...

23 files changed, 1219 insertions, 128 deletions

diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/FilterComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/FilterComputation.java
index 9fdb63f..821c231 100644
--- a/src/core/src/tonkadur/fate/v1/lang/computation/FilterComputation.java
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/FilterComputation.java
@@ -1,6 +1,8 @@
 package tonkadur.fate.v1.lang.computation;
 
 import java.util.Collections;
+import java.util.List;
+import java.util.ArrayList;
 
 import tonkadur.parser.Origin;
 import tonkadur.parser.ParsingError;
@@ -18,6 +20,7 @@ public class FilterComputation extends Computation
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
+   protected final List<Computation> extra_params;
    protected final Computation lambda_function;
    protected final Computation collection;
 
@@ -29,13 +32,15 @@ public class FilterComputation extends Computation
    (
       final Origin origin,
       final Computation lambda_function,
-      final Computation collection
+      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;
    }
 
    /***************************************************************************/
@@ -46,22 +51,42 @@ public class FilterComputation extends Computation
    (
       final Origin origin,
       final Computation lambda_function,
-      final Computation collection
+      final Computation collection,
+      final List<Computation> extra_params
    )
    throws ParsingError
    {
+      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,
-         Collections.singletonList
-         (
-            ((CollectionType) collection.get_type()).get_content_type()
-         )
+         target_signature
       );
 
-      return new FilterComputation(origin, lambda_function, collection);
+      return
+         new FilterComputation
+         (
+            origin,
+            lambda_function,
+            collection,
+            extra_params
+         );
    }
 
    /**** Accessors ************************************************************/
@@ -82,6 +107,11 @@ public class FilterComputation extends Computation
       return collection;
    }
 
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
    /**** Misc. ****************************************************************/
    @Override
    public String toString ()
@@ -92,6 +122,13 @@ public class FilterComputation extends Computation
       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/Fold.java b/src/core/src/tonkadur/fate/v1/lang/computation/Fold.java
index 2be97d1..1e9041b 100644
--- a/src/core/src/tonkadur/fate/v1/lang/computation/Fold.java
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/Fold.java
@@ -20,6 +20,7 @@ public class Fold extends Computation
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
+   protected final List<Computation> extra_params;
    protected final Computation lambda_function;
    protected final Computation initial_value;
    protected final Computation collection;
@@ -36,6 +37,7 @@ public class Fold extends Computation
       final Computation initial_value,
       final Computation collection,
       final boolean is_foldl,
+      final List<Computation> extra_params,
       final Type act_as
    )
    {
@@ -45,6 +47,7 @@ public class Fold extends Computation
       this.initial_value = initial_value;
       this.collection = collection;
       this.is_foldl = is_foldl;
+      this.extra_params = extra_params;
    }
 
    /***************************************************************************/
@@ -57,7 +60,8 @@ public class Fold extends Computation
       final Computation lambda_function,
       final Computation initial_value,
       final Computation collection,
-      final boolean is_foldl
+      final boolean is_foldl,
+      final List<Computation> extra_params
    )
    throws ParsingError
    {
@@ -73,6 +77,11 @@ public class Fold extends Computation
          ((CollectionType) collection.get_type()).get_content_type()
       );
 
+      for (final Computation c: extra_params)
+      {
+         types_in.add(c.get_type());
+      }
+
       RecurrentChecks.assert_lambda_matches_types
       (
          lambda_function,
@@ -88,6 +97,7 @@ public class Fold extends Computation
             initial_value,
             collection,
             is_foldl,
+            extra_params,
             initial_value.get_type()
          );
    }
@@ -120,6 +130,11 @@ public class Fold extends Computation
       return is_foldl;
    }
 
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
    /**** Misc. ****************************************************************/
    @Override
    public String toString ()
@@ -141,6 +156,13 @@ public class Fold extends Computation
       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/IndexedMapComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/IndexedMapComputation.java
index 7190582..f85616a 100644
--- a/src/core/src/tonkadur/fate/v1/lang/computation/IndexedMapComputation.java
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/IndexedMapComputation.java
@@ -20,6 +20,7 @@ public class IndexedMapComputation extends Computation
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
+   protected final List<Computation> extra_params;
    protected final Computation lambda_function;
    protected final Computation collection;
 
@@ -32,6 +33,7 @@ public class IndexedMapComputation extends Computation
       final Origin origin,
       final Computation lambda_function,
       final Computation collection,
+      final List<Computation> extra_params,
       final Type output_type
    )
    {
@@ -39,6 +41,7 @@ public class IndexedMapComputation extends Computation
 
       this.lambda_function = lambda_function;
       this.collection = collection;
+      this.extra_params = extra_params;
    }
 
    /***************************************************************************/
@@ -49,7 +52,8 @@ public class IndexedMapComputation extends Computation
    (
       final Origin origin,
       final Computation lambda_function,
-      final Computation collection
+      final Computation collection,
+      final List<Computation> extra_params
    )
    throws Throwable
    {
@@ -65,6 +69,11 @@ public class IndexedMapComputation extends Computation
          ((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
@@ -73,6 +82,7 @@ public class IndexedMapComputation extends Computation
             origin,
             lambda_function,
             collection,
+            extra_params,
             CollectionType.build
             (
                origin,
@@ -101,6 +111,11 @@ public class IndexedMapComputation extends Computation
       return collection;
    }
 
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
    /**** Misc. ****************************************************************/
    @Override
    public String toString ()
@@ -111,6 +126,13 @@ public class IndexedMapComputation extends Computation
       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/MapComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/MapComputation.java
index 394dd9a..86bd6e4 100644
--- a/src/core/src/tonkadur/fate/v1/lang/computation/MapComputation.java
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/MapComputation.java
@@ -1,6 +1,8 @@
 package tonkadur.fate.v1.lang.computation;
 
 import java.util.Collections;
+import java.util.List;
+import java.util.ArrayList;
 
 import tonkadur.parser.Origin;
 import tonkadur.parser.ParsingError;
@@ -19,6 +21,7 @@ public class MapComputation extends Computation
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
+   protected final List<Computation> extra_params;
    protected final Computation lambda_function;
    protected final Computation collection;
 
@@ -31,12 +34,15 @@ public class MapComputation extends Computation
       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;
    }
 
    /***************************************************************************/
@@ -47,18 +53,31 @@ public class MapComputation extends Computation
    (
       final Origin origin,
       final Computation lambda_function,
-      final Computation collection
+      final Computation collection,
+      final List<Computation> extra_params
    )
    throws ParsingError
    {
+      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,
-         Collections.singletonList
-         (
-            ((CollectionType) collection.get_type()).get_content_type()
-         )
+         target_signature
       );
 
       return
@@ -67,6 +86,7 @@ public class MapComputation extends Computation
             origin,
             lambda_function,
             collection,
+            extra_params,
             CollectionType.build
             (
                origin,
@@ -95,6 +115,11 @@ public class MapComputation extends Computation
       return collection;
    }
 
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
    /**** Misc. ****************************************************************/
    @Override
    public String toString ()
@@ -105,6 +130,13 @@ public class MapComputation extends Computation
       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/MergeComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/MergeComputation.java
index e961729..4df3d3b 100644
--- a/src/core/src/tonkadur/fate/v1/lang/computation/MergeComputation.java
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/MergeComputation.java
@@ -22,6 +22,7 @@ public class MergeComputation extends Computation
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
+   protected final List<Computation> extra_params;
    protected final Computation lambda_function;
    protected final Computation collection_in_a;
    protected final Computation default_a;
@@ -42,6 +43,7 @@ public class MergeComputation extends Computation
       final Computation collection_in_b,
       final Computation default_b,
       final boolean to_set,
+      final List<Computation> extra_params,
       final Type output_type
    )
    {
@@ -53,6 +55,7 @@ public class MergeComputation extends Computation
       this.collection_in_b = collection_in_b;
       this.default_b = default_b;
       this.to_set = to_set;
+      this.extra_params = extra_params;
    }
 
    /***************************************************************************/
@@ -67,7 +70,8 @@ public class MergeComputation extends Computation
       final Computation default_a,
       final Computation collection_in_b,
       final Computation default_b,
-      final boolean to_set
+      final boolean to_set,
+      final List<Computation> extra_params
    )
    throws Throwable
    {
@@ -103,6 +107,11 @@ public class MergeComputation extends Computation
          ((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
@@ -115,6 +124,7 @@ public class MergeComputation extends Computation
             collection_in_b,
             default_b,
             to_set,
+            extra_params,
             CollectionType.build
             (
                origin,
@@ -158,6 +168,11 @@ public class MergeComputation extends Computation
       return default_b;
    }
 
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
    public boolean to_set ()
    {
       return to_set;
@@ -205,6 +220,12 @@ public class MergeComputation extends Computation
          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/PartitionComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/PartitionComputation.java
index 75bc3d6..b240915 100644
--- a/src/core/src/tonkadur/fate/v1/lang/computation/PartitionComputation.java
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/PartitionComputation.java
@@ -1,6 +1,8 @@
 package tonkadur.fate.v1.lang.computation;
 
 import java.util.Collections;
+import java.util.List;
+import java.util.ArrayList;
 
 import tonkadur.parser.Origin;
 import tonkadur.parser.ParsingError;
@@ -19,6 +21,7 @@ public class PartitionComputation extends Computation
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
+   protected final List<Computation> extra_params;
    protected final Computation lambda_function;
    protected final Computation collection;
 
@@ -31,6 +34,7 @@ public class PartitionComputation extends Computation
       final Origin origin,
       final Computation lambda_function,
       final Computation collection,
+      final List<Computation> extra_params,
       final Type output_type
    )
    {
@@ -38,6 +42,7 @@ public class PartitionComputation extends Computation
 
       this.lambda_function = lambda_function;
       this.collection = collection;
+      this.extra_params = extra_params;
    }
 
    /***************************************************************************/
@@ -48,22 +53,33 @@ public class PartitionComputation extends Computation
    (
       final Origin origin,
       final Computation lambda_function,
-      final Computation collection
+      final Computation collection,
+      final List<Computation> extra_params
    )
    throws Throwable
    {
       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,
-         Collections.singletonList
-         (
-            ((CollectionType) collection.get_type()).get_content_type()
-         )
+         target_signature
       );
 
       type =
@@ -81,6 +97,7 @@ public class PartitionComputation extends Computation
             origin,
             lambda_function,
             collection,
+            extra_params,
             type
          );
    }
@@ -103,6 +120,11 @@ public class PartitionComputation extends Computation
       return collection;
    }
 
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
    /**** Misc. ****************************************************************/
    @Override
    public String toString ()
@@ -113,6 +135,13 @@ public class PartitionComputation extends Computation
       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/SortComputation.java b/src/core/src/tonkadur/fate/v1/lang/computation/SortComputation.java
index 7127920..ebb9279 100644
--- a/src/core/src/tonkadur/fate/v1/lang/computation/SortComputation.java
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/SortComputation.java
@@ -21,6 +21,7 @@ public class SortComputation extends Computation
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
+   protected final List<Computation> extra_params;
    protected final Computation lambda_function;
    protected final Computation collection;
 
@@ -32,13 +33,15 @@ public class SortComputation extends Computation
    (
       final Origin origin,
       final Computation lambda_function,
-      final Computation collection
+      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;
    }
 
    /***************************************************************************/
@@ -49,7 +52,8 @@ public class SortComputation extends Computation
    (
       final Origin origin,
       final Computation lambda_function,
-      final Computation collection
+      final Computation collection,
+      final List<Computation> extra_params
    )
    throws ParsingError
    {
@@ -62,6 +66,11 @@ public class SortComputation extends Computation
       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,
@@ -69,7 +78,8 @@ public class SortComputation extends Computation
          types_in
       );
 
-      return new SortComputation(origin, lambda_function, collection);
+      return
+         new SortComputation(origin, lambda_function, collection, extra_params);
    }
 
    /**** Accessors ************************************************************/
@@ -90,6 +100,11 @@ public class SortComputation extends Computation
       return collection;
    }
 
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
    /**** Misc. ****************************************************************/
    @Override
    public String toString ()
@@ -100,6 +115,13 @@ public class SortComputation extends Computation
       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/instruction/Filter.java b/src/core/src/tonkadur/fate/v1/lang/instruction/Filter.java
index d81997c..d91f297 100644
--- a/src/core/src/tonkadur/fate/v1/lang/instruction/Filter.java
+++ b/src/core/src/tonkadur/fate/v1/lang/instruction/Filter.java
@@ -2,6 +2,7 @@ package tonkadur.fate.v1.lang.instruction;
 
 import java.util.Collections;
 import java.util.List;
+import java.util.ArrayList;
 
 import tonkadur.parser.Origin;
 import tonkadur.parser.ParsingError;
@@ -21,6 +22,7 @@ public class Filter extends Instruction
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
+   protected final List<Computation> extra_params;
    protected final Computation lambda_function;
    protected final Reference collection;
 
@@ -32,13 +34,15 @@ public class Filter extends Instruction
    (
       final Origin origin,
       final Computation lambda_function,
-      final Reference collection
+      final Reference collection,
+      final List<Computation> extra_params
    )
    {
       super(origin);
 
       this.lambda_function = lambda_function;
       this.collection = collection;
+      this.extra_params = extra_params;
    }
 
    /***************************************************************************/
@@ -49,23 +53,34 @@ public class Filter extends Instruction
    (
       final Origin origin,
       final Computation lambda_function,
-      final Reference collection
+      final Reference collection,
+      final List<Computation> extra_params
    )
    throws ParsingError
    {
+      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,
-         Collections.singletonList
-         (
-            ((CollectionType) collection.get_type()).get_content_type()
-         )
+         target_signature
       );
 
-      return new Filter(origin, lambda_function, collection);
+      return new Filter(origin, lambda_function, collection, extra_params);
    }
 
    /**** Accessors ************************************************************/
@@ -86,6 +101,11 @@ public class Filter extends Instruction
       return collection;
    }
 
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
    /**** Misc. ****************************************************************/
    @Override
    public String toString ()
@@ -96,6 +116,13 @@ public class Filter extends Instruction
       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/instruction/IfInstruction.java b/src/core/src/tonkadur/fate/v1/lang/instruction/IfInstruction.java
index a8751d1..0f29115 100644
--- a/src/core/src/tonkadur/fate/v1/lang/instruction/IfInstruction.java
+++ b/src/core/src/tonkadur/fate/v1/lang/instruction/IfInstruction.java
@@ -1,5 +1,7 @@
 package tonkadur.fate.v1.lang.instruction;
 
+import java.util.List;
+
 import tonkadur.parser.Origin;
 import tonkadur.parser.ParsingError;
 
@@ -16,7 +18,7 @@ public class IfInstruction extends Instruction
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
    protected final Computation condition;
-   protected final Instruction if_true;
+   protected final List<Instruction> if_true;
 
    /***************************************************************************/
    /**** PROTECTED ************************************************************/
@@ -26,7 +28,7 @@ public class IfInstruction extends Instruction
    (
       final Origin origin,
       final Computation condition,
-      final Instruction if_true
+      final List<Instruction> if_true
    )
    {
       super(origin);
@@ -43,7 +45,7 @@ public class IfInstruction extends Instruction
    (
       final Origin origin,
       final Computation condition,
-      final Instruction if_true
+      final List<Instruction> if_true
    )
    throws ParsingError
    {
@@ -65,7 +67,7 @@ public class IfInstruction extends Instruction
       return condition;
    }
 
-   public Instruction get_if_true ()
+   public List<Instruction> get_if_true ()
    {
       return if_true;
    }
@@ -79,8 +81,12 @@ public class IfInstruction extends Instruction
       sb.append("(IfInstruction");
       sb.append(System.lineSeparator());
       sb.append(condition.toString());
-      sb.append(System.lineSeparator());
-      sb.append(if_true.toString());
+
+      for (final Instruction instr: if_true)
+      {
+         sb.append(System.lineSeparator());
+         sb.append(instr.toString());
+      }
 
       sb.append(")");
 
diff --git a/src/core/src/tonkadur/fate/v1/lang/instruction/IndexedMap.java b/src/core/src/tonkadur/fate/v1/lang/instruction/IndexedMap.java
index 094561b..e603332 100644
--- a/src/core/src/tonkadur/fate/v1/lang/instruction/IndexedMap.java
+++ b/src/core/src/tonkadur/fate/v1/lang/instruction/IndexedMap.java
@@ -20,6 +20,7 @@ public class IndexedMap extends Instruction
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
+   protected final List<Computation> extra_params;
    protected final Computation lambda_function;
    protected final Reference collection;
 
@@ -31,13 +32,15 @@ public class IndexedMap extends Instruction
    (
       final Origin origin,
       final Computation lambda_function,
-      final Reference collection
+      final Reference collection,
+      final List<Computation> extra_params
    )
    {
       super(origin);
 
       this.lambda_function = lambda_function;
       this.collection = collection;
+      this.extra_params = extra_params;
    }
 
    /***************************************************************************/
@@ -48,7 +51,8 @@ public class IndexedMap extends Instruction
    (
       final Origin origin,
       final Computation lambda_function,
-      final Reference collection
+      final Reference collection,
+      final List<Computation> extra_params
    )
    throws Throwable
    {
@@ -64,6 +68,11 @@ public class IndexedMap extends Instruction
          ((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,
@@ -71,7 +80,7 @@ public class IndexedMap extends Instruction
          in_types
       );
 
-      return new IndexedMap(origin, lambda_function, collection);
+      return new IndexedMap(origin, lambda_function, collection, extra_params);
    }
 
    /**** Accessors ************************************************************/
@@ -92,6 +101,11 @@ public class IndexedMap extends Instruction
       return collection;
    }
 
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
    /**** Misc. ****************************************************************/
    @Override
    public String toString ()
@@ -102,6 +116,13 @@ public class IndexedMap extends Instruction
       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/instruction/Map.java b/src/core/src/tonkadur/fate/v1/lang/instruction/Map.java
index 0cc941f..1bcb1e4 100644
--- a/src/core/src/tonkadur/fate/v1/lang/instruction/Map.java
+++ b/src/core/src/tonkadur/fate/v1/lang/instruction/Map.java
@@ -2,6 +2,7 @@ package tonkadur.fate.v1.lang.instruction;
 
 import java.util.Collections;
 import java.util.List;
+import java.util.ArrayList;
 
 import tonkadur.parser.Origin;
 import tonkadur.parser.ParsingError;
@@ -20,6 +21,7 @@ public class Map extends Instruction
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
+   protected final List<Computation> extra_params;
    protected final Computation lambda_function;
    protected final Reference collection;
 
@@ -31,13 +33,15 @@ public class Map extends Instruction
    (
       final Origin origin,
       final Computation lambda_function,
-      final Reference collection
+      final Reference collection,
+      final List<Computation> extra_params
    )
    {
       super(origin);
 
       this.lambda_function = lambda_function;
       this.collection = collection;
+      this.extra_params = extra_params;
    }
 
    /***************************************************************************/
@@ -48,22 +52,35 @@ public class Map extends Instruction
    (
       final Origin origin,
       final Computation lambda_function,
-      final Reference collection
+      final Reference collection,
+      final List<Computation> extra_params
    )
    throws ParsingError
    {
+      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,
          ((CollectionType) collection.get_type()).get_content_type(),
-         Collections.singletonList
-         (
-            ((CollectionType) collection.get_type()).get_content_type()
-         )
+         target_signature
       );
 
-      return new Map(origin, lambda_function, collection);
+      return new Map(origin, lambda_function, collection, extra_params);
    }
 
    /**** Accessors ************************************************************/
@@ -84,6 +101,11 @@ public class Map extends Instruction
       return collection;
    }
 
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
    /**** Misc. ****************************************************************/
    @Override
    public String toString ()
@@ -94,6 +116,13 @@ public class Map extends Instruction
       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/instruction/Merge.java b/src/core/src/tonkadur/fate/v1/lang/instruction/Merge.java
index b5821ed..f2396a9 100644
--- a/src/core/src/tonkadur/fate/v1/lang/instruction/Merge.java
+++ b/src/core/src/tonkadur/fate/v1/lang/instruction/Merge.java
@@ -20,6 +20,7 @@ public class Merge extends Instruction
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
+   protected final List<Computation> extra_params;
    protected final Computation lambda_function;
    protected final Reference collection;
    protected final Computation default_a;
@@ -37,7 +38,8 @@ public class Merge extends Instruction
       final Reference collection,
       final Computation default_a,
       final Computation collection_in_b,
-      final Computation default_b
+      final Computation default_b,
+      final List<Computation> extra_params
    )
    {
       super(origin);
@@ -47,6 +49,7 @@ public class Merge extends Instruction
       this.default_a = default_a;
       this.collection_in_b = collection_in_b;
       this.default_b = default_b;
+      this.extra_params = extra_params;
    }
 
    /***************************************************************************/
@@ -60,7 +63,8 @@ public class Merge extends Instruction
       final Reference collection,
       final Computation default_a,
       final Computation collection_in_b,
-      final Computation default_b
+      final Computation default_b,
+      final List<Computation> extra_params
    )
    throws Throwable
    {
@@ -96,6 +100,11 @@ public class Merge extends Instruction
          ((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,
@@ -111,7 +120,8 @@ public class Merge extends Instruction
             collection,
             default_a,
             collection_in_b,
-            default_b
+            default_b,
+            extra_params
          );
    }
 
@@ -148,6 +158,11 @@ public class Merge extends Instruction
       return collection;
    }
 
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
    /**** Misc. ****************************************************************/
    @Override
    public String toString ()
@@ -182,6 +197,12 @@ public class Merge extends Instruction
          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/instruction/Partition.java b/src/core/src/tonkadur/fate/v1/lang/instruction/Partition.java
index c075c9b..33cb152 100644
--- a/src/core/src/tonkadur/fate/v1/lang/instruction/Partition.java
+++ b/src/core/src/tonkadur/fate/v1/lang/instruction/Partition.java
@@ -1,6 +1,8 @@
 package tonkadur.fate.v1.lang.instruction;
 
 import java.util.Collections;
+import java.util.List;
+import java.util.ArrayList;
 
 import tonkadur.parser.Origin;
 import tonkadur.parser.ParsingError;
@@ -19,6 +21,7 @@ public class Partition extends Instruction
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
+   protected final List<Computation> extra_params;
    protected final Computation lambda_function;
    protected final Reference collection_in;
    protected final Reference collection_out;
@@ -32,7 +35,8 @@ public class Partition extends Instruction
       final Origin origin,
       final Computation lambda_function,
       final Reference collection_in,
-      final Reference collection_out
+      final Reference collection_out,
+      final List<Computation> extra_params
    )
    {
       super(origin);
@@ -40,6 +44,7 @@ public class Partition extends Instruction
       this.lambda_function = lambda_function;
       this.collection_in = collection_in;
       this.collection_out = collection_out;
+      this.extra_params = extra_params;
    }
 
    /***************************************************************************/
@@ -51,10 +56,15 @@ public class Partition extends Instruction
       final Origin origin,
       final Computation lambda_function,
       final Reference collection_in,
-      final Reference collection_out
+      final Reference collection_out,
+      final List<Computation> extra_params
    )
    throws ParsingError
    {
+      final List<Type> target_signature;
+
+      target_signature = new ArrayList<Type>();
+
       RecurrentChecks.assert_is_a_collection(collection_in);
       RecurrentChecks.assert_is_a_collection(collection_out);
       RecurrentChecks.assert_can_be_used_as
@@ -63,14 +73,21 @@ public class Partition extends Instruction
          collection_out.get_type()
       );
 
+      target_signature.add
+      (
+         ((CollectionType) collection_in.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,
-         Collections.singletonList
-         (
-            ((CollectionType) collection_in.get_type()).get_content_type()
-         )
+         target_signature
       );
 
       return
@@ -79,7 +96,8 @@ public class Partition extends Instruction
             origin,
             lambda_function,
             collection_in,
-            collection_out
+            collection_out,
+            extra_params
          );
    }
 
@@ -106,6 +124,11 @@ public class Partition extends Instruction
       return collection_out;
    }
 
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
    /**** Misc. ****************************************************************/
    @Override
    public String toString ()
@@ -118,6 +141,13 @@ public class Partition extends Instruction
       sb.append(collection_in.toString());
       sb.append(" ");
       sb.append(collection_out.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/instruction/Sort.java b/src/core/src/tonkadur/fate/v1/lang/instruction/Sort.java
index 083b1a1..f19a4fc 100644
--- a/src/core/src/tonkadur/fate/v1/lang/instruction/Sort.java
+++ b/src/core/src/tonkadur/fate/v1/lang/instruction/Sort.java
@@ -20,6 +20,7 @@ public class Sort extends Instruction
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
+   protected final List<Computation> extra_params;
    protected final Computation lambda_function;
    protected final Reference collection;
 
@@ -31,13 +32,15 @@ public class Sort extends Instruction
    (
       final Origin origin,
       final Computation lambda_function,
-      final Reference collection
+      final Reference collection,
+      final List<Computation> extra_params
    )
    {
       super(origin);
 
       this.lambda_function = lambda_function;
       this.collection = collection;
+      this.extra_params = extra_params;
    }
 
    /***************************************************************************/
@@ -48,7 +51,8 @@ public class Sort extends Instruction
    (
       final Origin origin,
       final Computation lambda_function,
-      final Reference collection
+      final Reference collection,
+      final List<Computation> extra_params
    )
    throws Throwable
    {
@@ -61,6 +65,11 @@ public class Sort extends Instruction
       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,
@@ -68,7 +77,7 @@ public class Sort extends Instruction
          types_in
       );
 
-      return new Sort(origin, lambda_function, collection);
+      return new Sort(origin, lambda_function, collection, extra_params);
    }
 
    /**** Accessors ************************************************************/
@@ -89,6 +98,11 @@ public class Sort extends Instruction
       return collection;
    }
 
+   public List<Computation> get_extra_parameters ()
+   {
+      return extra_params;
+   }
+
    /**** Misc. ****************************************************************/
    @Override
    public String toString ()
@@ -99,6 +113,13 @@ public class Sort extends Instruction
       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/meta/VariableFromWord.java b/src/core/src/tonkadur/fate/v1/lang/meta/VariableFromWord.java
new file mode 100644
index 0000000..554ae86
--- /dev/null
+++ b/src/core/src/tonkadur/fate/v1/lang/meta/VariableFromWord.java
@@ -0,0 +1,66 @@
+package tonkadur.fate.v1.lang.meta;
+
+import java.util.Map;
+import java.util.Deque;
+import java.util.Arrays;
+import java.util.List;
+import java.util.ArrayList;
+
+import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
+
+import tonkadur.fate.v1.lang.computation.VariableReference;
+import tonkadur.fate.v1.lang.computation.FieldReference;
+
+import tonkadur.fate.v1.lang.Variable;
+import tonkadur.fate.v1.lang.World;
+
+public class VariableFromWord
+{
+   /* Utility Class */
+   private VariableFromWord () { }
+
+   public static Reference generate
+   (
+      final World WORLD,
+      final Deque<Map<String, Variable>> LOCAL_VARIABLES,
+      final Origin origin,
+      final String word
+   )
+   throws ParsingError
+   {
+      final String[] subrefs;
+      Reference result;
+      Variable target_var;
+
+      subrefs = word.split("\\.");
+
+      target_var = LOCAL_VARIABLES.peekFirst().get(subrefs[0]);
+
+      if (target_var == null)
+      {
+         target_var = WORLD.variables().get(origin, subrefs[0]);
+      }
+
+      result = new VariableReference(origin, target_var);
+
+      if (subrefs.length > 1)
+      {
+         final List<String> subrefs_list;
+
+         subrefs_list = new ArrayList(Arrays.asList(subrefs));
+
+         subrefs_list.remove(0);
+
+         result =
+            FieldReference.build
+            (
+               origin,
+               result,
+               subrefs_list
+            );
+      }
+
+      return result;
+   }
+}
diff --git a/src/core/src/tonkadur/fate/v1/parser/FateParser.g4 b/src/core/src/tonkadur/fate/v1/parser/FateParser.g4
index 9f716b6..f4a3d12 100644
--- a/src/core/src/tonkadur/fate/v1/parser/FateParser.g4
+++ b/src/core/src/tonkadur/fate/v1/parser/FateParser.g4
@@ -820,7 +820,24 @@ returns [Instruction result]
                ($IMP_MAP_KW.getCharPositionInLine())
             ),
             ($non_text_value.result),
-            ($value_reference.result)
+            ($value_reference.result),
+            new ArrayList()
+         );
+   }
+
+   | IMP_MAP_KW non_text_value WS+ value_reference WS+ value_list WS* R_PAREN
+   {
+      $result =
+         tonkadur.fate.v1.lang.instruction.Map.build
+         (
+            CONTEXT.get_origin_at
+            (
+               ($IMP_MAP_KW.getLine()),
+               ($IMP_MAP_KW.getCharPositionInLine())
+            ),
+            ($non_text_value.result),
+            ($value_reference.result),
+            ($value_list.result)
          );
    }
 
@@ -835,7 +852,28 @@ returns [Instruction result]
                ($IMP_INDEXED_MAP_KW.getCharPositionInLine())
             ),
             ($non_text_value.result),
-            ($value_reference.result)
+            ($value_reference.result),
+            new ArrayList()
+         );
+   }
+
+   | IMP_INDEXED_MAP_KW
+         non_text_value WS+
+         value_reference WS+
+         value_list WS*
+      R_PAREN
+   {
+      $result =
+         IndexedMap.build
+         (
+            CONTEXT.get_origin_at
+            (
+               ($IMP_INDEXED_MAP_KW.getLine()),
+               ($IMP_INDEXED_MAP_KW.getCharPositionInLine())
+            ),
+            ($non_text_value.result),
+            ($value_reference.result),
+            ($value_list.result)
          );
    }
 
@@ -857,7 +895,32 @@ returns [Instruction result]
             ($value_reference.result),
             null,
             ($inv1.result),
-            null
+            null,
+            new ArrayList()
+         );
+   }
+
+   | IMP_MERGE_KW
+         fun=non_text_value WS+
+         value_reference WS+
+         inv1=non_text_value WS+
+         value_list WS*
+      R_PAREN
+   {
+      $result =
+         Merge.build
+         (
+            CONTEXT.get_origin_at
+            (
+               ($IMP_MERGE_KW.getLine()),
+               ($IMP_MERGE_KW.getCharPositionInLine())
+            ),
+            ($fun.result),
+            ($value_reference.result),
+            null,
+            ($inv1.result),
+            null,
+            ($value_list.result)
          );
    }
 
@@ -881,7 +944,34 @@ returns [Instruction result]
             ($value_reference.result),
             ($def0.result),
             ($inv1.result),
-            ($def1.result)
+            ($def1.result),
+            new ArrayList()
+         );
+   }
+
+   | IMP_MERGE_KW
+      fun=non_text_value WS+
+      def0=value WS+
+      value_reference WS+
+      def1=value WS+
+      inv1=non_text_value WS+
+      value_list WS*
+      R_PAREN
+   {
+      $result =
+         Merge.build
+         (
+            CONTEXT.get_origin_at
+            (
+               ($IMP_MERGE_KW.getLine()),
+               ($IMP_MERGE_KW.getCharPositionInLine())
+            ),
+            ($fun.result),
+            ($value_reference.result),
+            ($def0.result),
+            ($inv1.result),
+            ($def1.result),
+            ($value_list.result)
          );
    }
 
@@ -916,7 +1006,24 @@ returns [Instruction result]
                ($IMP_FILTER_KW.getCharPositionInLine())
             ),
             ($non_text_value.result),
-            ($value_reference.result)
+            ($value_reference.result),
+            new ArrayList()
+         );
+   }
+
+   | IMP_FILTER_KW non_text_value WS+ value_reference WS+ value_list WS* R_PAREN
+   {
+      $result =
+         Filter.build
+         (
+            CONTEXT.get_origin_at
+            (
+               ($IMP_FILTER_KW.getLine()),
+               ($IMP_FILTER_KW.getCharPositionInLine())
+            ),
+            ($non_text_value.result),
+            ($value_reference.result),
+            ($value_list.result)
          );
    }
 
@@ -936,7 +1043,30 @@ returns [Instruction result]
             ),
             ($non_text_value.result),
             ($iftrue.result),
-            ($iffalse.result)
+            ($iffalse.result),
+            new ArrayList()
+         );
+   }
+
+   | IMP_PARTITION_KW
+      non_text_value WS+
+      iftrue=value_reference WS+
+      iffalse=value_reference WS+
+      value_list WS*
+      R_PAREN
+   {
+      $result =
+        Partition.build
+         (
+            CONTEXT.get_origin_at
+            (
+               ($IMP_PARTITION_KW.getLine()),
+               ($IMP_PARTITION_KW.getCharPositionInLine())
+            ),
+            ($non_text_value.result),
+            ($iftrue.result),
+            ($iffalse.result),
+            ($value_list.result)
          );
    }
 
@@ -951,7 +1081,24 @@ returns [Instruction result]
                ($IMP_SORT_KW.getCharPositionInLine())
             ),
             ($non_text_value.result),
-            ($value_reference.result)
+            ($value_reference.result),
+            new ArrayList()
+         );
+   }
+
+   | IMP_SORT_KW non_text_value WS+ value_reference WS+ value_list WS* R_PAREN
+   {
+      $result =
+        Sort.build
+         (
+            CONTEXT.get_origin_at
+            (
+               ($IMP_SORT_KW.getLine()),
+               ($IMP_SORT_KW.getCharPositionInLine())
+            ),
+            ($non_text_value.result),
+            ($value_reference.result),
+            ($value_list.result)
          );
    }
 
@@ -1397,7 +1544,7 @@ returns [Instruction result]
       {
          HIERARCHICAL_VARIABLES.push(new ArrayList());
       }
-      general_fate_instr
+      general_fate_sequence
       {
          for (final String s: HIERARCHICAL_VARIABLES.pop())
          {
@@ -1415,7 +1562,7 @@ returns [Instruction result]
                ($IF_KW.getCharPositionInLine())
             ),
             ($non_text_value.result),
-            ($general_fate_instr.result)
+            ($general_fate_sequence.result)
          );
    }
 
@@ -1713,7 +1860,10 @@ returns [Instruction result]
          );
    }
 
-   | IF_KW non_text_value WS+ player_choice WS* R_PAREN
+   | IF_KW
+         non_text_value WS+
+         player_choice_list WS*
+      R_PAREN
    {
       $result =
          IfInstruction.build
@@ -1724,7 +1874,7 @@ returns [Instruction result]
                ($IF_KW.getCharPositionInLine())
             ),
             ($non_text_value.result),
-            ($player_choice.result)
+            ($player_choice_list.result)
          );
    }
 
@@ -3259,7 +3409,31 @@ returns [Computation result]
             ($fun.result),
             ($init.result),
             ($inr.result),
-            true
+            true,
+            new ArrayList()
+         );
+   }
+
+   | FOLDL_KW
+         fun=non_text_value WS+
+         init=value WS+
+         inr=value_reference WS+
+         value_list WS*
+      R_PAREN
+   {
+      $result =
+         Fold.build
+         (
+            CONTEXT.get_origin_at
+            (
+               ($FOLDL_KW.getLine()),
+               ($FOLDL_KW.getCharPositionInLine())
+            ),
+            ($fun.result),
+            ($init.result),
+            ($inr.result),
+            true,
+            ($value_list.result)
          );
    }
 
@@ -3280,7 +3454,31 @@ returns [Computation result]
             ($fun.result),
             ($init.result),
             ($inr.result),
-            false
+            false,
+            new ArrayList()
+         );
+   }
+
+   | FOLDR_KW
+         fun=non_text_value WS+
+         init=value WS+
+         inr=value_reference WS+
+         value_list WS*
+      R_PAREN
+   {
+      $result =
+         Fold.build
+         (
+            CONTEXT.get_origin_at
+            (
+               ($FOLDR_KW.getLine()),
+               ($FOLDR_KW.getCharPositionInLine())
+            ),
+            ($fun.result),
+            ($init.result),
+            ($inr.result),
+            false,
+            ($value_list.result)
          );
    }
 
@@ -3723,7 +3921,24 @@ returns [Computation result]
                ($MAP_KW.getCharPositionInLine())
             ),
             ($fun.result),
-            ($inv.result)
+            ($inv.result),
+            new ArrayList()
+         );
+   }
+
+   | MAP_KW fun=non_text_value WS+ inv=non_text_value WS+ value_list WS* R_PAREN
+   {
+      $result =
+         tonkadur.fate.v1.lang.computation.MapComputation.build
+         (
+            CONTEXT.get_origin_at
+            (
+               ($MAP_KW.getLine()),
+               ($MAP_KW.getCharPositionInLine())
+            ),
+            ($fun.result),
+            ($inv.result),
+            ($value_list.result)
          );
    }
 
@@ -3738,7 +3953,28 @@ returns [Computation result]
                ($INDEXED_MAP_KW.getCharPositionInLine())
             ),
             ($fun.result),
-            ($inv.result)
+            ($inv.result),
+            new ArrayList()
+         );
+   }
+
+   | INDEXED_MAP_KW
+         fun=non_text_value WS+
+         inv=non_text_value WS+
+         value_list WS*
+      R_PAREN
+   {
+      $result =
+         IndexedMapComputation.build
+         (
+            CONTEXT.get_origin_at
+            (
+               ($INDEXED_MAP_KW.getLine()),
+               ($INDEXED_MAP_KW.getCharPositionInLine())
+            ),
+            ($fun.result),
+            ($inv.result),
+            ($value_list.result)
          );
    }
 
@@ -3761,7 +3997,33 @@ returns [Computation result]
             null,
             ($inv1.result),
             null,
-            false
+            false,
+            new ArrayList()
+         );
+   }
+
+   | MERGE_TO_LIST_KW
+         fun=non_text_value WS+
+         inv0=non_text_value WS+
+         inv1=non_text_value WS+
+         value_list WS*
+      R_PAREN
+   {
+      $result =
+         MergeComputation.build
+         (
+            CONTEXT.get_origin_at
+            (
+               ($MERGE_TO_LIST_KW.getLine()),
+               ($MERGE_TO_LIST_KW.getCharPositionInLine())
+            ),
+            ($fun.result),
+            ($inv0.result),
+            null,
+            ($inv1.result),
+            null,
+            false,
+            ($value_list.result)
          );
    }
 
@@ -3786,7 +4048,35 @@ returns [Computation result]
             ($def0.result),
             ($inv1.result),
             ($def1.result),
-            false
+            false,
+            new ArrayList()
+         );
+   }
+
+   | MERGE_TO_LIST_KW
+         fun=non_text_value WS+
+         def0=value WS+
+         inv0=non_text_value WS+
+         def1=value WS+
+         inv1=non_text_value WS+
+         value_list WS*
+      R_PAREN
+   {
+      $result =
+         MergeComputation.build
+         (
+            CONTEXT.get_origin_at
+            (
+               ($MERGE_TO_LIST_KW.getLine()),
+               ($MERGE_TO_LIST_KW.getCharPositionInLine())
+            ),
+            ($fun.result),
+            ($inv0.result),
+            ($def0.result),
+            ($inv1.result),
+            ($def1.result),
+            false,
+            ($value_list.result)
          );
    }
 
@@ -3809,7 +4099,33 @@ returns [Computation result]
             null,
             ($inv1.result),
             null,
-            true
+            true,
+            new ArrayList()
+         );
+   }
+
+   | MERGE_TO_SET_KW
+         fun=non_text_value WS+
+         inv0=non_text_value WS+
+         inv1=non_text_value WS+
+         value_list WS*
+      R_PAREN
+   {
+      $result =
+         MergeComputation.build
+         (
+            CONTEXT.get_origin_at
+            (
+               ($MERGE_TO_SET_KW.getLine()),
+               ($MERGE_TO_SET_KW.getCharPositionInLine())
+            ),
+            ($fun.result),
+            ($inv0.result),
+            null,
+            ($inv1.result),
+            null,
+            true,
+            ($value_list.result)
          );
    }
 
@@ -3834,7 +4150,35 @@ returns [Computation result]
             ($def0.result),
             ($inv1.result),
             ($def1.result),
-            true
+            true,
+            new ArrayList()
+         );
+   }
+
+   | MERGE_TO_SET_KW
+         fun=non_text_value WS+
+         def0=value WS+
+         inv0=non_text_value WS+
+         def1=value WS+
+         inv1=non_text_value WS+
+         value_list WS*
+      R_PAREN
+   {
+      $result =
+         MergeComputation.build
+         (
+            CONTEXT.get_origin_at
+            (
+               ($MERGE_TO_SET_KW.getLine()),
+               ($MERGE_TO_SET_KW.getCharPositionInLine())
+            ),
+            ($fun.result),
+            ($inv0.result),
+            ($def0.result),
+            ($inv1.result),
+            ($def1.result),
+            true,
+            ($value_list.result)
          );
    }
 
@@ -3869,7 +4213,28 @@ returns [Computation result]
                ($FILTER_KW.getCharPositionInLine())
             ),
             ($fun.result),
-            ($coll.result)
+            ($coll.result),
+            new ArrayList()
+         );
+   }
+
+   | FILTER_KW
+         fun=non_text_value WS+
+         coll=non_text_value WS+
+         value_list WS*
+      R_PAREN
+   {
+      $result =
+         FilterComputation.build
+         (
+            CONTEXT.get_origin_at
+            (
+               ($FILTER_KW.getLine()),
+               ($FILTER_KW.getCharPositionInLine())
+            ),
+            ($fun.result),
+            ($coll.result),
+            ($value_list.result)
          );
    }
 
@@ -3884,7 +4249,28 @@ returns [Computation result]
                ($PARTITION_KW.getCharPositionInLine())
             ),
             ($fun.result),
-            ($coll.result)
+            ($coll.result),
+            new ArrayList()
+         );
+   }
+
+   | PARTITION_KW
+         fun=non_text_value WS+
+         coll=non_text_value WS+
+         value_list WS*
+      R_PAREN
+   {
+      $result =
+        PartitionComputation.build
+         (
+            CONTEXT.get_origin_at
+            (
+               ($PARTITION_KW.getLine()),
+               ($PARTITION_KW.getCharPositionInLine())
+            ),
+            ($fun.result),
+            ($coll.result),
+            ($value_list.result)
          );
    }
 
@@ -3899,7 +4285,28 @@ returns [Computation result]
                ($SORT_KW.getCharPositionInLine())
             ),
             ($fun.result),
-            ($coll.result)
+            ($coll.result),
+            new ArrayList()
+         );
+   }
+
+   | SORT_KW
+         fun=non_text_value WS+
+         coll=non_text_value WS+
+         value_list WS*
+      R_PAREN
+   {
+      $result =
+        SortComputation.build
+         (
+            CONTEXT.get_origin_at
+            (
+               ($SORT_KW.getLine()),
+               ($SORT_KW.getCharPositionInLine())
+            ),
+            ($fun.result),
+            ($coll.result),
+            ($value_list.result)
          );
    }
 
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 161acba..487554e 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
@@ -2219,6 +2219,7 @@ implements tonkadur.fate.v1.lang.meta.ComputationVisitor
    )
    throws Throwable
    {
+      final List<Computation> params;
       final ComputationCompiler lambda_cc, in_collection_cc, default_cc;
       final Register result;
 
@@ -2227,6 +2228,28 @@ implements tonkadur.fate.v1.lang.meta.ComputationVisitor
       result_as_address = result.get_address();
       result_as_computation = result.get_value();
 
+      params = new ArrayList<Computation>();
+
+      for
+      (
+         final tonkadur.fate.v1.lang.meta.Computation p:
+            n.get_extra_parameters()
+      )
+      {
+         final ComputationCompiler param_cc;
+
+         param_cc = new ComputationCompiler(compiler);
+
+         p.get_visited_by(param_cc);
+
+         /* Let's not re-compute the parameters on every iteration. */
+         param_cc.generate_address();
+
+         assimilate(param_cc);
+
+         params.add(param_cc.get_computation());
+      }
+
       default_cc = new ComputationCompiler(compiler);
 
       n.get_initial_value().get_visited_by(default_cc);
@@ -2264,7 +2287,8 @@ implements tonkadur.fate.v1.lang.meta.ComputationVisitor
             lambda_cc.get_computation(),
             result_as_address,
             in_collection_cc.get_address(),
-            n.is_foldl()
+            n.is_foldl(),
+            params
          )
       );
    }
@@ -2276,6 +2300,7 @@ implements tonkadur.fate.v1.lang.meta.ComputationVisitor
    )
    throws Throwable
    {
+      final List<Computation> params;
       final ComputationCompiler lambda_cc, in_collection_cc;
       final Register result;
 
@@ -2284,6 +2309,28 @@ implements tonkadur.fate.v1.lang.meta.ComputationVisitor
       result_as_address = result.get_address();
       result_as_computation = result.get_value();
 
+      params = new ArrayList<Computation>();
+
+      for
+      (
+         final tonkadur.fate.v1.lang.meta.Computation p:
+            n.get_extra_parameters()
+      )
+      {
+         final ComputationCompiler param_cc;
+
+         param_cc = new ComputationCompiler(compiler);
+
+         p.get_visited_by(param_cc);
+
+         /* Let's not re-compute the parameters on every iteration. */
+         param_cc.generate_address();
+
+         assimilate(param_cc);
+
+         params.add(param_cc.get_computation());
+      }
+
       lambda_cc = new ComputationCompiler(compiler);
 
       n.get_lambda_function().get_visited_by(lambda_cc);
@@ -2308,7 +2355,8 @@ implements tonkadur.fate.v1.lang.meta.ComputationVisitor
             (
                (tonkadur.fate.v1.lang.type.CollectionType)
                n.get_collection().get_type()
-            ).is_set()
+            ).is_set(),
+            params
          )
       );
    }
@@ -2673,6 +2721,7 @@ implements tonkadur.fate.v1.lang.meta.ComputationVisitor
    )
    throws Throwable
    {
+      final List<Computation> params;
       final ComputationCompiler lambda_cc;
       final ComputationCompiler in_collection_a_cc, in_collection_b_cc;
       final Register result;
@@ -2682,6 +2731,28 @@ implements tonkadur.fate.v1.lang.meta.ComputationVisitor
       result_as_address = result.get_address();
       result_as_computation = result.get_value();
 
+      params = new ArrayList<Computation>();
+
+      for
+      (
+         final tonkadur.fate.v1.lang.meta.Computation p:
+            n.get_extra_parameters()
+      )
+      {
+         final ComputationCompiler param_cc;
+
+         param_cc = new ComputationCompiler(compiler);
+
+         p.get_visited_by(param_cc);
+
+         /* Let's not re-compute the parameters on every iteration. */
+         param_cc.generate_address();
+
+         assimilate(param_cc);
+
+         params.add(param_cc.get_computation());
+      }
+
       lambda_cc = new ComputationCompiler(compiler);
 
       n.get_lambda_function().get_visited_by(lambda_cc);
@@ -2710,7 +2781,8 @@ implements tonkadur.fate.v1.lang.meta.ComputationVisitor
             in_collection_a_cc.get_address(),
             in_collection_b_cc.get_address(),
             result_as_address,
-            n.to_set()
+            n.to_set(),
+            params
          )
       );
    }
@@ -2752,6 +2824,7 @@ implements tonkadur.fate.v1.lang.meta.ComputationVisitor
    )
    throws Throwable
    {
+      final List<Computation> params;
       final ComputationCompiler lambda_cc, in_collection_cc;
       final Register result;
 
@@ -2760,6 +2833,28 @@ implements tonkadur.fate.v1.lang.meta.ComputationVisitor
       result_as_address = result.get_address();
       result_as_computation = result.get_value();
 
+      params = new ArrayList<Computation>();
+
+      for
+      (
+         final tonkadur.fate.v1.lang.meta.Computation p:
+            n.get_extra_parameters()
+      )
+      {
+         final ComputationCompiler param_cc;
+
+         param_cc = new ComputationCompiler(compiler);
+
+         p.get_visited_by(param_cc);
+
+         /* Let's not re-compute the parameters on every iteration. */
+         param_cc.generate_address();
+
+         assimilate(param_cc);
+
+         params.add(param_cc.get_computation());
+      }
+
       lambda_cc = new ComputationCompiler(compiler);
 
       n.get_lambda_function().get_visited_by(lambda_cc);
@@ -2784,7 +2879,8 @@ implements tonkadur.fate.v1.lang.meta.ComputationVisitor
             compiler.registers(),
             compiler.assembler(),
             lambda_cc.get_computation(),
-            result_as_address
+            result_as_address,
+            params
          )
       );
    }
@@ -2796,6 +2892,7 @@ implements tonkadur.fate.v1.lang.meta.ComputationVisitor
    )
    throws Throwable
    {
+      final List<Computation> params;
       final ComputationCompiler lambda_cc, in_collection_cc;
       final Register result;
 
@@ -2804,6 +2901,28 @@ implements tonkadur.fate.v1.lang.meta.ComputationVisitor
       result_as_address = result.get_address();
       result_as_computation = result.get_value();
 
+      params = new ArrayList<Computation>();
+
+      for
+      (
+         final tonkadur.fate.v1.lang.meta.Computation p:
+            n.get_extra_parameters()
+      )
+      {
+         final ComputationCompiler param_cc;
+
+         param_cc = new ComputationCompiler(compiler);
+
+         p.get_visited_by(param_cc);
+
+         /* Let's not re-compute the parameters on every iteration. */
+         param_cc.generate_address();
+
+         assimilate(param_cc);
+
+         params.add(param_cc.get_computation());
+      }
+
       lambda_cc = new ComputationCompiler(compiler);
 
       n.get_lambda_function().get_visited_by(lambda_cc);
@@ -2828,7 +2947,8 @@ implements tonkadur.fate.v1.lang.meta.ComputationVisitor
             (
                (tonkadur.fate.v1.lang.type.CollectionType)
                n.get_collection().get_type()
-            ).is_set()
+            ).is_set(),
+            params
          )
       );
    }
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 aeee56e..a0a5810 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
@@ -532,10 +532,40 @@ implements tonkadur.fate.v1.lang.meta.InstructionVisitor
    )
    throws Throwable
    {
+      final List<Computation> params;
+      final List<ComputationCompiler> param_cc_list;
       /* This is one dangerous operation to do in-place, so we don't. */
       final Register holder;
       final ComputationCompiler lambda_cc, collection_cc;
 
+      params = new ArrayList<Computation>();
+      param_cc_list = new ArrayList<ComputationCompiler>();
+
+      for
+      (
+         final tonkadur.fate.v1.lang.meta.Computation p:
+            n.get_extra_parameters()
+      )
+      {
+         final ComputationCompiler param_cc;
+
+         param_cc = new ComputationCompiler(compiler);
+
+         p.get_visited_by(param_cc);
+
+         /* Let's not re-compute the parameters on every iteration. */
+         param_cc.generate_address();
+
+         if (param_cc.has_init())
+         {
+            result.add(param_cc.get_init());
+         }
+
+         param_cc_list.add(param_cc);
+
+         params.add(param_cc.get_computation());
+      }
+
       lambda_cc = new ComputationCompiler(compiler);
 
       n.get_lambda_function().get_visited_by(lambda_cc);
@@ -578,13 +608,19 @@ implements tonkadur.fate.v1.lang.meta.InstructionVisitor
             (
                (tonkadur.fate.v1.lang.type.CollectionType)
                n.get_collection().get_type()
-            ).is_set()
+            ).is_set(),
+            params
          )
       );
 
       lambda_cc.release_registers(result);
       collection_cc.release_registers(result);
       compiler.registers().release(holder, result);
+
+      for (final ComputationCompiler cc: param_cc_list)
+      {
+         cc.release_registers(result);
+      }
    }
 
    @Override
@@ -607,8 +643,13 @@ implements tonkadur.fate.v1.lang.meta.InstructionVisitor
       /* This is one dangerous operation to do in-place, so we don't. */
       final Register holder;
       final ComputationCompiler lambda_cc;
+      final List<Computation> params;
+      final List<ComputationCompiler> param_cc_list;
       final ComputationCompiler collection_cc, in_collection_b_cc;
 
+      params = new ArrayList<Computation>();
+      param_cc_list = new ArrayList<ComputationCompiler>();
+
       lambda_cc = new ComputationCompiler(compiler);
 
       n.get_lambda_function().get_visited_by(lambda_cc);
@@ -648,6 +689,31 @@ implements tonkadur.fate.v1.lang.meta.InstructionVisitor
          result.add(in_collection_b_cc.get_init());
       }
 
+      for
+      (
+         final tonkadur.fate.v1.lang.meta.Computation p:
+            n.get_extra_parameters()
+      )
+      {
+         final ComputationCompiler param_cc;
+
+         param_cc = new ComputationCompiler(compiler);
+
+         p.get_visited_by(param_cc);
+
+         /* Let's not re-compute the parameters on every iteration. */
+         param_cc.generate_address();
+
+         if (param_cc.has_init())
+         {
+            result.add(param_cc.get_init());
+         }
+
+         param_cc_list.add(param_cc);
+
+         params.add(param_cc.get_computation());
+      }
+
       result.add
       (
          MergeLambda.generate
@@ -661,13 +727,19 @@ implements tonkadur.fate.v1.lang.meta.InstructionVisitor
             (
                (tonkadur.fate.v1.lang.type.CollectionType)
                n.get_collection().get_type()
-            ).is_set()
+            ).is_set(),
+            params
          )
       );
 
       collection_cc.release_registers(result);
       in_collection_b_cc.release_registers(result);
       compiler.registers().release(holder, result);
+
+      for (final ComputationCompiler cc: param_cc_list)
+      {
+         cc.release_registers(result);
+      }
    }
 
    @Override
@@ -717,8 +789,38 @@ implements tonkadur.fate.v1.lang.meta.InstructionVisitor
    )
    throws Throwable
    {
+      final List<Computation> params;
+      final List<ComputationCompiler> param_cc_list;
       final ComputationCompiler lambda_cc, collection_cc;
 
+      params = new ArrayList<Computation>();
+      param_cc_list = new ArrayList<ComputationCompiler>();
+
+      for
+      (
+         final tonkadur.fate.v1.lang.meta.Computation p:
+            n.get_extra_parameters()
+      )
+      {
+         final ComputationCompiler param_cc;
+
+         param_cc = new ComputationCompiler(compiler);
+
+         p.get_visited_by(param_cc);
+
+         /* Let's not re-compute the parameters on every iteration. */
+         param_cc.generate_address();
+
+         if (param_cc.has_init())
+         {
+            result.add(param_cc.get_init());
+         }
+
+         param_cc_list.add(param_cc);
+
+         params.add(param_cc.get_computation());
+      }
+
       lambda_cc = new ComputationCompiler(compiler);
 
       n.get_lambda_function().get_visited_by(lambda_cc);
@@ -744,12 +846,18 @@ implements tonkadur.fate.v1.lang.meta.InstructionVisitor
             compiler.registers(),
             compiler.assembler(),
             lambda_cc.get_computation(),
-            collection_cc.get_address()
+            collection_cc.get_address(),
+            params
          )
       );
 
       lambda_cc.release_registers(result);
       collection_cc.release_registers(result);
+
+      for (final ComputationCompiler cc: param_cc_list)
+      {
+         cc.release_registers(result);
+      }
    }
 
    @Override
@@ -759,10 +867,40 @@ implements tonkadur.fate.v1.lang.meta.InstructionVisitor
    )
    throws Throwable
    {
+      final List<Computation> params;
+      final List<ComputationCompiler> param_cc_list;
       /* This is one dangerous operation to do in-place, so we don't. */
       final Register holder;
       final ComputationCompiler lambda_cc, collection_cc;
 
+      params = new ArrayList<Computation>();
+      param_cc_list = new ArrayList<ComputationCompiler>();
+
+      for
+      (
+         final tonkadur.fate.v1.lang.meta.Computation p:
+            n.get_extra_parameters()
+      )
+      {
+         final ComputationCompiler param_cc;
+
+         param_cc = new ComputationCompiler(compiler);
+
+         p.get_visited_by(param_cc);
+
+         /* Let's not re-compute the parameters on every iteration. */
+         param_cc.generate_address();
+
+         if (param_cc.has_init())
+         {
+            result.add(param_cc.get_init());
+         }
+
+         param_cc_list.add(param_cc);
+
+         params.add(param_cc.get_computation());
+      }
+
       lambda_cc = new ComputationCompiler(compiler);
 
       n.get_lambda_function().get_visited_by(lambda_cc);
@@ -805,13 +943,19 @@ implements tonkadur.fate.v1.lang.meta.InstructionVisitor
             (
                (tonkadur.fate.v1.lang.type.CollectionType)
                n.get_collection().get_type()
-            ).is_set()
+            ).is_set(),
+            params
          )
       );
 
       lambda_cc.release_registers(result);
       collection_cc.release_registers(result);
       compiler.registers().release(holder, result);
+
+      for (final ComputationCompiler cc: param_cc_list)
+      {
+         cc.release_registers(result);
+      }
    }
 
    @Override
@@ -1600,19 +1744,30 @@ implements tonkadur.fate.v1.lang.meta.InstructionVisitor
        *
        * Wyrd (ifelse c0 i0 (nop))
        */
+      final List<Instruction> instructions;
       final ComputationCompiler cc;
-      final InstructionCompiler if_true_ic;
 
+      instructions = new ArrayList<Instruction>();
       cc = new ComputationCompiler(compiler);
-      if_true_ic = new InstructionCompiler(compiler);
 
       n.get_condition().get_visited_by(cc);
 
       compiler.registers().push_hierarchical_instruction_level();
-      n.get_if_true().get_visited_by(if_true_ic);
+
+      for (final tonkadur.fate.v1.lang.meta.Instruction instr: n.get_if_true())
+      {
+         final InstructionCompiler if_true_ic;
+
+         if_true_ic = new InstructionCompiler(compiler);
+
+         instr.get_visited_by(if_true_ic);
+
+         instructions.add(if_true_ic.get_result());
+      }
+
       compiler.registers().pop_hierarchical_instruction_level
       (
-         if_true_ic.result
+         instructions
       );
 
       if (cc.has_init())
@@ -1627,7 +1782,7 @@ implements tonkadur.fate.v1.lang.meta.InstructionVisitor
             compiler.registers(),
             compiler.assembler(),
             cc.get_computation(),
-            if_true_ic.get_result()
+            compiler.assembler().merge(instructions)
          )
       );
 
diff --git a/src/core/src/tonkadur/wyrd/v1/compiler/util/FilterLambda.java b/src/core/src/tonkadur/wyrd/v1/compiler/util/FilterLambda.java
index 8757fe7..83c947f 100644
--- a/src/core/src/tonkadur/wyrd/v1/compiler/util/FilterLambda.java
+++ b/src/core/src/tonkadur/wyrd/v1/compiler/util/FilterLambda.java
@@ -35,14 +35,13 @@ public class FilterLambda
       final RegisterManager registers,
       final InstructionManager assembler,
       final Computation lambda,
-      final Address collection
+      final Address collection,
+      final List<Computation> extra_params
    )
    {
-      final List<Computation> params;
       final List<Instruction> result, while_body, remove_instructions;
       final Register iterator, index_storage, collection_size, storage;
 
-      params = new ArrayList<Computation>();
       result = new ArrayList<Instruction>();
       while_body = new ArrayList<Instruction>();
       remove_instructions = new ArrayList<Instruction>();
@@ -58,8 +57,9 @@ public class FilterLambda
          new SetValue(collection_size.get_address(), new Size(collection))
       );
 
-      params.add
+      extra_params.add
       (
+         0,
          new ValueOf
          (
             new RelativeAddress
@@ -108,7 +108,7 @@ public class FilterLambda
              * be a set.
              */
             storage.get_address(),
-            params
+            extra_params
          )
       );
 
diff --git a/src/core/src/tonkadur/wyrd/v1/compiler/util/Fold.java b/src/core/src/tonkadur/wyrd/v1/compiler/util/Fold.java
index 1596dff..7e6a225 100644
--- a/src/core/src/tonkadur/wyrd/v1/compiler/util/Fold.java
+++ b/src/core/src/tonkadur/wyrd/v1/compiler/util/Fold.java
@@ -37,15 +37,14 @@ public class Fold
       final Computation lambda,
       final Address storage_address,
       final Address collection_in,
-      final boolean is_foldl
+      final boolean is_foldl,
+      final List<Computation> extra_params
    )
    {
-      final List<Computation> params;
       final List<Instruction> result, while_body;
       final Register iterator, collection_in_size;
       final Computation start_point, end_point, condition, increment;
 
-      params = new ArrayList<Computation>();
       result = new ArrayList<Instruction>();
       while_body = new ArrayList<Instruction>();
 
@@ -64,7 +63,8 @@ public class Fold
          end_point = Constant.ZERO;
          start_point =
             Operation.minus(collection_in_size.get_value(), Constant.ONE);
-         condition = Operation.greater_equal_than(iterator.get_value(), end_point);
+         condition =
+            Operation.greater_equal_than(iterator.get_value(), end_point);
          increment = Operation.minus(iterator.get_value(), Constant.ONE);
       }
 
@@ -80,9 +80,9 @@ public class Fold
 
       result.add(new SetValue(iterator.get_address(), start_point));
 
-      params.add(new ValueOf(storage_address));
-      params.add
+      extra_params.add
       (
+         0,
          new ValueOf
          (
             new RelativeAddress
@@ -95,6 +95,7 @@ public class Fold
             )
          )
       );
+      extra_params.add(0, new ValueOf(storage_address));
 
       while_body.add
       (
@@ -107,7 +108,7 @@ public class Fold
              * be a set.
              */
             storage_address,
-            params
+            extra_params
          )
       );
 
diff --git a/src/core/src/tonkadur/wyrd/v1/compiler/util/IndexedMapLambda.java b/src/core/src/tonkadur/wyrd/v1/compiler/util/IndexedMapLambda.java
index 1ff80d1..869b049 100644
--- a/src/core/src/tonkadur/wyrd/v1/compiler/util/IndexedMapLambda.java
+++ b/src/core/src/tonkadur/wyrd/v1/compiler/util/IndexedMapLambda.java
@@ -37,14 +37,13 @@ public class IndexedMapLambda
       final Computation lambda,
       final Address collection_in,
       final Address collection_out,
-      final boolean to_set
+      final boolean to_set,
+      final List<Computation> extra_params
    )
    {
-      final List<Computation> params;
       final List<Instruction> result, while_body;
       final Register iterator, collection_in_size, storage;
 
-      params = new ArrayList<Computation>();
       result = new ArrayList<Instruction>();
       while_body = new ArrayList<Instruction>();
 
@@ -67,10 +66,10 @@ public class IndexedMapLambda
          )
       );
 
-      params.add(iterator.get_value());
 
-      params.add
+      extra_params.add
       (
+         0,
          new ValueOf
          (
             new RelativeAddress
@@ -82,6 +81,8 @@ public class IndexedMapLambda
          )
       );
 
+      extra_params.add(0, iterator.get_value());
+
       while_body.add
       (
          LambdaEvaluation.generate
@@ -93,7 +94,7 @@ public class IndexedMapLambda
              * be a set.
              */
             storage.get_address(),
-            params
+            extra_params
          )
       );
 
diff --git a/src/core/src/tonkadur/wyrd/v1/compiler/util/MapLambda.java b/src/core/src/tonkadur/wyrd/v1/compiler/util/MapLambda.java
index 580bcb1..0b02130 100644
--- a/src/core/src/tonkadur/wyrd/v1/compiler/util/MapLambda.java
+++ b/src/core/src/tonkadur/wyrd/v1/compiler/util/MapLambda.java
@@ -37,14 +37,13 @@ public class MapLambda
       final Computation lambda,
       final Address collection_in,
       final Address collection_out,
-      final boolean to_set
+      final boolean to_set,
+      final List<Computation> extra_params
    )
    {
-      final List<Computation> params;
       final List<Instruction> result, while_body;
       final Register iterator, collection_in_size, storage;
 
-      params = new ArrayList<Computation>();
       result = new ArrayList<Instruction>();
       while_body = new ArrayList<Instruction>();
 
@@ -67,8 +66,9 @@ public class MapLambda
          )
       );
 
-      params.add
+      extra_params.add
       (
+         0,
          new ValueOf
          (
             new RelativeAddress
@@ -93,7 +93,7 @@ public class MapLambda
              * be a set.
              */
             storage.get_address(),
-            params
+            extra_params
          )
       );
 
diff --git a/src/core/src/tonkadur/wyrd/v1/compiler/util/MergeLambda.java b/src/core/src/tonkadur/wyrd/v1/compiler/util/MergeLambda.java
index f17cf02..d09f05f 100644
--- a/src/core/src/tonkadur/wyrd/v1/compiler/util/MergeLambda.java
+++ b/src/core/src/tonkadur/wyrd/v1/compiler/util/MergeLambda.java
@@ -39,15 +39,14 @@ public class MergeLambda
       final Address collection_in_a,
       final Address collection_in_b,
       final Address collection_out,
-      final boolean to_set
+      final boolean to_set,
+      final List<Computation> extra_params
    )
    {
-      final List<Computation> params;
       final List<Instruction> result, while_body;
       final Register iterator, collection_in_size, storage;
       final Register collection_in_b_size;
 
-      params = new ArrayList<Computation>();
       result = new ArrayList<Instruction>();
       while_body = new ArrayList<Instruction>();
 
@@ -99,28 +98,30 @@ public class MergeLambda
          )
       );
 
-      params.add
+      extra_params.add
       (
+         0,
          new ValueOf
          (
             new RelativeAddress
             (
-               collection_in_a,
+               collection_in_b,
                new Cast(iterator.get_value(), Type.STRING),
-               ((MapType) collection_in_a.get_target_type()).get_member_type()
+               ((MapType) collection_in_b.get_target_type()).get_member_type()
             )
          )
       );
 
-      params.add
+      extra_params.add
       (
+         0,
          new ValueOf
          (
             new RelativeAddress
             (
-               collection_in_b,
+               collection_in_a,
                new Cast(iterator.get_value(), Type.STRING),
-               ((MapType) collection_in_b.get_target_type()).get_member_type()
+               ((MapType) collection_in_a.get_target_type()).get_member_type()
             )
          )
       );
@@ -136,7 +137,7 @@ public class MergeLambda
              * be a set.
              */
             storage.get_address(),
-            params
+            extra_params
          )
       );