...

17 files changed, 784 insertions, 600 deletions

diff --git a/src/core/src/tonkadur/fate/v1/lang/World.java b/src/core/src/tonkadur/fate/v1/lang/World.java
index 8355a2e..846ead8 100644
--- a/src/core/src/tonkadur/fate/v1/lang/World.java
+++ b/src/core/src/tonkadur/fate/v1/lang/World.java
@@ -20,8 +20,6 @@ import tonkadur.fate.v1.error.UnknownSequenceException;
 
 import tonkadur.fate.v1.lang.meta.Computation;
 import tonkadur.fate.v1.lang.meta.DeclarationCollection;
-import tonkadur.fate.v1.lang.meta.ExtraInstruction;
-import tonkadur.fate.v1.lang.meta.ExtraComputation;
 import tonkadur.fate.v1.lang.meta.RecurrentChecks;
 import tonkadur.fate.v1.lang.meta.Instruction;
 
@@ -47,8 +45,6 @@ public class World
       sequence_uses;
    protected final Map<String, List<SequenceReference>> sequence_variables;
 
-   protected final DeclarationCollection<ExtraInstruction> ei_collection;
-   protected final DeclarationCollection<ExtraComputation> ec_collection;
    protected final DeclarationCollection<Event> event_collection;
    protected final DeclarationCollection<Sequence> sequence_collection;
    protected final DeclarationCollection<TextEffect> text_effect_collection;
@@ -72,17 +68,6 @@ public class World
 
       sequence_variables = new HashMap<String, List<SequenceReference>>();
 
-      ei_collection =
-         new DeclarationCollection<ExtraInstruction>
-         (
-            ExtraInstruction.value_on_missing()
-         );
-      ec_collection =
-         new DeclarationCollection<ExtraComputation>
-         (
-            ExtraComputation.value_on_missing()
-         );
-
       event_collection =
          new DeclarationCollection<Event>(Event.value_on_missing());
       sequence_collection = new DeclarationCollection<Sequence>(null);
@@ -171,16 +156,6 @@ public class World
    }
 
    /**** Collections ****/
-   public DeclarationCollection<ExtraInstruction> extra_instructions ()
-   {
-      return ei_collection;
-   }
-
-   public DeclarationCollection<ExtraComputation> extra_computations ()
-   {
-      return ec_collection;
-   }
-
    public DeclarationCollection<Event> events ()
    {
       return event_collection;
@@ -260,20 +235,6 @@ public class World
       }
 
       sb.append(System.lineSeparator());
-      sb.append("Extra Instructions:");
-      sb.append(System.lineSeparator());
-      sb.append(ei_collection.toString());
-      sb.append(System.lineSeparator());
-      sb.append(System.lineSeparator());
-
-      sb.append(System.lineSeparator());
-      sb.append("Extra Computations:");
-      sb.append(System.lineSeparator());
-      sb.append(ec_collection.toString());
-      sb.append(System.lineSeparator());
-      sb.append(System.lineSeparator());
-
-      sb.append(System.lineSeparator());
       sb.append("Events:");
       sb.append(System.lineSeparator());
       sb.append(event_collection.toString());
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/ExtraComputationInstance.java b/src/core/src/tonkadur/fate/v1/lang/computation/ExtraComputationInstance.java
deleted file mode 100644
index 83960b7..0000000
--- a/src/core/src/tonkadur/fate/v1/lang/computation/ExtraComputationInstance.java
+++ /dev/null
@@ -1,97 +0,0 @@
-package tonkadur.fate.v1.lang.computation;
-
-import java.util.List;
-
-import tonkadur.parser.Context;
-import tonkadur.parser.Origin;
-import tonkadur.parser.ParsingError;
-
-import tonkadur.fate.v1.lang.meta.Computation;
-import tonkadur.fate.v1.lang.meta.ComputationVisitor;
-import tonkadur.fate.v1.lang.meta.ExtraComputation;
-import tonkadur.fate.v1.lang.meta.RecurrentChecks;
-
-public class ExtraComputationInstance extends Computation
-{
-   protected final ExtraComputation computation;
-   protected final List<Computation> parameters;
-
-   /***************************************************************************/
-   /**** PROTECTED ************************************************************/
-   /***************************************************************************/
-   /**** Constructors *********************************************************/
-   protected ExtraComputationInstance
-   (
-      final Origin origin,
-      final ExtraComputation computation,
-      final List<Computation> parameters
-   )
-   {
-      super(origin, computation.get_returned_type());
-
-      this.computation = computation;
-      this.parameters = parameters;
-   }
-
-   /***************************************************************************/
-   /**** PUBLIC ***************************************************************/
-   /***************************************************************************/
-   /**** Constructors *********************************************************/
-   public static ExtraComputationInstance build
-   (
-      final Origin origin,
-      final ExtraComputation computation,
-      final List<Computation> parameters
-   )
-   throws ParsingError
-   {
-      RecurrentChecks.propagate_expected_types_and_assert_computations_matches_signature
-      (
-         origin,
-         parameters,
-         computation.get_signature()
-      );
-
-      return new ExtraComputationInstance(origin, computation, parameters);
-   }
-
-   /**** Accessors ************************************************************/
-   public ExtraComputation get_computation_type ()
-   {
-      return computation;
-   }
-
-   public List<Computation> get_parameters ()
-   {
-      return parameters;
-   }
-
-   @Override
-   public void get_visited_by (final ComputationVisitor cv)
-   throws Throwable
-   {
-      cv.visit_extra_computation(this);
-   }
-
-   /**** Misc. ****************************************************************/
-   @Override
-   public String toString ()
-   {
-      final StringBuilder sb;
-
-      sb = new StringBuilder();
-
-      sb.append("(");
-      sb.append(computation.get_name());
-
-      for (final Computation p: parameters)
-      {
-         sb.append(" ");
-         sb.append(p.toString());
-      }
-
-      sb.append(")");
-
-      return sb.toString();
-   }
-}
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/GenericComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/GenericComputation.java
index 4f50166..25e541b 100644
--- a/src/core/src/tonkadur/fate/v1/lang/computation/GenericComputation.java
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/GenericComputation.java
@@ -86,6 +86,50 @@ public abstract class GenericComputation extends Computation
       }
    }
 
+   public static void register (final String alias, final Class c)
+   {
+      try
+      {
+         final Class previous_entry;
+
+         previous_entry = REGISTERED.get(alias);
+
+         if (previous_entry != null)
+         {
+            ErrorManager.handle
+            (
+               new BasicError
+               (
+                  ErrorLevel.FATAL,
+                  ErrorCategory.PROGRAMMING_ERROR,
+                  (
+                     "Unable to add alias for Generic Fate Computation '"
+                     + alias
+                     + "' from class '"
+                     + c.getName()
+                     + "': it has already been claimed by class '"
+                     + previous_entry.getName()
+                     + "'."
+                  )
+               )
+            );
+         }
+
+         REGISTERED.put(alias, c);
+      }
+      catch (final Throwable t)
+      {
+         System.err.println
+         (
+            "Could not register Generic Fate Computation class '"
+            + c.getName()
+            + "': "
+         );
+
+         t.printStackTrace();
+      }
+   }
+
    public static Computation build
    (
       final Origin origin,
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/ExtraComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/ExtraComputation.java
new file mode 100644
index 0000000..578200b
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/ExtraComputation.java
@@ -0,0 +1,151 @@
+package tonkadur.fate.v1.lang.computation.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import tonkadur.functional.Cons;
+
+import tonkadur.parser.Context;
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.ComputationVisitor;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.computation.GenericComputation;
+
+import tonkadur.fate.v1.lang.type.Type;
+
+public class ExtraComputation extends GenericComputation
+{
+   protected static final Map<String, Cons<Type, List<Type>>> SIGNATURES;
+
+   static
+   {
+      SIGNATURES = new HashMap<String, Cons<Type, List<Type>>>();
+   }
+
+   public static Collection<String> get_aliases ()
+   {
+      // These are added individually later.
+      return new ArrayList<String>();
+   }
+
+   public static void register
+   (
+      final Type return_type,
+      final String name,
+      final List<Type> signature
+   )
+   {
+      GenericComputation.register(name, ExtraComputation.class);
+
+      SIGNATURES.put(name, new Cons(return_type, signature));
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final String computation_name;
+   protected final List<Computation> parameters;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected ExtraComputation
+   (
+      final Origin origin,
+      final Type return_type,
+      final String computation_name,
+      final List<Computation> parameters
+   )
+   {
+      super(origin, return_type);
+
+      this.computation_name = computation_name;
+      this.parameters = parameters;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   public static Computation build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Cons<Type, List<Type>> signature;
+
+      signature = SIGNATURES.get(alias);
+
+      if (signature == null)
+      {
+         System.err.println(origin.toString());
+         System.err.println
+         (
+            "[F] Programming error: the Extra Computation'"
+            + alias
+            + "' was registered without a signature."
+         );
+         System.exit(-1);
+      }
+
+      RecurrentChecks.propagate_expected_types_and_assert_computations_matches_signature
+      (
+         origin,
+         call_parameters,
+         signature.get_cdr()
+      );
+
+      return
+         new ExtraComputation
+         (
+            origin,
+            signature.get_car(),
+            alias,
+            call_parameters
+         );
+   }
+
+   /**** Accessors ************************************************************/
+   public String get_computation_name ()
+   {
+      return computation_name;
+   }
+
+   public List<Computation> get_parameters ()
+   {
+      return parameters;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb;
+
+      sb = new StringBuilder();
+
+      sb.append("(");
+      sb.append(get_computation_name());
+
+      for (final Computation p: parameters)
+      {
+         sb.append(" ");
+         sb.append(p.toString());
+      }
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/instruction/ExtraInstructionInstance.java b/src/core/src/tonkadur/fate/v1/lang/instruction/ExtraInstructionInstance.java
deleted file mode 100644
index efeafaa..0000000
--- a/src/core/src/tonkadur/fate/v1/lang/instruction/ExtraInstructionInstance.java
+++ /dev/null
@@ -1,98 +0,0 @@
-package tonkadur.fate.v1.lang.instruction;
-
-import java.util.List;
-
-import tonkadur.parser.Context;
-import tonkadur.parser.Origin;
-import tonkadur.parser.ParsingError;
-
-import tonkadur.fate.v1.lang.meta.Computation;
-import tonkadur.fate.v1.lang.meta.Instruction;
-import tonkadur.fate.v1.lang.meta.InstructionVisitor;
-import tonkadur.fate.v1.lang.meta.ExtraInstruction;
-import tonkadur.fate.v1.lang.meta.RecurrentChecks;
-
-public class ExtraInstructionInstance extends Instruction
-{
-   protected final ExtraInstruction instruction;
-   protected final List<Computation> parameters;
-
-   /***************************************************************************/
-   /**** PROTECTED ************************************************************/
-   /***************************************************************************/
-   /**** Constructors *********************************************************/
-   protected ExtraInstructionInstance
-   (
-      final Origin origin,
-      final ExtraInstruction instruction,
-      final List<Computation> parameters
-   )
-   {
-      super(origin);
-
-      this.instruction = instruction;
-      this.parameters = parameters;
-   }
-
-   /***************************************************************************/
-   /**** PUBLIC ***************************************************************/
-   /***************************************************************************/
-   /**** Constructors *********************************************************/
-   public static ExtraInstructionInstance build
-   (
-      final Origin origin,
-      final ExtraInstruction instruction,
-      final List<Computation> parameters
-   )
-   throws ParsingError
-   {
-      RecurrentChecks.propagate_expected_types_and_assert_computations_matches_signature
-      (
-         origin,
-         parameters,
-         instruction.get_signature()
-      );
-
-      return new ExtraInstructionInstance(origin, instruction, parameters);
-   }
-
-   /**** Accessors ************************************************************/
-   @Override
-   public void get_visited_by (final InstructionVisitor iv)
-   throws Throwable
-   {
-      iv.visit_extra_instruction(this);
-   }
-
-   public ExtraInstruction get_instruction_type ()
-   {
-      return instruction;
-   }
-
-   public List<Computation> get_parameters ()
-   {
-      return parameters;
-   }
-
-   /**** Misc. ****************************************************************/
-   @Override
-   public String toString ()
-   {
-      final StringBuilder sb;
-
-      sb = new StringBuilder();
-
-      sb.append("(");
-      sb.append(instruction.get_name());
-
-      for (final Computation p: parameters)
-      {
-         sb.append(" ");
-         sb.append(p.toString());
-      }
-
-      sb.append(")");
-
-      return sb.toString();
-   }
-}
diff --git a/src/core/src/tonkadur/fate/v1/lang/instruction/GenericInstruction.java b/src/core/src/tonkadur/fate/v1/lang/instruction/GenericInstruction.java
index 8c2b77e..ce75974 100644
--- a/src/core/src/tonkadur/fate/v1/lang/instruction/GenericInstruction.java
+++ b/src/core/src/tonkadur/fate/v1/lang/instruction/GenericInstruction.java
@@ -87,6 +87,50 @@ public abstract class GenericInstruction extends Instruction
       }
    }
 
+   public static void register (final String alias, final Class c)
+   {
+      try
+      {
+         final Class previous_entry;
+
+         previous_entry = REGISTERED.get(alias);
+
+         if (previous_entry != null)
+         {
+            ErrorManager.handle
+            (
+               new BasicError
+               (
+                  ErrorLevel.FATAL,
+                  ErrorCategory.PROGRAMMING_ERROR,
+                  (
+                     "Unable to add alias for Generic Fate Instruction '"
+                     + alias
+                     + "' from class '"
+                     + c.getName()
+                     + "': it has already been claimed by class '"
+                     + previous_entry.getName()
+                     + "'."
+                  )
+               )
+            );
+         }
+
+         REGISTERED.put(alias, c);
+      }
+      catch (final Throwable t)
+      {
+         System.err.println
+         (
+            "Could not register Generic Fate Instruction class '"
+            + c.getName()
+            + "': "
+         );
+
+         t.printStackTrace();
+      }
+   }
+
    public static Instruction build
    (
       final Origin origin,
diff --git a/src/core/src/tonkadur/fate/v1/lang/instruction/generic/ExtraInstruction.java b/src/core/src/tonkadur/fate/v1/lang/instruction/generic/ExtraInstruction.java
new file mode 100644
index 0000000..1ed6f1b
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/instruction/generic/ExtraInstruction.java
@@ -0,0 +1,137 @@
+package tonkadur.fate.v1.lang.instruction.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import tonkadur.parser.Context;
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.meta.Computation;
+import tonkadur.fate.v1.lang.meta.Instruction;
+import tonkadur.fate.v1.lang.meta.InstructionVisitor;
+import tonkadur.fate.v1.lang.meta.RecurrentChecks;
+
+import tonkadur.fate.v1.lang.instruction.GenericInstruction;
+
+import tonkadur.fate.v1.lang.type.Type;
+
+public class ExtraInstruction extends GenericInstruction
+{
+   protected static final Map<String, List<Type>> SIGNATURES;
+
+   static
+   {
+      SIGNATURES = new HashMap<String, List<Type>>();
+   }
+
+   public static Collection<String> get_aliases ()
+   {
+      // These are added individually later.
+      return new ArrayList<String>();
+   }
+
+   public static void register (final String name, final List<Type> signature)
+   {
+      GenericInstruction.register(name, ExtraInstruction.class);
+
+      SIGNATURES.put(name, signature);
+   }
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected ExtraInstruction
+   (
+      final Origin origin,
+      final String instruction_name,
+      final List<Computation> parameters
+   )
+   {
+      super(origin);
+
+      this.instruction_name = instruction_name;
+      this.parameters = parameters;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   public static Instruction build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final List<Type> signature;
+
+      signature = SIGNATURES.get(alias);
+
+      if (signature == null)
+      {
+         System.err.println(origin.toString());
+         System.err.println
+         (
+            "[F] Programming error: the Extra Instruction '"
+            + alias
+            + "' was registered without a signature."
+         );
+         System.exit(-1);
+      }
+
+      RecurrentChecks.propagate_expected_types_and_assert_computations_matches_signature
+      (
+         origin,
+         call_parameters,
+         signature
+      );
+
+      return new ExtraInstruction(origin, alias, call_parameters);
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final String instruction_name;
+   protected final List<Computation> parameters;
+
+   /**** Accessors ************************************************************/
+   public String get_instruction_name ()
+   {
+      return instruction_name;
+   }
+
+   public List<Computation> get_parameters ()
+   {
+      return parameters;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb;
+
+      sb = new StringBuilder();
+
+      sb.append("(");
+      sb.append(get_instruction_name());
+
+      for (final Computation p: get_parameters())
+      {
+         sb.append(" ");
+         sb.append(p.toString());
+      }
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/instruction/generic/UserInstruction.java b/src/core/src/tonkadur/fate/v1/lang/instruction/generic/UserInstruction.java
new file mode 100644
index 0000000..9c32c20
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/instruction/generic/UserInstruction.java
@@ -0,0 +1,135 @@
+package tonkadur.fate.v1.lang.instruction.generic;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import tonkadur.parser.Origin;
+
+import tonkadur.fate.v1.lang.Sequence;
+
+import tonkadur.fate.v1.lang.meta.Instruction;
+import tonkadur.fate.v1.lang.meta.Computation;
+
+import tonkadur.fate.v1.lang.instruction.GenericInstruction;
+
+public class UserInstruction extends GenericInstruction
+{
+   protected static final Map<String, Sequence> DEFINITIONS;
+
+   static
+   {
+      DEFINITIONS = new HashMap<String, Sequence>();
+   }
+
+   public static Collection<String> get_aliases ()
+   {
+      // Will be added individually later.
+      return new ArrayList<String>();
+   }
+
+   public static void register (final Sequence sequence)
+   {
+      GenericInstruction.register(sequence.get_name(), UserInstruction.class);
+
+      DEFINITIONS.put(sequence.get_name(), sequence);
+   }
+
+   public static Collection<Sequence> get_all_definitions ()
+   {
+      return DEFINITIONS.values();
+   }
+
+   public static Instruction build
+   (
+      final Origin origin,
+      final String alias,
+      final List<Computation> call_parameters
+   )
+   throws Throwable
+   {
+      final Sequence definition;
+
+      definition = DEFINITIONS.get(alias);
+
+      if (definition == null)
+      {
+         System.err.println(origin.toString());
+         System.err.println
+         (
+            "[F] Programming error: the User Instruction '"
+            + alias
+            + "' was registered without an associated Sequence."
+         );
+         System.exit(-1);
+      }
+
+      definition.propagate_expected_types_and_assert_can_take_parameters
+      (
+         origin,
+         call_parameters
+      );
+
+      return new UserInstruction(origin, definition, call_parameters);
+   }
+
+   /***************************************************************************/
+   /**** MEMBERS **************************************************************/
+   /***************************************************************************/
+   protected final Sequence definition;
+   protected final List<Computation> parameters;
+
+   /***************************************************************************/
+   /**** PROTECTED ************************************************************/
+   /***************************************************************************/
+   /**** Constructors *********************************************************/
+   protected UserInstruction
+   (
+      final Origin origin,
+      final Sequence definition,
+      final List<Computation> parameters
+   )
+   {
+      super(origin);
+
+      this.definition = definition;
+      this.parameters = parameters;
+   }
+
+   /***************************************************************************/
+   /**** PUBLIC ***************************************************************/
+   /***************************************************************************/
+
+   /**** Accessors ************************************************************/
+   public Sequence get_definition ()
+   {
+      return definition;
+   }
+
+   public List<Computation> get_parameters ()
+   {
+      return parameters;
+   }
+
+   /**** Misc. ****************************************************************/
+   @Override
+   public String toString ()
+   {
+      final StringBuilder sb = new StringBuilder();
+
+      sb.append("(");
+      sb.append(definition.get_name());
+
+      for (final Computation param: parameters)
+      {
+         sb.append(" ");
+         sb.append(param.toString());
+      }
+
+      sb.append(")");
+
+      return sb.toString();
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/lang/meta/ComputationVisitor.java b/src/core/src/tonkadur/fate/v1/lang/meta/ComputationVisitor.java
index 7f93acf..feb63ff 100644
--- a/src/core/src/tonkadur/fate/v1/lang/meta/ComputationVisitor.java
+++ b/src/core/src/tonkadur/fate/v1/lang/meta/ComputationVisitor.java
@@ -2,6 +2,8 @@ package tonkadur.fate.v1.lang.meta;
 
 import tonkadur.fate.v1.lang.computation.*;
 
+import tonkadur.fate.v1.lang.computation.generic.ExtraComputation;
+
 public interface ComputationVisitor
 {
    public void visit_field_access (final FieldAccess n)
@@ -46,9 +48,6 @@ public interface ComputationVisitor
    public void visit_set_fields (final SetFieldsComputation n)
    throws Throwable;
 
-   public void visit_extra_computation (final ExtraComputationInstance n)
-   throws Throwable;
-
    public void visit_generic_computation (final GenericComputation n)
    throws Throwable;
 }
diff --git a/src/core/src/tonkadur/fate/v1/lang/meta/ExtraComputation.java b/src/core/src/tonkadur/fate/v1/lang/meta/ExtraComputation.java
deleted file mode 100644
index f3a913e..0000000
--- a/src/core/src/tonkadur/fate/v1/lang/meta/ExtraComputation.java
+++ /dev/null
@@ -1,134 +0,0 @@
-package tonkadur.fate.v1.lang.meta;
-
-import java.util.ArrayList;
-import java.util.List;
-
-import tonkadur.parser.Context;
-import tonkadur.parser.Origin;
-import tonkadur.parser.ParsingError;
-
-import tonkadur.fate.v1.lang.World;
-
-import tonkadur.fate.v1.lang.type.Type;
-
-import tonkadur.fate.v1.lang.computation.ExtraComputationInstance;
-
-
-// This is for computations that are not compiled to Wyrd, but simply declared
-// in Fate and implemented by the wyrd interpreter.
-// This class should become something like a sub-GenericComputation thing.
-// Declaring an ExtraComputation should register an ExtraComputation object as a
-// GenericComputation, thus making it seamless from the user's point of view.
-public class ExtraComputation extends DeclaredEntity
-{
-   protected static final ExtraComputation ANY;
-
-   static
-   {
-      ANY =
-         new ExtraComputation
-         (
-            Origin.BASE_LANGUAGE,
-            Type.ANY,
-            /*
-             * Use of a space necessary to avoid conflicting with a user created
-             * type.
-             */
-            "undetermined extra_computation",
-            new ArrayList<Type>()
-         );
-   }
-
-   public static ExtraComputation value_on_missing ()
-   {
-      return ANY;
-   }
-
-   @Override
-   public /* static */ String get_type_name ()
-   {
-      return "ExtraComputation";
-   }
-
-   /***************************************************************************/
-   /**** MEMBERS **************************************************************/
-   /***************************************************************************/
-   protected final Type returned_type;
-   protected final List<Type> signature;
-
-   /***************************************************************************/
-   /**** PUBLIC ***************************************************************/
-   /***************************************************************************/
-   /**** Constructors *********************************************************/
-   public ExtraComputation
-   (
-      final Origin origin,
-      final Type returned_type,
-      final String name,
-      final List<Type> signature
-   )
-   {
-      super(origin, name);
-
-      this.returned_type = returned_type;
-      this.signature = signature;
-   }
-
-   public ExtraComputation
-   (
-      final Type returned_type,
-      final String name,
-      final List<Type> signature
-   )
-   {
-      super(Origin.BASE_LANGUAGE, name);
-
-      this.returned_type = returned_type;
-      this.signature = signature;
-   }
-
-   /**** Accessors ************************************************************/
-   public Type get_returned_type ()
-   {
-      return returned_type;
-   }
-
-   public List<Type> get_signature ()
-   {
-      return signature;
-   }
-
-   /**** Instantiating ********************************************************/
-   public ExtraComputationInstance instantiate
-   (
-      final World world,
-      final Context context,
-      final Origin origin,
-      final List<Computation> parameters
-   )
-   throws ParsingError
-   {
-      return ExtraComputationInstance.build(origin, this, parameters);
-   }
-
-   /**** Misc. ****************************************************************/
-   @Override
-   public String toString ()
-   {
-      final StringBuilder sb;
-
-      sb = new StringBuilder();
-
-      sb.append(returned_type.toString());
-      sb.append(" ");
-      sb.append(name);
-
-      for (final Type t: signature)
-      {
-         sb.append(" ");
-         sb.append(t.toString());
-      }
-
-      return name;
-   }
-}
diff --git a/src/core/src/tonkadur/fate/v1/lang/meta/ExtraInstruction.java b/src/core/src/tonkadur/fate/v1/lang/meta/ExtraInstruction.java
deleted file mode 100644
index cd056dd..0000000
--- a/src/core/src/tonkadur/fate/v1/lang/meta/ExtraInstruction.java
+++ /dev/null
@@ -1,115 +0,0 @@
-package tonkadur.fate.v1.lang.meta;
-
-import java.util.ArrayList;
-import java.util.List;
-
-import tonkadur.parser.Context;
-import tonkadur.parser.Origin;
-import tonkadur.parser.ParsingError;
-
-import tonkadur.fate.v1.lang.World;
-
-import tonkadur.fate.v1.lang.type.Type;
-
-import tonkadur.fate.v1.lang.instruction.ExtraInstructionInstance;
-
-public class ExtraInstruction extends DeclaredEntity
-{
-   protected static final ExtraInstruction ANY;
-
-   static
-   {
-      ANY =
-         new ExtraInstruction
-         (
-            Origin.BASE_LANGUAGE,
-            /*
-             * Use of a space necessary to avoid conflicting with a user created
-             * type.
-             */
-            "undetermined extra_instruction",
-            new ArrayList<Type>()
-         );
-   }
-
-   public static ExtraInstruction value_on_missing ()
-   {
-      return ANY;
-   }
-
-   @Override
-   public /* static */ String get_type_name ()
-   {
-      return "ExtraInstruction";
-   }
-
-   /***************************************************************************/
-   /**** MEMBERS **************************************************************/
-   /***************************************************************************/
-   protected final List<Type> signature;
-
-   /***************************************************************************/
-   /**** PUBLIC ***************************************************************/
-   /***************************************************************************/
-   /**** Constructors *********************************************************/
-   public ExtraInstruction
-   (
-      final Origin origin,
-      final String name,
-      final List<Type> signature
-   )
-   {
-      super(origin, name);
-
-      this.signature = signature;
-   }
-
-   public ExtraInstruction
-   (
-      final String name,
-      final List<Type> signature
-   )
-   {
-      super(Origin.BASE_LANGUAGE, name);
-
-      this.signature = signature;
-   }
-
-   /**** Accessors ************************************************************/
-   public List<Type> get_signature ()
-   {
-      return signature;
-   }
-
-   /**** Instantiating ********************************************************/
-   public ExtraInstructionInstance instantiate
-   (
-      final World world,
-      final Context context,
-      final Origin origin,
-      final List<Computation> parameters
-   )
-   throws ParsingError
-   {
-      return ExtraInstructionInstance.build(origin, this, parameters);
-   }
-
-   /**** Misc. ****************************************************************/
-   @Override
-   public String toString ()
-   {
-      final StringBuilder sb;
-
-      sb = new StringBuilder();
-
-      sb.append(name);
-
-      for (final Type t: signature)
-      {
-         sb.append(" ");
-         sb.append(t.toString());
-      }
-
-      return name;
-   }
-}
diff --git a/src/core/src/tonkadur/fate/v1/lang/meta/InstructionVisitor.java b/src/core/src/tonkadur/fate/v1/lang/meta/InstructionVisitor.java
index 521e850..33fae6b 100644
--- a/src/core/src/tonkadur/fate/v1/lang/meta/InstructionVisitor.java
+++ b/src/core/src/tonkadur/fate/v1/lang/meta/InstructionVisitor.java
@@ -2,6 +2,8 @@ package tonkadur.fate.v1.lang.meta;
 
 import tonkadur.fate.v1.lang.instruction.*;
 
+import tonkadur.fate.v1.lang.instruction.generic.ExtraInstruction;
+
 public interface InstructionVisitor
 {
    /* Instruction Nodes */
@@ -65,9 +67,6 @@ public interface InstructionVisitor
    public void visit_set_fields (final SetFields n)
    throws Throwable;
 
-   public void visit_extra_instruction (final ExtraInstructionInstance n)
-   throws Throwable;
-
    public void visit_generic_instruction (final GenericInstruction n)
    throws Throwable;
 }
diff --git a/src/core/src/tonkadur/fate/v1/parser/FateParser.g4 b/src/core/src/tonkadur/fate/v1/parser/FateParser.g4
index 62de7e0..a06487b 100644
--- a/src/core/src/tonkadur/fate/v1/parser/FateParser.g4
+++ b/src/core/src/tonkadur/fate/v1/parser/FateParser.g4
@@ -47,7 +47,10 @@ options
    import tonkadur.fate.v1.lang.type.*;
    import tonkadur.fate.v1.lang.computation.*;
 
+   import tonkadur.fate.v1.lang.computation.generic.ExtraComputation;
+
    import tonkadur.fate.v1.lang.instruction.generic.SetValue;
+   import tonkadur.fate.v1.lang.instruction.generic.ExtraInstruction;
 }
 
 @members
@@ -185,15 +188,11 @@ first_level_instruction
             ($DECLARE_EXTRA_INSTRUCTION_KW.getCharPositionInLine())
          );
 
-      extra_instruction =
-         new ExtraInstruction
-         (
-            start_origin,
-            ($identifier.result),
-            ($maybe_type_list.result)
-         );
-
-      PARSER.get_world().extra_instructions().add(extra_instruction);
+      ExtraInstruction.register
+      (
+         ($identifier.result),
+         ($maybe_type_list.result)
+      );
 
       RecurrentChecks.assert_has_user_content_prefix
       (
@@ -218,16 +217,12 @@ first_level_instruction
             ($DECLARE_EXTRA_COMPUTATION_KW.getCharPositionInLine())
          );
 
-      extra_computation =
-         new ExtraComputation
-         (
-            start_origin,
-            ($type.result),
-            ($identifier.result),
-            ($maybe_type_list.result)
-         );
-
-      PARSER.get_world().extra_computations().add(extra_computation);
+      ExtraComputation.register
+      (
+         ($type.result),
+         ($identifier.result),
+         ($maybe_type_list.result)
+      );
 
       RecurrentChecks.assert_has_user_content_prefix
       (
@@ -517,6 +512,114 @@ first_level_instruction
       PARSER.restore_local_variables_stack(previous_local_variables_stack);
    }
 
+   | DECLARE_INSTRUCTION_KW
+         {
+            previous_local_variables_stack = PARSER.get_local_variables_stack();
+            PARSER.discard_local_variables_stack();
+            PARSER.increase_local_variables_hierarchy();
+         }
+         identifier
+         WS*
+         (
+            L_PAREN WS* variable_list WS* R_PAREN
+            {
+               PARSER.add_local_variables(($variable_list.result).as_map());
+               PARSER.increase_local_variables_hierarchy();
+            }
+         )
+         pre_sequence_point=WS+
+         maybe_instruction_list
+         WS*
+      R_PAREN
+   {
+      final Origin start_origin, sequence_origin;
+      final Sequence new_sequence;
+
+      start_origin =
+         PARSER.get_origin_at
+         (
+            ($DECLARE_INSTRUCTION_KW.getLine()),
+            ($DECLARE_INSTRUCTION_KW.getCharPositionInLine())
+         );
+
+      sequence_origin =
+         PARSER.get_origin_at
+         (
+            ($pre_sequence_point.getLine()),
+            ($pre_sequence_point.getCharPositionInLine())
+         );
+
+      new_sequence =
+         new Sequence
+         (
+            start_origin,
+            new InstructionList
+            (
+               sequence_origin,
+               ($maybe_instruction_list.result)
+            ),
+            ($identifier.result),
+            ($variable_list.result).get_entries()
+         );
+
+      //PARSER.get_world().user_defined_instructions().add(new_sequence);
+      PARSER.restore_local_variables_stack(previous_local_variables_stack);
+
+      RecurrentChecks.assert_has_user_content_prefix
+      (
+         start_origin,
+         ($identifier.result)
+      );
+   }
+
+   | DECLARE_COMPUTATION_KW
+      {
+         previous_local_variables_stack = PARSER.get_local_variables_stack();
+         PARSER.discard_local_variables_stack();
+         PARSER.increase_local_variables_hierarchy();
+      }
+         identifier WS*
+         L_PAREN WS* variable_list WS* R_PAREN
+         {
+            PARSER.add_local_variables(($variable_list.result).as_map());
+         }
+         WS*
+         computation
+         WS*
+      R_PAREN
+      {
+         final Origin start_origin;
+         final LambdaExpression computation;
+
+         PARSER.restore_local_variables_stack(previous_local_variables_stack);
+
+         start_origin =
+            PARSER.get_origin_at
+            (
+               ($DECLARE_COMPUTATION_KW.getLine()),
+               ($DECLARE_COMPUTATION_KW.getCharPositionInLine())
+            );
+
+         computation =
+            LambdaExpression.build
+            (
+               start_origin,
+               ($variable_list.result).get_entries(),
+               ($computation.result)
+            );
+         /*
+         PARSER.get_world().user_defined_computations().add
+         (
+            ($identifier.result),
+            new_sequence
+         );
+         */
+         RecurrentChecks.assert_has_user_content_prefix
+         (
+            start_origin,
+            ($identifier.result)
+         );
+      }
 
    | IMP_IGNORE_ERROR_KW word WS+ first_level_instruction WS* R_PAREN
    {
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 b9f62e9..721f6d8 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
@@ -382,43 +382,6 @@ implements tonkadur.fate.v1.lang.meta.ComputationVisitor
    }
 
    @Override
-   public void visit_extra_computation
-   (
-      final tonkadur.fate.v1.lang.computation.ExtraComputationInstance n
-   )
-   throws Throwable
-   {
-      final List<Computation> parameters;
-
-      parameters = new ArrayList<Computation>();
-
-      for (final tonkadur.fate.v1.lang.meta.Computation p: n.get_parameters())
-      {
-         final ComputationCompiler cc;
-
-         cc = new ComputationCompiler(compiler);
-
-         p.get_visited_by(cc);
-
-         assimilate(cc);
-
-         parameters.add(cc.get_computation());
-      }
-
-      result_as_computation =
-         new ExtraComputation
-         (
-            TypeCompiler.compile
-            (
-               compiler,
-               n.get_computation_type().get_returned_type()
-            ),
-            n.get_computation_type().get_name(),
-            parameters
-         );
-   }
-
-   @Override
    public void visit_default
    (
       final tonkadur.fate.v1.lang.computation.Default n
diff --git a/src/core/src/tonkadur/wyrd/v1/compiler/fate/v1/InstructionCompiler.java b/src/core/src/tonkadur/wyrd/v1/compiler/fate/v1/InstructionCompiler.java
index cc30524..22767f0 100644
--- a/src/core/src/tonkadur/wyrd/v1/compiler/fate/v1/InstructionCompiler.java
+++ b/src/core/src/tonkadur/wyrd/v1/compiler/fate/v1/InstructionCompiler.java
@@ -34,7 +34,6 @@ import tonkadur.wyrd.v1.lang.instruction.AddEventOption;
 import tonkadur.wyrd.v1.lang.instruction.Assert;
 import tonkadur.wyrd.v1.lang.instruction.Display;
 import tonkadur.wyrd.v1.lang.instruction.End;
-import tonkadur.wyrd.v1.lang.instruction.ExtraInstruction;
 import tonkadur.wyrd.v1.lang.instruction.Initialize;
 import tonkadur.wyrd.v1.lang.instruction.PromptInteger;
 import tonkadur.wyrd.v1.lang.instruction.PromptString;
@@ -786,60 +785,6 @@ implements tonkadur.fate.v1.lang.meta.InstructionVisitor
    }
 
    @Override
-   public void visit_extra_instruction
-   (
-      final tonkadur.fate.v1.lang.instruction.ExtraInstructionInstance n
-   )
-   throws Throwable
-   {
-      /*
-       * Fate: (event_call <string> c0 ... cn)
-       *
-       * Wyrd (event_call <string> c0 ... cn)
-       */
-      final List<ComputationCompiler> cc_list;
-      final List<Computation> parameters;
-
-      cc_list = new ArrayList<ComputationCompiler>();
-      parameters = new ArrayList<Computation>();
-
-      for
-      (
-         final tonkadur.fate.v1.lang.meta.Computation fate_computation:
-            n.get_parameters()
-      )
-      {
-         final ComputationCompiler cc;
-
-         cc = new ComputationCompiler(compiler);
-
-         fate_computation.get_visited_by(cc);
-
-         if (cc.has_init())
-         {
-            result.add(cc.get_init());
-         }
-
-         cc_list.add(cc);
-         parameters.add(cc.get_computation());
-      }
-
-      result.add
-      (
-         new ExtraInstruction
-         (
-            n.get_instruction_type().get_name(),
-            parameters
-         )
-      );
-
-      for (final ComputationCompiler cc: cc_list)
-      {
-         cc.release_registers(result);
-      }
-   }
-
-   @Override
    public void visit_if_else_instruction
    (
       final tonkadur.fate.v1.lang.instruction.IfElseInstruction n
diff --git a/src/core/src/tonkadur/wyrd/v1/compiler/fate/v1/computation/generic/ExtraComputationCompiler.java b/src/core/src/tonkadur/wyrd/v1/compiler/fate/v1/computation/generic/ExtraComputationCompiler.java
new file mode 100644
index 0000000..660120a
--- /dev/null
+++ b/src/core/src/tonkadur/wyrd/v1/compiler/fate/v1/computation/generic/ExtraComputationCompiler.java
@@ -0,0 +1,65 @@
+package tonkadur.wyrd.v1.compiler.fate.v1.computation.generic;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import tonkadur.fate.v1.lang.computation.generic.ExtraComputation;
+
+import tonkadur.wyrd.v1.lang.meta.Computation;
+
+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 ExtraComputationCompiler extends GenericComputationCompiler
+{
+   public static Class get_target_class ()
+   {
+      return ExtraComputation.class;
+   }
+
+   public ExtraComputationCompiler (final Compiler compiler)
+   {
+      super(compiler);
+   }
+
+   public void compile
+   (
+      final tonkadur.fate.v1.lang.computation.GenericComputation computation
+   )
+   throws Throwable
+   {
+      final ExtraComputation source;
+      final List<Computation> parameters;
+
+      source = (ExtraComputation) computation;
+
+      parameters = new ArrayList<Computation>();
+
+      for
+      (
+         final tonkadur.fate.v1.lang.meta.Computation p: source.get_parameters()
+      )
+      {
+         final ComputationCompiler cc;
+
+         cc = new ComputationCompiler(compiler);
+
+         p.get_visited_by(cc);
+
+         assimilate(cc);
+
+         parameters.add(cc.get_computation());
+      }
+
+      result_as_computation =
+         new tonkadur.wyrd.v1.lang.computation.ExtraComputation
+         (
+            TypeCompiler.compile(compiler, source.get_type()),
+            source.get_computation_name(),
+            parameters
+         );
+   }
+}
diff --git a/src/core/src/tonkadur/wyrd/v1/compiler/fate/v1/instruction/generic/ExtraInstructionCompiler.java b/src/core/src/tonkadur/wyrd/v1/compiler/fate/v1/instruction/generic/ExtraInstructionCompiler.java
new file mode 100644
index 0000000..7d87068
--- /dev/null
+++ b/src/core/src/tonkadur/wyrd/v1/compiler/fate/v1/instruction/generic/ExtraInstructionCompiler.java
@@ -0,0 +1,82 @@
+package tonkadur.wyrd.v1.compiler.fate.v1.instruction.generic;
+
+import java.util.List;
+import java.util.ArrayList;
+
+import tonkadur.fate.v1.lang.instruction.generic.ExtraInstruction;
+
+import tonkadur.wyrd.v1.lang.meta.Computation;
+
+import tonkadur.wyrd.v1.compiler.fate.v1.Compiler;
+import tonkadur.wyrd.v1.compiler.fate.v1.ComputationCompiler;
+
+import tonkadur.wyrd.v1.compiler.fate.v1.instruction.GenericInstructionCompiler;
+
+public class ExtraInstructionCompiler extends GenericInstructionCompiler
+{
+   public static Class get_target_class ()
+   {
+      return ExtraInstruction.class;
+   }
+
+   public ExtraInstructionCompiler (final Compiler compiler)
+   {
+      super(compiler);
+   }
+
+   /*
+    * Fate: (event_call <string> c0 ... cn)
+    *
+    * Wyrd (event_call <string> c0 ... cn)
+    */
+   public void compile
+   (
+      final tonkadur.fate.v1.lang.instruction.GenericInstruction instruction
+   )
+   throws Throwable
+   {
+      final ExtraInstruction source;
+      final List<ComputationCompiler> cc_list;
+      final List<Computation> parameters;
+
+      source = (ExtraInstruction) instruction;
+
+      cc_list = new ArrayList<ComputationCompiler>();
+      parameters = new ArrayList<Computation>();
+
+      for
+      (
+         final tonkadur.fate.v1.lang.meta.Computation fate_computation:
+            source.get_parameters()
+      )
+      {
+         final ComputationCompiler cc;
+
+         cc = new ComputationCompiler(compiler);
+
+         fate_computation.get_visited_by(cc);
+
+         if (cc.has_init())
+         {
+            result.add(cc.get_init());
+         }
+
+         cc_list.add(cc);
+         parameters.add(cc.get_computation());
+      }
+
+      result.add
+      (
+         new tonkadur.wyrd.v1.lang.instruction.ExtraInstruction
+         (
+            source.get_instruction_name(),
+            parameters
+         )
+      );
+
+      for (final ComputationCompiler cc: cc_list)
+      {
+         cc.release_registers(result);
+      }
+   }
+}