:"))
+      {
+         RecurrentChecks.assert_is_a_set(collection);
+      }
+      else
+      {
+         RecurrentChecks.assert_is_a_list(collection);
+      }
+
+      RecurrentChecks.assert_is_a_collection(other_collection);
+      RecurrentChecks.assert_can_be_used_as
+      (
+         other_collection.get_origin(),
+         ((CollectionType) other_collection.get_type()).get_content_type(),
+         ((CollectionType) collection.get_type()).get_content_type()
+      );
+
+      return
+         new RemoveElementsOfComputation(origin, other_collection, collection);
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Computation other_collection;
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected RemoveElementsOfComputation
+   (
+      final Origin origin,
+      final Computation other_collection,
+      final Computation collection
+   )
+   {
+      super(origin, collection.get_type());
+
+      this.collection = collection;
+      this.other_collection = other_collection;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_source_collection ()
+   {
+      return other_collection;
+   }
+
+   public Computation get_target_collection ()
+   {
+      return collection;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(RemoveElementsOf");
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("other_collection:");
+      sb.append(System.lineSeparator());
+      sb.append(other_collection.toString());
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("collection:");
+      sb.append(System.lineSeparator());
+      sb.append(collection.toString());
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/ReverseListComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/ReverseListComputation.java
new file mode 100644
index 0000000..5df91d0
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/ReverseListComputation.java
@@ -0,0 +1,122 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.CollectionType;
+import tonkadur.fate.v1.lang.type.Type;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class ReverseListComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:reverse");
+      aliases.add("set:reverse");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation collection;
+
+      if (call_parameters.size() != 1)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      collection = call_parameters.get(0);
+
+      collection.expect_non_string();
+
+      if (alias.startsWith("set:"))
+      {
+         RecurrentChecks.assert_is_a_set(collection);
+      }
+      else
+      {
+         RecurrentChecks.assert_is_a_list(collection);
+      }
+
+      return
+         new ReverseListComputation
+         (
+            origin,
+            collection,
+            CollectionType.build
+            (
+               origin,
+               (((CollectionType) collection.get_type()).get_content_type()),
+               false,
+               "auto generated"
+            )
+         );
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected ReverseListComputation
+   (
+      final Origin origin,
+      final Computation collection,
+      final Type result_type
+   )
+   {
+      super(origin, result_type);
+
+      this.collection = collection;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(ReverseList ");
+      sb.append(collection.toString());
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/ShuffleComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/ShuffleComputation.java
new file mode 100644
index 0000000..f5ed5a6
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/ShuffleComputation.java
@@ -0,0 +1,122 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.CollectionType;
+import tonkadur.fate.v1.lang.type.Type;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class ShuffleComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:shuffle");
+      aliases.add("set:shuffle");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation collection;
+
+      if (call_parameters.size() != 1)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      collection = call_parameters.get(0);
+
+      collection.expect_non_string();
+
+      if (alias.startsWith("set:"))
+      {
+         RecurrentChecks.assert_is_a_set(collection);
+      }
+      else
+      {
+         RecurrentChecks.assert_is_a_list(collection);
+      }
+
+      return
+         new ShuffleComputation
+         (
+            origin,
+            collection,
+            CollectionType.build
+            (
+               origin,
+               (((CollectionType) collection.get_type()).get_content_type()),
+               false,
+               "auto generated"
+            )
+         );
+   }
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected ShuffleComputation
+   (
+      final Origin origin,
+      final Computation collection,
+      final Type result_type
+   )
+   {
+      super(origin, result_type);
+
+      this.collection = collection;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(Shuffle ");
+      sb.append(collection.toString());
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/SizeOperator.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/SizeOperator.java
new file mode 100644
index 0000000..92b71df
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/SizeOperator.java
@@ -0,0 +1,115 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.Type;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class SizeOperator extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:length");
+      aliases.add("list:size");
+      aliases.add("set:length");
+      aliases.add("set:size");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation collection;
+
+      if (call_parameters.size() != 1)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      collection = call_parameters.get(0);
+
+      collection.expect_non_string();
+
+      if (alias.startsWith("set:"))
+      {
+         RecurrentChecks.assert_is_a_set(collection);
+      }
+      else
+      {
+         RecurrentChecks.assert_is_a_list(collection);
+      }
+
+      return new SizeOperator(origin, collection);
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected SizeOperator
+   (
+      final Origin origin,
+      final Computation collection
+   )
+   {
+      super(origin, Type.INT);
+
+      this.collection = collection;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(SizeOperator");
+      sb.append(System.lineSeparator());
+      sb.append(System.lineSeparator());
+
+      sb.append("collection:");
+      sb.append(System.lineSeparator());
+      sb.append(collection.toString());
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/SortComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/SortComputation.java
new file mode 100644
index 0000000..8e004d2
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/SortComputation.java
@@ -0,0 +1,136 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.Type;
+import tonkadur.fate.v1.lang.type.CollectionType;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class SortComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:sort");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      // TODO: implement
+      final Computation lambda_function = null;
+      final Computation collection = null;
+      final List<Computation> extra_params = null;
+      final List<Type> types_in;
+
+      types_in = new ArrayList<Type>();
+
+      RecurrentChecks.assert_is_a_list(collection);
+
+      types_in.add(((CollectionType) collection.get_type()).get_content_type());
+      types_in.add(types_in.get(0));
+
+      for (final Computation c: extra_params)
+      {
+         types_in.add(c.get_type());
+      }
+
+      RecurrentChecks.assert_lambda_matches_types
+      (
+         lambda_function,
+         Type.INT,
+         types_in
+      );
+
+      return
+         new SortComputation(origin, lambda_function, collection, extra_params);
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final List<Computation> extra_params;
+   protected final Computation lambda_function;
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected SortComputation
+   (
+      final Origin origin,
+      final Computation lambda_function,
+      final Computation collection,
+      final List<Computation> extra_params
+   )
+   {
+      super(origin, collection.get_type());
+
+      this.lambda_function = lambda_function;
+      this.collection = collection;
+      this.extra_params = extra_params;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_lambda_function ()
+   {
+      return lambda_function;
+   }
+
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(Sort ");
+      sb.append(lambda_function.toString());
+      sb.append(" ");
+      sb.append(collection.toString());
+
+      for (final Computation c: extra_params)
+      {
+         sb.append(" ");
+         sb.append(c.toString());
+      }
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/SubListComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/SubListComputation.java
new file mode 100644
index 0000000..f9c20bf
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/SubListComputation.java
@@ -0,0 +1,133 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.type.Type;
+
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+public class SubListComputation extends GenericComputation
+{
+   public static Collection<String> get_aliases ()
+   {
+      final Collection<String> aliases;
+
+      aliases = new ArrayList<String>();
+
+      aliases.add("list:sublist");
+      aliases.add("list:sub_list");
+      aliases.add("list:subList");
+      aliases.add("set:subset");
+      aliases.add("set:sub_set");
+      aliases.add("set:subList");
+
+      return aliases;
+   }
+
+   public static GenericComputation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Computation start;
+      final Computation end;
+      final Computation collection;
+
+      if (call_parameters.size() != 3)
+      {
+         // TODO: Error.
+         System.err.println("Wrong number of params at " + origin.toString());
+
+         return null;
+      }
+
+      start = call_parameters.get(0);
+      end = call_parameters.get(1);
+      collection = call_parameters.get(2);
+
+      start.expect_non_string();
+      end.expect_non_string();
+      collection.expect_non_string();
+
+      RecurrentChecks.assert_can_be_used_as(start, Type.INT);
+      RecurrentChecks.assert_can_be_used_as(end, Type.INT);
+      RecurrentChecks.assert_is_a_collection(collection);
+
+      return new SubListComputation(origin, start, end, collection);
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Computation start;
+   protected final Computation end;
+   protected final Computation collection;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected SubListComputation
+   (
+      final Origin origin,
+      final Computation start,
+      final Computation end,
+      final Computation collection
+   )
+   {
+      super(origin, collection.get_type());
+
+      this.start = start;
+      this.end = end;
+      this.collection = collection;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Accessors ************************************************************/
+   public Computation get_collection ()
+   {
+      return collection;
+   }
+
+   public Computation get_start_index ()
+   {
+      return start;
+   }
+
+   public Computation get_end_index ()
+   {
+      return end;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(SubList ");
+      sb.append(start.toString());
+      sb.append(" ");
+      sb.append(end.toString());
+      sb.append(" ");
+      sb.append(collection.toString());
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/meta/RecurrentChecks.java b/src/core/src/tonkadur/fate/v1/lang/meta/RecurrentChecks.java
index 40a85bb..ae905ef 100644
--- a/src/core/src/tonkadur/fate/v1/lang/meta/RecurrentChecks.java
+++ b/src/core/src/tonkadur/fate/v1/lang/meta/RecurrentChecks.java
@@ -160,20 +160,24 @@ public class RecurrentChecks
       }
    }
 
-   public static void assert_is_a_list_of
+   public static void propagate_expected_types_and_assert_is_a_list_of
    (
       final Computation c,
       final Computation e
    )
    throws ParsingError
    {
-      assert_is_a_list_of
-      (
-         c.get_origin(),
-         c.get_type(),
-         e.get_origin(),
-         e.get_type()
-      );
+      final Type content_type;
+
+      c.expect_non_string();
+
+      assert_is_a_list(c);
+
+      content_type = ((CollectionType) c.get_type()).get_content_type();
+
+      handle_expected_type_propagation(e, content_type);
+
+      assert_can_be_used_as(e, content_type);
    }
 
    public static void assert_is_a_list_of
@@ -194,20 +198,24 @@ public class RecurrentChecks
       );
    }
 
-   public static void assert_is_a_set_of
+   public static void propagate_expected_types_and_assert_is_a_set_of
    (
       final Computation c,
       final Computation e
    )
    throws ParsingError
    {
-      assert_is_a_set_of
-      (
-         c.get_origin(),
-         c.get_type(),
-         e.get_origin(),
-         e.get_type()
-      );
+      final Type content_type;
+
+      c.expect_non_string();
+
+      assert_is_a_set(c);
+
+      content_type = ((CollectionType) c.get_type()).get_content_type();
+
+      handle_expected_type_propagation(e, content_type);
+
+      assert_can_be_used_as(e, content_type);
    }
 
    public static void assert_is_a_set_of
@@ -228,23 +236,59 @@ public class RecurrentChecks
       );
    }
 
-   public static void assert_is_a_collection_of
+   public static void assert_is_a_set_of (final Computation c, final Type e)
+   throws ParsingError
+   {
+      assert_can_be_used_as
+      (
+         c,
+         CollectionType.build
+         (
+            c.get_origin(),
+            e,
+            true,
+            "RecurrentChecks is_a_set_of test type"
+         )
+      );
+   }
+
+   public static void assert_is_a_list_of (final Computation c, final Type e)
+   throws ParsingError
+   {
+      assert_can_be_used_as
+      (
+         c,
+         CollectionType.build
+         (
+            c.get_origin(),
+            e,
+            false,
+            "RecurrentChecks is_a_set_of test type"
+         )
+      );
+   }
+
+   public static void propagate_expected_types_and_assert_is_a_collection_of
    (
       final Computation c,
       final Computation e
    )
    throws ParsingError
    {
-      assert_is_a_collection_of
-      (
-         c.get_origin(),
-         c.get_type(),
-         e.get_origin(),
-         e.get_type()
-      );
+      final Type content_type;
+
+      c.expect_non_string();
+
+      assert_is_a_collection(c);
+
+      content_type = ((CollectionType) c.get_type()).get_content_type();
+
+      handle_expected_type_propagation(e, content_type);
+
+      assert_can_be_used_as(e, content_type);
    }
 
-   public static void assert_is_a_collection_of
+   public static void propagate_expected_types_and_assert_is_a_collection_of
    (
       final Origin oc,
       final Type c,
@@ -262,7 +306,8 @@ public class RecurrentChecks
       );
    }
 
-   public static void assert_computations_matches_signature
+   public static void
+   propagate_expected_types_and_assert_computations_matches_signature
    (
       final Origin o,
       final List<Computation> c,
@@ -292,6 +337,7 @@ public class RecurrentChecks
             public Boolean risky_lambda (final Type t, final Computation p)
             throws ParsingError
             {
+               handle_expected_type_propagation(p, t);
                assert_can_be_used_as(p, t);
 
                return Boolean.TRUE;
@@ -463,7 +509,8 @@ public class RecurrentChecks
       }
    }
 
-   public static void assert_lambda_matches_computations
+   public static void
+   propagate_expected_types_and_assert_lambda_matches_computations
    (
       final Computation l,
       final Type r,
@@ -471,9 +518,11 @@ public class RecurrentChecks
    )
    throws ParsingError
    {
+      l.expect_non_string();
+
       assert_is_a_lambda_function(l);
       assert_return_type_is(l, r);
-      assert_computations_matches_signature
+      propagate_expected_types_and_assert_computations_matches_signature
       (
          l.get_origin(),
          c,
@@ -481,15 +530,18 @@ public class RecurrentChecks
       );
    }
 
-   public static void assert_lambda_matches_computations
+   public static void
+   propagate_expected_types_and_assert_lambda_matches_computations
    (
       final Computation l,
       final List<Computation> c
    )
    throws ParsingError
    {
+      l.expect_non_string();
+
       assert_is_a_lambda_function(l);
-      assert_computations_matches_signature
+      propagate_expected_types_and_assert_computations_matches_signature
       (
          l.get_origin(),
          c,
diff --git a/src/core/src/tonkadur/wyrd/v1/compiler/fate/v1/ComputationCompiler.java b/src/core/src/tonkadur/wyrd/v1/compiler/fate/v1/ComputationCompiler.java
index 84b0ebc..f5bb4a0 100644
--- a/src/core/src/tonkadur/wyrd/v1/compiler/fate/v1/ComputationCompiler.java
+++ b/src/core/src/tonkadur/wyrd/v1/compiler/fate/v1/ComputationCompiler.java
@@ -1281,113 +1281,6 @@ implements tonkadur.fate.v1.lang.meta.ComputationVisitor
       result_as_computation = new Size(cc.get_address());
    }
 */
-/*
-   @Override
-   public void visit_text_join
-   (
-      final tonkadur.fate.v1.lang.computation.TextJoin n
-   )
-   throws Throwable
-   {
-      final Register i, collection_size, accumulator;
-      final List<Instruction> while_body;
-      final List<Computation> next_chain;
-      final ComputationCompiler link_cc, collection_cc;
-
-      link_cc = new ComputationCompiler(compiler);
-      collection_cc = new ComputationCompiler(compiler);
-
-      n.get_link().get_visited_by(link_cc);
-      n.get_text_collection().get_visited_by(collection_cc);
-
-      assimilate(link_cc);
-      assimilate(collection_cc);
-
-      next_chain = new ArrayList<Computation>();
-      while_body = new ArrayList<Instruction>();
-
-      i = reserve(Type.INT);
-      collection_size = reserve(Type.INT);
-      accumulator = reserve(Type.TEXT);
-
-      init_instructions.add
-      (
-         new SetValue(i.get_address(), Constant.ONE)
-      );
-      init_instructions.add
-      (
-         new SetValue
-         (
-            collection_size.get_address(),
-            new Size(collection_cc.get_address())
-         )
-      );
-
-      init_instructions.add
-      (
-         new SetValue
-         (
-            accumulator.get_address(),
-            new IfElseComputation
-            (
-               Operation.equals(collection_size.get_value(), Constant.ZERO),
-               new Text(new ArrayList<Computation>()),
-               new ValueOf
-               (
-                  new RelativeAddress
-                  (
-                     collection_cc.get_address(),
-                     new Cast(Constant.ZERO, Type.STRING),
-                     Type.TEXT
-                  )
-               )
-            )
-         )
-      );
-
-      next_chain.add(accumulator.get_value());
-      next_chain.add(link_cc.get_computation());
-      next_chain.add
-      (
-         new ValueOf
-         (
-            new RelativeAddress
-            (
-               collection_cc.get_address(),
-               new Cast(i.get_value(), Type.STRING),
-               Type.TEXT
-            )
-         )
-      );
-
-      while_body.add
-      (
-         new SetValue(accumulator.get_address(), new Text(next_chain))
-      );
-
-      while_body.add
-      (
-         new SetValue
-         (
-            i.get_address(),
-            Operation.plus(i.get_value(), Constant.ONE)
-         )
-      );
-
-      init_instructions.add
-      (
-         While.generate
-         (
-            compiler.registers(),
-            compiler.assembler(),
-            Operation.less_than(i.get_value(), collection_size.get_value()),
-            compiler.assembler().merge(while_body)
-         )
-      );
-
-      result_as_computation = accumulator.get_value();
-   }
-*/
    @Override
    public void visit_extra_computation
    (
diff --git a/src/core/src/tonkadur/wyrd/v1/compiler/fate/v1/computation/generic/TextJoinCompiler.java b/src/core/src/tonkadur/wyrd/v1/compiler/fate/v1/computation/generic/TextJoinCompiler.java
new file mode 100644
index 0000000..38fb3a3
--- /dev/null
+++ b/src/core/src/tonkadur/wyrd/v1/compiler/fate/v1/computation/generic/TextJoinCompiler.java
@@ -0,0 +1,153 @@
+package tonkadur.wyrd.v1.compiler.fate.v1.computation.generic;
+
+import java.util.List;
+import java.util.ArrayList;
+
+import tonkadur.fate.v1.lang.computation.generic.TextJoin;
+
+import tonkadur.wyrd.v1.lang.Register;
+
+import tonkadur.wyrd.v1.lang.meta.Computation;
+import tonkadur.wyrd.v1.lang.meta.Instruction;
+
+import tonkadur.wyrd.v1.lang.computation.Address;
+import tonkadur.wyrd.v1.lang.computation.Cast;
+import tonkadur.wyrd.v1.lang.computation.Constant;
+import tonkadur.wyrd.v1.lang.computation.IfElseComputation;
+import tonkadur.wyrd.v1.lang.computation.Operation;
+import tonkadur.wyrd.v1.lang.computation.RelativeAddress;
+import tonkadur.wyrd.v1.lang.computation.Size;
+import tonkadur.wyrd.v1.lang.computation.Text;
+import tonkadur.wyrd.v1.lang.computation.ValueOf;
+
+import tonkadur.wyrd.v1.lang.instruction.SetValue;
+
+import tonkadur.wyrd.v1.lang.type.Type;
+
+import tonkadur.wyrd.v1.compiler.fate.v1.Compiler;
+import tonkadur.wyrd.v1.compiler.fate.v1.TypeCompiler;
+import tonkadur.wyrd.v1.compiler.fate.v1.ComputationCompiler;
+
+import tonkadur.wyrd.v1.compiler.fate.v1.computation.GenericComputationCompiler;
+
+
+public class TextJoinCompiler extends GenericComputationCompiler
+{
+   public static Class get_target_class ()
+   {
+      return TextJoin.class;
+   }
+
+   public TextJoinCompiler (final Compiler compiler)
+   {
+      super(compiler);
+   }
+
+   public void compile
+   (
+      final tonkadur.fate.v1.lang.computation.GenericComputation computation
+   )
+   throws Throwable
+   {
+      final TextJoin source;
+      final Register i, collection_size, accumulator;
+      final List<Instruction> while_body;
+      final List<Computation> next_chain;
+      final ComputationCompiler link_cc, collection_cc;
+
+      source = (TextJoin) computation;
+
+      link_cc = new ComputationCompiler(compiler);
+      collection_cc = new ComputationCompiler(compiler);
+
+      source.get_link().get_visited_by(link_cc);
+      source.get_text_collection().get_visited_by(collection_cc);
+
+      assimilate(link_cc);
+      assimilate(collection_cc);
+
+      next_chain = new ArrayList<Computation>();
+      while_body = new ArrayList<Instruction>();
+
+      i = reserve(Type.INT);
+      collection_size = reserve(Type.INT);
+      accumulator = reserve(Type.TEXT);
+
+      init_instructions.add
+      (
+         new SetValue(i.get_address(), Constant.ONE)
+      );
+      init_instructions.add
+      (
+         new SetValue
+         (
+            collection_size.get_address(),
+            new Size(collection_cc.get_address())
+         )
+      );
+
+      init_instructions.add
+      (
+         new SetValue
+         (
+            accumulator.get_address(),
+            new IfElseComputation
+            (
+               Operation.equals(collection_size.get_value(), Constant.ZERO),
+               new Text(new ArrayList<Computation>()),
+               new ValueOf
+               (
+                  new RelativeAddress
+                  (
+                     collection_cc.get_address(),
+                     new Cast(Constant.ZERO, Type.STRING),
+                     Type.TEXT
+                  )
+               )
+            )
+         )
+      );
+
+      next_chain.add(accumulator.get_value());
+      next_chain.add(link_cc.get_computation());
+      next_chain.add
+      (
+         new ValueOf
+         (
+            new RelativeAddress
+            (
+               collection_cc.get_address(),
+               new Cast(i.get_value(), Type.STRING),
+               Type.TEXT
+            )
+         )
+      );
+
+      while_body.add
+      (
+         new SetValue(accumulator.get_address(), new Text(next_chain))
+      );
+
+      while_body.add
+      (
+         new SetValue
+         (
+            i.get_address(),
+            Operation.plus(i.get_value(), Constant.ONE)
+         )
+      );
+
+      init_instructions.add
+      (
+         tonkadur.wyrd.v1.compiler.util.While.generate
+         (
+            compiler.registers(),
+            compiler.assembler(),
+            Operation.less_than(i.get_value(), collection_size.get_value()),
+            compiler.assembler().merge(while_body)
+         )
+      );
+
+      result_as_computation = accumulator.get_value();
+   }
+}