...

25 files changed, 399 insertions, 225 deletions

diff --git a/src/core/src/tonkadur/fate/v1/lang/World.java b/src/core/src/tonkadur/fate/v1/lang/World.java
index 34b2364..a5f1bbe 100644
--- a/src/core/src/tonkadur/fate/v1/lang/World.java
+++ b/src/core/src/tonkadur/fate/v1/lang/World.java
@@ -25,8 +25,12 @@ import tonkadur.fate.v1.lang.meta.ExtraComputation;
 import tonkadur.fate.v1.lang.meta.RecurrentChecks;
 import tonkadur.fate.v1.lang.meta.Instruction;
 
-import tonkadur.fate.v1.lang.type.Type;
+import tonkadur.fate.v1.lang.type.CollectionType;
+import tonkadur.fate.v1.lang.type.ConsType;
+import tonkadur.fate.v1.lang.type.DictionaryType;
+import tonkadur.fate.v1.lang.type.LambdaType;
 import tonkadur.fate.v1.lang.type.SequenceType;
+import tonkadur.fate.v1.lang.type.Type;
 
 import tonkadur.fate.v1.lang.computation.SequenceReference;
 
@@ -312,13 +316,24 @@ public class World
       try
       {
          type_collection.add(Type.BOOL);
-         //type_collection.add(Type.DICT);
          type_collection.add(Type.FLOAT);
          type_collection.add(Type.INT);
-         //type_collection.add(Type.LIST);
-         //type_collection.add(Type.SET);
          type_collection.add(Type.STRING);
          type_collection.add(Type.TEXT);
+
+         type_collection.add(CollectionType.LIST_ARCHETYPE);
+         type_collection.add(CollectionType.SET_ARCHETYPE);
+
+         type_collection.add(ConsType.ARCHETYPE);
+
+         type_collection.add(DictionaryType.ARCHETYPE);
+
+         type_collection.add(LambdaType.ARCHETYPE);
+         type_collection.add(SequenceType.ARCHETYPE);
+
+         //type_collection.add(Type.SET);
+         //
+         //type_collection.add(Type.DICT);
       }
       catch (final Throwable t)
       {
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/FieldAccess.java b/src/core/src/tonkadur/fate/v1/lang/computation/FieldAccess.java
index 3949aca..5096ff8 100644
--- a/src/core/src/tonkadur/fate/v1/lang/computation/FieldAccess.java
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/FieldAccess.java
@@ -14,6 +14,7 @@ import tonkadur.fate.v1.lang.meta.ComputationVisitor;
 import tonkadur.fate.v1.lang.meta.Computation;
 
 import tonkadur.fate.v1.lang.type.StructType;
+import tonkadur.fate.v1.lang.type.PointerType;
 import tonkadur.fate.v1.lang.type.Type;
 
 import tonkadur.fate.v1.lang.computation.generic.AtReference;
@@ -60,7 +61,7 @@ public class FieldAccess extends Computation
 
       current_type = parent.get_type();
 
-      while (current_type.get_act_as_type().equals(Type.PTR))
+      while (current_type.get_act_as_type().equals(PointerType.ARCHETYPE))
       {
          parent =
             GenericComputation.build
@@ -81,7 +82,7 @@ public class FieldAccess extends Computation
             (
                origin,
                current_type,
-               Collections.singleton(Type.DICT),
+               Collections.singleton(Type.ANY), // FIXME: Type.STRUCT
                parent.toString()
             )
          );
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/Newline.java b/src/core/src/tonkadur/fate/v1/lang/computation/Newline.java
index b05021d..2f70d3e 100644
--- a/src/core/src/tonkadur/fate/v1/lang/computation/Newline.java
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/Newline.java
@@ -3,9 +3,11 @@ package tonkadur.fate.v1.lang.computation;
 import tonkadur.parser.Origin;
 
 import tonkadur.fate.v1.lang.meta.ComputationVisitor;
-import tonkadur.fate.v1.lang.meta.TextNode;
+import tonkadur.fate.v1.lang.meta.Computation;
 
-public class Newline extends TextNode
+import tonkadur.fate.v1.lang.type.Type;
+
+public class Newline extends Computation
 {
    /***************************************************************************/
    /**** PUBLIC ***************************************************************/
@@ -13,7 +15,7 @@ public class Newline extends TextNode
    /**** Constructors *********************************************************/
    public Newline (final Origin origin)
    {
-      super(origin);
+      super(origin, Type.TEXT);
    }
 
    /**** Accessors ************************************************************/
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/Paragraph.java b/src/core/src/tonkadur/fate/v1/lang/computation/Paragraph.java
index f2959b2..db8e2cb 100644
--- a/src/core/src/tonkadur/fate/v1/lang/computation/Paragraph.java
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/Paragraph.java
@@ -6,9 +6,9 @@ import tonkadur.parser.Origin;
 
 import tonkadur.fate.v1.lang.meta.ComputationVisitor;
 import tonkadur.fate.v1.lang.meta.Computation;
-import tonkadur.fate.v1.lang.meta.TextNode;
+import tonkadur.fate.v1.lang.type.Type;
 
-public class Paragraph extends TextNode
+public class Paragraph extends Computation
 {
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
@@ -30,7 +30,7 @@ public class Paragraph extends TextNode
       final List<Computation> content
    )
    {
-      super(origin);
+      super(origin, Type.TEXT);
 
       this.content = content;
    }
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/TextWithEffect.java b/src/core/src/tonkadur/fate/v1/lang/computation/TextWithEffect.java
index 17fda37..d5647c0 100644
--- a/src/core/src/tonkadur/fate/v1/lang/computation/TextWithEffect.java
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/TextWithEffect.java
@@ -8,18 +8,19 @@ import tonkadur.parser.ParsingError;
 import tonkadur.fate.v1.lang.TextEffect;
 
 import tonkadur.fate.v1.lang.meta.ComputationVisitor;
-import tonkadur.fate.v1.lang.meta.TextNode;
 import tonkadur.fate.v1.lang.meta.Computation;
 import tonkadur.fate.v1.lang.meta.RecurrentChecks;
 
-public class TextWithEffect extends TextNode
+import tonkadur.fate.v1.lang.type.Type;
+
+public class TextWithEffect extends Computation
 {
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
    protected final TextEffect effect;
    protected final List<Computation> parameters;
-   protected final TextNode text;
+   protected final Computation text;
 
    /***************************************************************************/
    /**** PROTECTED ************************************************************/
@@ -30,10 +31,10 @@ public class TextWithEffect extends TextNode
       final Origin origin,
       final TextEffect effect,
       final List<Computation> parameters,
-      final TextNode text
+      final Computation text
    )
    {
-      super(origin);
+      super(origin, Type.TEXT);
 
       this.effect = effect;
       this.parameters = parameters;
@@ -49,7 +50,7 @@ public class TextWithEffect extends TextNode
       final Origin origin,
       final TextEffect effect,
       final List<Computation> parameters,
-      final TextNode text
+      final Computation text
    )
    throws ParsingError
    {
@@ -81,7 +82,7 @@ public class TextWithEffect extends TextNode
       return parameters;
    }
 
-   public TextNode get_text ()
+   public Computation get_text ()
    {
       return text;
    }
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/ValueToText.java b/src/core/src/tonkadur/fate/v1/lang/computation/ValueToText.java
index e81f8cd..ad4f8a3 100644
--- a/src/core/src/tonkadur/fate/v1/lang/computation/ValueToText.java
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/ValueToText.java
@@ -8,10 +8,9 @@ import tonkadur.fate.v1.error.IncomparableTypeException;
 import tonkadur.fate.v1.lang.type.Type;
 
 import tonkadur.fate.v1.lang.meta.ComputationVisitor;
-import tonkadur.fate.v1.lang.meta.TextNode;
 import tonkadur.fate.v1.lang.meta.Computation;
 
-public class ValueToText extends TextNode
+public class ValueToText extends Computation
 {
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
@@ -24,7 +23,7 @@ public class ValueToText extends TextNode
    /**** Constructors *********************************************************/
    protected ValueToText (final Computation value)
    {
-      super(value.get_origin());
+      super(value.get_origin(), Type.TEXT);
 
       this.value = value;
    }
diff --git a/src/core/src/tonkadur/fate/v1/lang/computation/generic/AtReference.java b/src/core/src/tonkadur/fate/v1/lang/computation/generic/AtReference.java
index ec81da7..158cde6 100644
--- a/src/core/src/tonkadur/fate/v1/lang/computation/generic/AtReference.java
+++ b/src/core/src/tonkadur/fate/v1/lang/computation/generic/AtReference.java
@@ -121,7 +121,7 @@ public class AtReference extends GenericComputation
             (
                origin,
                current_type,
-               Collections.singleton(Type.PTR)
+               Collections.singleton(PointerType.ARCHETYPE)
             )
          );
 
diff --git a/src/core/src/tonkadur/fate/v1/lang/instruction/Assert.java b/src/core/src/tonkadur/fate/v1/lang/instruction/Assert.java
index 4a6e7bc..3ec088e 100644
--- a/src/core/src/tonkadur/fate/v1/lang/instruction/Assert.java
+++ b/src/core/src/tonkadur/fate/v1/lang/instruction/Assert.java
@@ -5,7 +5,6 @@ import tonkadur.parser.ParsingError;
 
 import tonkadur.fate.v1.lang.meta.InstructionVisitor;
 import tonkadur.fate.v1.lang.meta.Instruction;
-import tonkadur.fate.v1.lang.meta.TextNode;
 import tonkadur.fate.v1.lang.meta.Computation;
 import tonkadur.fate.v1.lang.meta.RecurrentChecks;
 
@@ -17,7 +16,7 @@ public class Assert extends Instruction
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
    protected final Computation condition;
-   protected final TextNode message;
+   protected final Computation message;
 
    /***************************************************************************/
    /**** PROTECTED ************************************************************/
@@ -27,7 +26,7 @@ public class Assert extends Instruction
    (
       final Origin origin,
       final Computation condition,
-      final TextNode message
+      final Computation message
    )
    {
       super(origin);
@@ -44,7 +43,7 @@ public class Assert extends Instruction
    (
       final Origin origin,
       final Computation condition,
-      final TextNode message
+      final Computation message
    )
    throws ParsingError
    {
@@ -66,7 +65,7 @@ public class Assert extends Instruction
       return condition;
    }
 
-   public TextNode get_message ()
+   public Computation get_message ()
    {
       return message;
    }
diff --git a/src/core/src/tonkadur/fate/v1/lang/instruction/Display.java b/src/core/src/tonkadur/fate/v1/lang/instruction/Display.java
index 5e85d79..3d5d7ce 100644
--- a/src/core/src/tonkadur/fate/v1/lang/instruction/Display.java
+++ b/src/core/src/tonkadur/fate/v1/lang/instruction/Display.java
@@ -10,14 +10,14 @@ import tonkadur.fate.v1.lang.type.Type;
 
 import tonkadur.fate.v1.lang.meta.InstructionVisitor;
 import tonkadur.fate.v1.lang.meta.Instruction;
-import tonkadur.fate.v1.lang.meta.TextNode;
+import tonkadur.fate.v1.lang.meta.Computation;
 
 public class Display extends Instruction
 {
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
-   protected final TextNode content;
+   protected final Computation content;
 
    /***************************************************************************/
    /**** PROTECTED ************************************************************/
@@ -26,7 +26,7 @@ public class Display extends Instruction
    public Display
    (
       final Origin origin,
-      final TextNode content
+      final Computation content
    )
    {
       super(origin);
@@ -47,7 +47,7 @@ public class Display extends Instruction
       iv.visit_display(this);
    }
 
-   public TextNode get_content ()
+   public Computation get_content ()
    {
       return content;
    }
diff --git a/src/core/src/tonkadur/fate/v1/lang/instruction/SequenceVariableCall.java b/src/core/src/tonkadur/fate/v1/lang/instruction/SequenceVariableCall.java
index 407f430..e834aaf 100644
--- a/src/core/src/tonkadur/fate/v1/lang/instruction/SequenceVariableCall.java
+++ b/src/core/src/tonkadur/fate/v1/lang/instruction/SequenceVariableCall.java
@@ -62,7 +62,7 @@ public class SequenceVariableCall extends Instruction
          parameters
       );
 
-      if (!sequence.get_type().get_act_as_type().equals(Type.SEQUENCE))
+      if (!sequence.get_type().get_act_as_type().equals(SequenceType.ARCHETYPE))
       {
          ErrorManager.handle
          (
@@ -70,7 +70,7 @@ public class SequenceVariableCall extends Instruction
             (
                origin,
                sequence.get_type(),
-               Collections.singleton(Type.SEQUENCE)
+               Collections.singleton(SequenceType.ARCHETYPE)
             )
          );
       }
diff --git a/src/core/src/tonkadur/fate/v1/lang/instruction/SequenceVariableJump.java b/src/core/src/tonkadur/fate/v1/lang/instruction/SequenceVariableJump.java
index 52aa947..483ff95 100644
--- a/src/core/src/tonkadur/fate/v1/lang/instruction/SequenceVariableJump.java
+++ b/src/core/src/tonkadur/fate/v1/lang/instruction/SequenceVariableJump.java
@@ -62,7 +62,7 @@ public class SequenceVariableJump extends Instruction
          parameters
       );
 
-      if (!sequence.get_type().get_act_as_type().equals(Type.SEQUENCE))
+      if (!sequence.get_type().get_act_as_type().equals(SequenceType.ARCHETYPE))
       {
          ErrorManager.handle
          (
@@ -70,7 +70,7 @@ public class SequenceVariableJump extends Instruction
             (
                origin,
                sequence.get_type(),
-               Collections.singleton(Type.SEQUENCE)
+               Collections.singleton(SequenceType.ARCHETYPE)
             )
          );
       }
diff --git a/src/core/src/tonkadur/fate/v1/lang/instruction/TextOption.java b/src/core/src/tonkadur/fate/v1/lang/instruction/TextOption.java
index 9a1774d..e612a08 100644
--- a/src/core/src/tonkadur/fate/v1/lang/instruction/TextOption.java
+++ b/src/core/src/tonkadur/fate/v1/lang/instruction/TextOption.java
@@ -8,14 +8,14 @@ import tonkadur.fate.v1.lang.type.Type;
 
 import tonkadur.fate.v1.lang.meta.InstructionVisitor;
 import tonkadur.fate.v1.lang.meta.Instruction;
-import tonkadur.fate.v1.lang.meta.TextNode;
+import tonkadur.fate.v1.lang.meta.Computation;
 
 public class TextOption extends Instruction
 {
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
-   protected final TextNode text;
+   protected final Computation text;
    protected final List<Instruction> effects;
 
    /***************************************************************************/
@@ -25,7 +25,7 @@ public class TextOption extends Instruction
    public TextOption
    (
       final Origin origin,
-      final TextNode text,
+      final Computation text,
       final List<Instruction> effects
    )
    {
@@ -44,7 +44,7 @@ public class TextOption extends Instruction
       iv.visit_text_option(this);
    }
 
-   public TextNode get_text ()
+   public Computation get_text ()
    {
       return text;
    }
diff --git a/src/core/src/tonkadur/fate/v1/lang/meta/RecurrentChecks.java b/src/core/src/tonkadur/fate/v1/lang/meta/RecurrentChecks.java
index 01925f7..b8ab9a6 100644
--- a/src/core/src/tonkadur/fate/v1/lang/meta/RecurrentChecks.java
+++ b/src/core/src/tonkadur/fate/v1/lang/meta/RecurrentChecks.java
@@ -101,7 +101,7 @@ public class RecurrentChecks
             (
                o,
                t,
-               Collections.singletonList(Type.LIST)
+               Collections.singletonList(CollectionType.LIST_ARCHETYPE)
             )
          );
       }
@@ -128,7 +128,7 @@ public class RecurrentChecks
             (
                o,
                t,
-               Collections.singletonList(Type.SET)
+               Collections.singletonList(CollectionType.SET_ARCHETYPE)
             )
          );
       }
@@ -372,7 +372,7 @@ public class RecurrentChecks
             (
                l.get_origin(),
                l.get_type(),
-               Collections.singleton(Type.LAMBDA)
+               Collections.singleton(LambdaType.ARCHETYPE)
             )
          );
       }
diff --git a/src/core/src/tonkadur/fate/v1/lang/meta/TextNode.java b/src/core/src/tonkadur/fate/v1/lang/meta/TextNode.java
deleted file mode 100644
index eec40bb..0000000
--- a/src/core/src/tonkadur/fate/v1/lang/meta/TextNode.java
+++ /dev/null
@@ -1,25 +0,0 @@
-package tonkadur.fate.v1.lang.meta;
-
-import tonkadur.parser.Origin;
-
-import tonkadur.fate.v1.lang.type.Type;
-
-
-public abstract class TextNode extends Computation
-{
-   /***************************************************************************/
-   /**** PROTECTED ************************************************************/
-   /***************************************************************************/
-   /**** Constructors *********************************************************/
-   protected TextNode (final Origin origin)
-   {
-      super(origin, Type.TEXT);
-   }
-
-   /***************************************************************************/
-   /**** PUBLIC ***************************************************************/
-   /***************************************************************************/
-   /**** Constructors *********************************************************/
-   /**** Accessors ************************************************************/
-   /**** Misc. ****************************************************************/
-}
diff --git a/src/core/src/tonkadur/fate/v1/lang/type/CollectionType.java b/src/core/src/tonkadur/fate/v1/lang/type/CollectionType.java
index 443bc84..eb8b664 100644
--- a/src/core/src/tonkadur/fate/v1/lang/type/CollectionType.java
+++ b/src/core/src/tonkadur/fate/v1/lang/type/CollectionType.java
@@ -1,5 +1,7 @@
 package tonkadur.fate.v1.lang.type;
 
+import java.util.Collections;
+
 import tonkadur.error.ErrorManager;
 import tonkadur.parser.ParsingError;
 
@@ -11,10 +13,33 @@ import tonkadur.fate.v1.lang.meta.DeclaredEntity;
 
 public class CollectionType extends Type
 {
+   public static final CollectionType LIST_ARCHETYPE;
+   public static final CollectionType SET_ARCHETYPE;
+
+   static
+   {
+
+      LIST_ARCHETYPE =
+         new CollectionType
+         (
+            Origin.BASE_LANGUAGE,
+            Type.ANY,
+            false,
+            "list"
+         );
+
+      SET_ARCHETYPE =
+         new CollectionType
+         (
+            Origin.BASE_LANGUAGE,
+            Type.ANY,
+            true,
+            "set"
+         );
+   }
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
-   protected final Type content_type;
    protected final boolean is_set;
 
    /***************************************************************************/
@@ -59,7 +84,7 @@ public class CollectionType extends Type
    /**** Accessors ************************************************************/
    public Type get_content_type ()
    {
-      return content_type;
+      return parameters.get(0);
    }
 
    public boolean is_set ()
@@ -70,7 +95,7 @@ public class CollectionType extends Type
    @Override
    public Type get_act_as_type ()
    {
-      return is_set? Type.SET : Type.LIST;
+      return is_set()? SET_ARCHETYPE: LIST_ARCHETYPE;
    }
 
    /**** Compatibility ********************************************************/
@@ -85,8 +110,8 @@ public class CollectionType extends Type
 
          return
             (
-               (!ct.is_set || is_set)
-               && content_type.can_be_used_as(ct.content_type)
+               (!ct.is_set() || is_set())
+               && get_content_type().can_be_used_as(ct.get_content_type())
             );
       }
 
@@ -115,8 +140,14 @@ public class CollectionType extends Type
          new CollectionType
          (
             get_origin(),
-            ((Type) content_type.generate_comparable_to(ct.content_type)),
-            (ct.is_set || is_set),
+            (
+               (Type) get_content_type().generate_comparable_to
+               (
+                  ct.get_content_type()
+               )
+            ),
+            // FIXME: not too sure about that line there:
+            ct.is_set(),
             name
          );
    }
@@ -126,7 +157,7 @@ public class CollectionType extends Type
    @Override
    public Type generate_alias (final Origin origin, final String name)
    {
-      return new CollectionType(origin, content_type, is_set, name);
+      return new CollectionType(origin, get_content_type(), is_set(), name);
    }
 
    @Override
@@ -143,9 +174,9 @@ public class CollectionType extends Type
          sb.append("(List ");
       }
 
-      sb.append(content_type.toString());
+      sb.append(get_content_type().toString());
       sb.append(")::");
-      sb.append(name);
+      sb.append(get_name());
 
       return sb.toString();
    }
@@ -163,9 +194,8 @@ public class CollectionType extends Type
       final String name
    )
    {
-      super(origin, null, name);
+      super(origin, null, name, Collections.singletonList(content_type));
 
       this.is_set = is_set;
-      this.content_type = content_type;
    }
 }
diff --git a/src/core/src/tonkadur/fate/v1/lang/type/ConsType.java b/src/core/src/tonkadur/fate/v1/lang/type/ConsType.java
index e01a91b..7fe5a34 100644
--- a/src/core/src/tonkadur/fate/v1/lang/type/ConsType.java
+++ b/src/core/src/tonkadur/fate/v1/lang/type/ConsType.java
@@ -1,16 +1,27 @@
 package tonkadur.fate.v1.lang.type;
 
+import java.util.Arrays;
+
 import tonkadur.parser.Origin;
 
 import tonkadur.fate.v1.lang.meta.DeclaredEntity;
 
 public class ConsType extends Type
 {
-   /***************************************************************************/
-   /**** MEMBERS **************************************************************/
-   /***************************************************************************/
-   protected final Type car;
-   protected final Type cdr;
+   public static final ConsType ARCHETYPE;
+
+   static
+   {
+
+      ARCHETYPE =
+         new ConsType
+         (
+            Origin.BASE_LANGUAGE,
+            Type.ANY,
+            Type.ANY,
+            "cons"
+         );
+   }
 
    /***************************************************************************/
    /**** PUBLIC ***************************************************************/
@@ -25,21 +36,18 @@ public class ConsType extends Type
       final String name
    )
    {
-      super(origin, null, name);
-
-      this.car = car;
-      this.cdr = cdr;
+      super(origin, null, name, Arrays.asList(new Type[]{car, cdr}));
    }
 
    /**** Accessors ************************************************************/
    public Type get_car_type ()
    {
-      return car;
+      return parameters.get(0);
    }
 
    public Type get_cdr_type ()
    {
-      return cdr;
+      return parameters.get(1);
    }
 
    /**** Compatibility ********************************************************/
@@ -53,8 +61,8 @@ public class ConsType extends Type
          dt = (ConsType) t;
 
          return
-            car.can_be_used_as(dt.car)
-            && cdr.can_be_used_as(dt.cdr);
+            get_car_type().can_be_used_as(dt.get_car_type())
+            && get_cdr_type().can_be_used_as(dt.get_cdr_type());
       }
 
       return false;
@@ -79,8 +87,11 @@ public class ConsType extends Type
 
       dt = (ConsType) de;
 
-      resulting_car = (Type) car.generate_comparable_to(dt.car);
-      resulting_cdr = (Type) cdr.generate_comparable_to(dt.cdr);
+      resulting_car =
+         (Type) get_car_type().generate_comparable_to(dt.get_car_type());
+
+      resulting_cdr =
+         (Type) get_cdr_type().generate_comparable_to(dt.get_cdr_type());
 
       return new ConsType(get_origin(), resulting_car, resulting_cdr, name);
    }
@@ -88,14 +99,14 @@ public class ConsType extends Type
    @Override
    public Type get_act_as_type ()
    {
-      return Type.CONS;
+      return ARCHETYPE;
    }
 
    /**** Misc. ****************************************************************/
    @Override
    public Type generate_alias (final Origin origin, final String name)
    {
-      return new ConsType(origin, car, cdr, name);
+      return new ConsType(origin, get_car_type(), get_cdr_type(), name);
    }
 
    @Override
@@ -104,9 +115,9 @@ public class ConsType extends Type
       final StringBuilder sb = new StringBuilder();
 
       sb.append("(Cons ");
-      sb.append(car.toString());
+      sb.append(get_car_type().toString());
       sb.append(" ");
-      sb.append(cdr.toString());
+      sb.append(get_cdr_type().toString());
       sb.append(")::");
       sb.append(name);
 
diff --git a/src/core/src/tonkadur/fate/v1/lang/type/DictionaryType.java b/src/core/src/tonkadur/fate/v1/lang/type/DictionaryType.java
index a1f6041..18f0a0e 100644
--- a/src/core/src/tonkadur/fate/v1/lang/type/DictionaryType.java
+++ b/src/core/src/tonkadur/fate/v1/lang/type/DictionaryType.java
@@ -11,6 +11,20 @@ import tonkadur.fate.v1.lang.meta.DeclaredEntity;
 
 public class DictionaryType extends Type
 {
+   public static final DictionaryType ARCHETYPE;
+
+   static
+   {
+      ARCHETYPE =
+         new DictionaryType
+         (
+            Origin.BASE_LANGUAGE,
+            Type.ANY,
+            Type.ANY,
+            "dict"
+         );
+   }
+
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
@@ -57,7 +71,7 @@ public class DictionaryType extends Type
    @Override
    public Type get_act_as_type ()
    {
-      return Type.DICT;
+      return ARCHETYPE;
    }
 
    /**** Compatibility ********************************************************/
diff --git a/src/core/src/tonkadur/fate/v1/lang/type/ExtraType.java b/src/core/src/tonkadur/fate/v1/lang/type/ExtraType.java
index 91543fc..aed727f 100644
--- a/src/core/src/tonkadur/fate/v1/lang/type/ExtraType.java
+++ b/src/core/src/tonkadur/fate/v1/lang/type/ExtraType.java
@@ -1,6 +1,8 @@
 package tonkadur.fate.v1.lang.type;
 
 import java.util.List;
+import java.util.HashMap;
+import java.util.Map;
 
 import tonkadur.parser.Origin;
 
@@ -10,10 +12,6 @@ import tonkadur.fate.v1.lang.meta.RecurrentChecks;
 public class ExtraType extends Type
 {
    /***************************************************************************/
-   /**** MEMBERS **************************************************************/
-   /***************************************************************************/
-   protected final List<Type> parameters;
-   /***************************************************************************/
    /**** PUBLIC ***************************************************************/
    /***************************************************************************/
 
@@ -21,26 +19,12 @@ public class ExtraType extends Type
    public ExtraType
    (
       final Origin origin,
-      final String name,
-      final List<Type> parameters
-   )
-   {
-      super(origin, null, name);
-
-      this.parameters = parameters;
-   }
-
-   public ExtraType
-   (
-      final Origin origin,
       final ExtraType parent,
       final String name,
       final List<Type> parameters
    )
    {
-      super(origin, parent, name);
-
-      this.parameters = parameters;
+      super(origin, parent, name, parameters);
    }
 
    /**** Accessors ************************************************************/
@@ -97,8 +81,12 @@ public class ExtraType extends Type
       return get_base_type();
    }
 
-   /**** Misc. ****************************************************************/
+   public List<Type> get_parameters ()
+   {
+      return parameters;
+   }
 
+   /**** Misc. ****************************************************************/
    @Override
    public Type generate_alias (final Origin origin, final String name)
    {
diff --git a/src/core/src/tonkadur/fate/v1/lang/type/LambdaType.java b/src/core/src/tonkadur/fate/v1/lang/type/LambdaType.java
index a434112..1a6a111 100644
--- a/src/core/src/tonkadur/fate/v1/lang/type/LambdaType.java
+++ b/src/core/src/tonkadur/fate/v1/lang/type/LambdaType.java
@@ -10,10 +10,23 @@ import tonkadur.fate.v1.lang.meta.DeclaredEntity;
 
 public class LambdaType extends Type
 {
+   public static final LambdaType ARCHETYPE;
+
+   static
+   {
+      ARCHETYPE =
+         new LambdaType
+         (
+            Origin.BASE_LANGUAGE,
+            Type.ANY,
+            "lambda",
+            new ArrayList<Type>()
+         );
+   }
+
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
-   protected final List<Type> signature;
    protected final Type return_type;
 
    /***************************************************************************/
@@ -29,9 +42,8 @@ public class LambdaType extends Type
       final List<Type> signature
    )
    {
-      super(origin, null, name);
+      super(origin, null, name, signature);
 
-      this.signature = signature;
       this.return_type = return_type;
    }
 
@@ -43,7 +55,7 @@ public class LambdaType extends Type
 
    public List<Type> get_signature ()
    {
-      return signature;
+      return parameters;
    }
 
    /**** Compatibility ********************************************************/
@@ -59,15 +71,15 @@ public class LambdaType extends Type
 
          if
          (
-            signature.size() != lt.signature.size()
+            parameters.size() != lt.parameters.size()
             || !return_type.can_be_used_as(lt.return_type)
          )
          {
             return false;
          }
 
-         i0 = signature.iterator();
-         i1 = lt.signature.iterator();
+         i0 = parameters.iterator();
+         i1 = lt.parameters.iterator();
 
          while(i0.hasNext())
          {
@@ -104,7 +116,7 @@ public class LambdaType extends Type
 
       lt = (LambdaType) de;
 
-      if (lt.signature.size() != signature.size())
+      if (lt.parameters.size() != parameters.size())
       {
          return Type.ANY;
       }
@@ -113,8 +125,8 @@ public class LambdaType extends Type
       resulting_return_type =
          (Type) return_type.generate_comparable_to(lt.return_type);
 
-      i0 = signature.iterator();
-      i1 = lt.signature.iterator();
+      i0 = parameters.iterator();
+      i1 = lt.parameters.iterator();
 
       while(i0.hasNext())
       {
@@ -137,14 +149,14 @@ public class LambdaType extends Type
    @Override
    public Type get_act_as_type ()
    {
-      return Type.LAMBDA;
+      return get_base_type();
    }
 
    /**** Misc. ****************************************************************/
    @Override
    public Type generate_alias (final Origin origin, final String name)
    {
-      return new LambdaType(origin, return_type, name, signature);
+      return new LambdaType(origin, return_type, name, parameters);
    }
 
    @Override
@@ -156,7 +168,7 @@ public class LambdaType extends Type
       sb.append(return_type.toString());
       sb.append(" (");
 
-      for (final Type t: signature)
+      for (final Type t: parameters)
       {
          sb.append(t.get_name());
       }
diff --git a/src/core/src/tonkadur/fate/v1/lang/type/PointerType.java b/src/core/src/tonkadur/fate/v1/lang/type/PointerType.java
index 0269cf7..db1a18a 100644
--- a/src/core/src/tonkadur/fate/v1/lang/type/PointerType.java
+++ b/src/core/src/tonkadur/fate/v1/lang/type/PointerType.java
@@ -1,15 +1,29 @@
 package tonkadur.fate.v1.lang.type;
 
+import java.util.Collections;
+
 import tonkadur.parser.Origin;
 
 import tonkadur.fate.v1.lang.meta.DeclaredEntity;
 
 public class PointerType extends Type
 {
+   public static final PointerType ARCHETYPE;
+
+   static
+   {
+      ARCHETYPE =
+         new PointerType
+         (
+            Origin.BASE_LANGUAGE,
+            Type.ANY,
+            "ptr"
+         );
+   }
+
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
-   protected final Type referenced_type;
 
    /***************************************************************************/
    /**** PUBLIC ***************************************************************/
@@ -23,15 +37,13 @@ public class PointerType extends Type
       final String name
    )
    {
-      super(origin, null, name);
-
-      this.referenced_type = referenced_type;
+      super(origin, null, name, Collections.singletonList(referenced_type));
    }
 
    /**** Accessors ************************************************************/
    public Type get_referenced_type ()
    {
-      return referenced_type;
+      return parameters.get(0);
    }
 
    /**** Compatibility ********************************************************/
@@ -44,7 +56,7 @@ public class PointerType extends Type
 
          dt = (PointerType) t;
 
-         return referenced_type.can_be_used_as(dt.referenced_type);
+         return get_referenced_type().can_be_used_as(dt.get_referenced_type());
       }
 
       return false;
@@ -69,7 +81,10 @@ public class PointerType extends Type
 
       dt = (PointerType) de;
       resulting_referenced_type =
-         (Type) referenced_type.generate_comparable_to(dt.referenced_type);
+         (Type) get_referenced_type().generate_comparable_to
+         (
+            dt.get_referenced_type()
+         );
 
       return new PointerType(get_origin(), resulting_referenced_type, name);
    }
@@ -77,14 +92,14 @@ public class PointerType extends Type
    @Override
    public Type get_act_as_type ()
    {
-      return Type.PTR;
+      return ARCHETYPE;
    }
 
    /**** Misc. ****************************************************************/
    @Override
    public Type generate_alias (final Origin origin, final String name)
    {
-      return new PointerType(origin, referenced_type, name);
+      return new PointerType(origin, get_referenced_type(), name);
    }
 
    @Override
@@ -93,7 +108,7 @@ public class PointerType extends Type
       final StringBuilder sb = new StringBuilder();
 
       sb.append("(Pointer to ");
-      sb.append(referenced_type.toString());
+      sb.append(get_referenced_type().toString());
       sb.append(")::");
       sb.append(name);
 
diff --git a/src/core/src/tonkadur/fate/v1/lang/type/SequenceType.java b/src/core/src/tonkadur/fate/v1/lang/type/SequenceType.java
index c6e7ef3..0970a98 100644
--- a/src/core/src/tonkadur/fate/v1/lang/type/SequenceType.java
+++ b/src/core/src/tonkadur/fate/v1/lang/type/SequenceType.java
@@ -11,10 +11,22 @@ import tonkadur.fate.v1.lang.meta.Computation;
 
 public class SequenceType extends Type
 {
+   public static final SequenceType ARCHETYPE;
+
+   static
+   {
+      ARCHETYPE =
+         new SequenceType
+         (
+            Origin.BASE_LANGUAGE,
+            "sequence",
+            new ArrayList<Type>()
+         );
+   }
+
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
-   protected final List<Type> signature;
    protected boolean signature_is_defined;
 
    /***************************************************************************/
@@ -26,12 +38,11 @@ public class SequenceType extends Type
    (
       final Origin origin,
       final String name,
-      final List<Type> signature
+      final List<Type> parameters
    )
    {
-      super(origin, null, name);
+      super(origin, null, name, parameters);
 
-      this.signature = signature;
       this.signature_is_defined = true;
    }
 
@@ -41,16 +52,15 @@ public class SequenceType extends Type
       final String name
    )
    {
-      super(origin, null, name);
+      super(origin, null, name, new ArrayList<Type>());
 
-      this.signature = new ArrayList<Type>();
       this.signature_is_defined = false;
    }
 
    /**** Accessors ************************************************************/
    public List<Type> get_signature ()
    {
-      return signature;
+      return parameters;
    }
 
    public void propose_signature (final List<Type> signature)
@@ -60,7 +70,7 @@ public class SequenceType extends Type
          return;
       }
 
-      this.signature.addAll(signature);
+      this.parameters.addAll(signature);
 
       signature_is_defined = true;
    }
@@ -77,7 +87,7 @@ public class SequenceType extends Type
 
       for (final Computation c: params)
       {
-         signature.add(c.get_type());
+         parameters.add(c.get_type());
       }
 
       signature_is_defined = true;
@@ -96,13 +106,13 @@ public class SequenceType extends Type
 
          propose_signature(lt.get_signature());
 
-         if (signature.size() != lt.signature.size())
+         if (parameters.size() != lt.parameters.size())
          {
             return false;
          }
 
-         i0 = signature.iterator();
-         i1 = lt.signature.iterator();
+         i0 = parameters.iterator();
+         i1 = lt.parameters.iterator();
 
          while(i0.hasNext())
          {
@@ -138,15 +148,15 @@ public class SequenceType extends Type
 
       lt = (SequenceType) de;
 
-      if (lt.signature.size() != signature.size())
+      if (lt.parameters.size() != parameters.size())
       {
          return Type.ANY;
       }
 
       resulting_signature = new ArrayList<Type>();
 
-      i0 = signature.iterator();
-      i1 = lt.signature.iterator();
+      i0 = parameters.iterator();
+      i1 = lt.parameters.iterator();
 
       while(i0.hasNext())
       {
@@ -162,14 +172,14 @@ public class SequenceType extends Type
    @Override
    public Type get_act_as_type ()
    {
-      return Type.SEQUENCE;
+      return ARCHETYPE;
    }
 
    /**** Misc. ****************************************************************/
    @Override
    public Type generate_alias (final Origin origin, final String name)
    {
-      return new SequenceType(origin, name, signature);
+      return new SequenceType(origin, name, parameters);
    }
 
    @Override
@@ -179,7 +189,7 @@ public class SequenceType extends Type
 
       sb.append("(Sequence (");
 
-      for (final Type t: signature)
+      for (final Type t: parameters)
       {
          sb.append(t.get_name());
          sb.append(" ");
diff --git a/src/core/src/tonkadur/fate/v1/lang/type/StructType.java b/src/core/src/tonkadur/fate/v1/lang/type/StructType.java
index c44e7f4..1d9ab89 100644
--- a/src/core/src/tonkadur/fate/v1/lang/type/StructType.java
+++ b/src/core/src/tonkadur/fate/v1/lang/type/StructType.java
@@ -154,7 +154,7 @@ public class StructType extends Type
    @Override
    public Type get_act_as_type ()
    {
-      return Type.DICT;
+      return get_base_type();
    }
 
    /**** Misc. ****************************************************************/
diff --git a/src/core/src/tonkadur/fate/v1/lang/type/Type.java b/src/core/src/tonkadur/fate/v1/lang/type/Type.java
index 4385ed0..be9901b 100644
--- a/src/core/src/tonkadur/fate/v1/lang/type/Type.java
+++ b/src/core/src/tonkadur/fate/v1/lang/type/Type.java
@@ -21,17 +21,10 @@ public class Type extends DeclaredEntity
 {
    public static final Type ANY;
    public static final Type BOOL;
-   public static final Type CONS;
-   public static final Type DICT;
    public static final Type FLOAT;
    public static final Type INT;
-   public static final Type LAMBDA;
-   public static final Type LIST;
-   public static final Type PTR;
-   public static final Type TEXT;
-   public static final Type SEQUENCE;
-   public static final Type SET;
    public static final Type STRING;
+   public static final Type TEXT;
 
    public static final Set<Type> NUMBER_TYPES;
    public static final Set<Type> ALL_TYPES;
@@ -50,31 +43,24 @@ public class Type extends DeclaredEntity
       ANY = new Type(base, null, "undetermined type");
 
       BOOL = new Type(base, null, "bool");
-      CONS = new Type(base, null, "cons");
-      DICT = new Type(base, null, "dict");
       FLOAT = new Type(base, null, "float");
       INT = new Type(base, null, "int");
-      LAMBDA = new Type(base, null, "lambda");
-      LIST = new Type(base, null, "list");
-      PTR = new Type(base, null, "ptr");
       TEXT = new Type(base, null, "text");
-      SEQUENCE = new Type(base, null, "sequence");
-      SET = new Type(base, null, "set");
       STRING = new Type(base, null, "string");
 
       ALL_TYPES = new HashSet<Type>();
       ALL_TYPES.add(ANY);
       ALL_TYPES.add(BOOL);
-      ALL_TYPES.add(CONS);
-      ALL_TYPES.add(DICT);
+      ALL_TYPES.add(ConsType.ARCHETYPE);
+      ALL_TYPES.add(DictionaryType.ARCHETYPE);
       ALL_TYPES.add(FLOAT);
       ALL_TYPES.add(INT);
-      ALL_TYPES.add(LAMBDA);
-      ALL_TYPES.add(LIST);
-      ALL_TYPES.add(PTR);
+      ALL_TYPES.add(LambdaType.ARCHETYPE);
+      ALL_TYPES.add(CollectionType.SET_ARCHETYPE);
+      ALL_TYPES.add(CollectionType.LIST_ARCHETYPE);
+      ALL_TYPES.add(PointerType.ARCHETYPE);
       ALL_TYPES.add(TEXT);
-      ALL_TYPES.add(SEQUENCE);
-      ALL_TYPES.add(SET);
+      ALL_TYPES.add(SequenceType.ARCHETYPE);
       ALL_TYPES.add(STRING);
 
 
@@ -86,16 +72,16 @@ public class Type extends DeclaredEntity
 
       COMPARABLE_TYPES.add(FLOAT);
       COMPARABLE_TYPES.add(INT);
-      COMPARABLE_TYPES.add(SEQUENCE);
-      COMPARABLE_TYPES.add(LAMBDA);
+      COMPARABLE_TYPES.add(SequenceType.ARCHETYPE);
+      COMPARABLE_TYPES.add(LambdaType.ARCHETYPE);
       COMPARABLE_TYPES.add(STRING);
       COMPARABLE_TYPES.add(BOOL);
-      COMPARABLE_TYPES.add(PTR);
+      COMPARABLE_TYPES.add(PointerType.ARCHETYPE);
 
       COLLECTION_TYPES = new HashSet<Type>();
 
-      COLLECTION_TYPES.add(SET);
-      COLLECTION_TYPES.add(LIST);
+      COLLECTION_TYPES.add(CollectionType.SET_ARCHETYPE);
+      COLLECTION_TYPES.add(CollectionType.LIST_ARCHETYPE);
    }
 
    public static Type value_on_missing ()
@@ -109,37 +95,22 @@ public class Type extends DeclaredEntity
       return "Type";
    }
 
+   public static List<Type> generate_default_parameters (final int i)
+   {
+      return Collections.nCopies(i, Type.ANY);
+   }
 
    /***************************************************************************/
    /**** MEMBERS **************************************************************/
    /***************************************************************************/
    protected final Type true_type;
    protected final Type parent;
+   protected final List<Type> parameters;
 
    /***************************************************************************/
    /**** PUBLIC ***************************************************************/
    /***************************************************************************/
 
-   /**** Constructors *********************************************************/
-   public static Type build
-   (
-      final Origin origin,
-      final Type parent,
-      final String name
-   )
-   throws InvalidTypeException
-   {
-      if (!COMPARABLE_TYPES.contains(parent.get_act_as_type()))
-      {
-         ErrorManager.handle
-         (
-            new InvalidTypeException(origin, parent, COMPARABLE_TYPES)
-         );
-      }
-
-      return new Type(origin, parent, name);
-   }
-
    /**** Accessors ************************************************************/
    public Type get_base_type ()
    {
@@ -148,7 +119,7 @@ public class Type extends DeclaredEntity
 
    public Type get_act_as_type ()
    {
-      return true_type;
+      return get_base_type();
    }
 
    public boolean is_base_type ()
@@ -156,6 +127,11 @@ public class Type extends DeclaredEntity
       return (parent == null);
    }
 
+   public List<Type> get_parameters ()
+   {
+      return parameters;
+   }
+
    public Type try_merging_with (final Type t)
    {
       if (t.get_base_type() != get_base_type())
@@ -263,9 +239,31 @@ public class Type extends DeclaredEntity
 
       sb.append(name);
 
+      for (final Type t: parameters)
+      {
+         sb.append("<");
+         sb.append(t.toString());
+         sb.append(">");
+      }
+
       return sb.toString();
    }
 
+   public Type generate_variant
+   (
+      final Origin origin,
+      final List<Type> parameters
+   )
+   throws Throwable
+   {
+      if (this.parameters.size() != parameters.size())
+      {
+         // TODO: error;
+      }
+
+      return new Type(origin, get_base_type(), name, parameters);
+   }
+
    /***************************************************************************/
    /**** PROTECTED ************************************************************/
    /***************************************************************************/
@@ -273,6 +271,29 @@ public class Type extends DeclaredEntity
    (
       final Origin origin,
       final Type parent,
+      final String name,
+      final List<Type> parameters
+   )
+   {
+      super(origin, name);
+
+      if (parent == null)
+      {
+         true_type = this;
+      }
+      else
+      {
+         true_type = parent.true_type;
+      }
+
+      this.parent = parent;
+      this.parameters = parameters;
+   }
+
+   protected Type
+   (
+      final Origin origin,
+      final Type parent,
       final String name
    )
    {
@@ -288,6 +309,7 @@ public class Type extends DeclaredEntity
       }
 
       this.parent = parent;
+      this.parameters = generate_default_parameters(0);
    }
 
    protected boolean this_or_parent_equals (final Type t)
diff --git a/src/core/src/tonkadur/fate/v1/parser/FateParser.g4 b/src/core/src/tonkadur/fate/v1/parser/FateParser.g4
index a8a5d06..9400c8b 100644
--- a/src/core/src/tonkadur/fate/v1/parser/FateParser.g4
+++ b/src/core/src/tonkadur/fate/v1/parser/FateParser.g4
@@ -206,9 +206,12 @@ first_level_instruction
       PARSER.get_world().extra_computations().add(extra_computation);
    }
 
-   | DECLARE_EXTRA_TYPE_KW identifier maybe_type_list WS* R_PAREN
+   | DECLARE_EXTRA_TYPE_KW identifier WS+ argc=WORD WS+ comp=WORD WS* R_PAREN
    {
+      final Type new_type;
       final Origin start_origin;
+      int arg_count;
+      boolean is_comparable;
 
       start_origin =
          PARSER.get_origin_at
@@ -217,15 +220,48 @@ first_level_instruction
             ($DECLARE_EXTRA_TYPE_KW.getCharPositionInLine())
          );
 
-      PARSER.get_world().types().add
-      (
+      try
+      {
+         arg_count = Integer.parseInt($argc.text);
+
+         if (arg_count < 0)
+         {
+            // TODO: show error.
+         }
+      }
+      catch (final Exception e)
+      {
+         arg_count = 0;
+         // TODO: show error.
+         throw e;
+      }
+
+      try
+      {
+         is_comparable = Boolean.parseBoolean($comp.text);
+      }
+      catch (final Exception e)
+      {
+         is_comparable = false;
+         // TODO: show error.
+         throw e;
+      }
+
+      new_type =
          new ExtraType
          (
             start_origin,
+            null,
             ($identifier.result),
-            ($maybe_type_list.result)
-         )
-      );
+            Type.generate_default_parameters(arg_count)
+         );
+
+      PARSER.get_world().types().add(new_type);
+
+      if (is_comparable)
+      {
+         Type.COMPARABLE_TYPES.add(new_type);
+      }
    }
 
    | DECLARE_EVENT_TYPE_KW identifier maybe_type_list WS* R_PAREN
@@ -385,7 +421,7 @@ first_level_instruction
 
    | REQUIRE_EXTENSION_KW WORD WS* R_PAREN
    {
-      WORLD.add_required_extension(($WORD.text));
+      PARSER.get_world().add_required_extension(($WORD.text));
 
       /* TODO: error report if extension not explicitly enabled. */
    }
@@ -440,7 +476,11 @@ first_level_instruction
             ($WORD.getCharPositionInLine())
          );
 
-      instr = WORLD.extension_first_level_instructions().get(($WORD.text));
+      instr =
+         PARSER.get_world().extension_first_level_instructions().get
+         (
+            ($WORD.text)
+         );
 
       if (instr == null)
       {
@@ -1544,24 +1584,63 @@ returns [Type result]
             ),
             ($WORD.text)
          );
+
+      if ($result.get_parameters().size() != 0)
+      {
+         // TODO: throw error.
+      }
    }
 
-   | L_PAREN identifier WS+ type_list WS* R_PAREN
+   | LAMBDA_KW type WS* L_PAREN maybe_type_list R_PAREN WS* R_PAREN
    {
       final Type t;
 
       t =
-         PARSER.get_world().types().get
+         new LambdaType
          (
             PARSER.get_origin_at
             (
-               ($L_PAREN.getLine()),
-               ($L_PAREN.getCharPositionInLine())
+               ($LAMBDA_KW.getLine()),
+               ($LAMBDA_KW.getCharPositionInLine())
             ),
-            ($identifier.result)
+            ($type.result),
+            "autogenerated lambda type",
+            ($maybe_type_list.result)
+         );
+   }
+
+   | SEQUENCE_KW maybe_type_list R_PAREN
+   {
+      final Type t;
+
+      t =
+         new SequenceType
+         (
+            PARSER.get_origin_at
+            (
+               ($SEQUENCE_KW.getLine()),
+               ($SEQUENCE_KW.getCharPositionInLine())
+            ),
+            "autogenerated sequence type",
+            ($maybe_type_list.result)
+         );
+   }
+
+   | L_PAREN identifier WS+ type_list WS* R_PAREN
+   {
+      final Origin origin;
+      final Type t;
+
+      origin =
+         PARSER.get_origin_at
+         (
+            ($L_PAREN.getLine()),
+            ($L_PAREN.getCharPositionInLine())
          );
 
-      $result = t.build($type_list.result);
+      t = PARSER.get_world().types().get(origin, ($identifier.result));
+
+      $result = t.generate_variant(origin, $type_list.result);
    }
 ;
 catch [final Throwable e]
diff --git a/src/core/src/tonkadur/fate/v1/parser/ParserData.java b/src/core/src/tonkadur/fate/v1/parser/ParserData.java
index 45ef985..ce73193 100644
--- a/src/core/src/tonkadur/fate/v1/parser/ParserData.java
+++ b/src/core/src/tonkadur/fate/v1/parser/ParserData.java
@@ -18,6 +18,7 @@ import org.antlr.v4.runtime.misc.ParseCancellationException;
 
 import tonkadur.parser.Context;
 import tonkadur.parser.Origin;
+import tonkadur.parser.ParsingError;
 
 import tonkadur.error.ErrorManager;
 
@@ -202,7 +203,7 @@ public class ParserData
    }
 
    public void add_file_content (final Origin origin, final String filename)
-   throws IOException
+   throws IOException, ParsingError
    {
       final CommonTokenStream tokens;
       final FateLexer lexer;