Improve generic support in the interpreter

4 files changed, 35 insertions, 17 deletions

diff --git a/src/main/java/org/zwobble/couscous/interpreter/Evaluator.java b/src/main/java/org/zwobble/couscous/interpreter/Evaluator.java
index bbc41d1..4c2a8c3 100644
--- a/src/main/java/org/zwobble/couscous/interpreter/Evaluator.java
+++ b/src/main/java/org/zwobble/couscous/interpreter/Evaluator.java
@@ -52,7 +52,7 @@ public class Evaluator implements ExpressionNodeMapper<InterpreterValue> {
     public InterpreterValue visit(ThisReferenceNode reference) {
         InterpreterValue thisValue = environment.getThis().get();
         // TODO: add a test for this
-        InterpreterTypes.checkIsInstance(reference.getType(), thisValue);
+        //InterpreterTypes.checkIsInstance(reference.getType(), thisValue);
         return thisValue;
     }
 
@@ -102,7 +102,7 @@ public class Evaluator implements ExpressionNodeMapper<InterpreterValue> {
         MethodSignature signature = methodCall.signature();
 
         return evalReceiver(methodCall.getReceiver())
-            .callMethod(environment, signature, new Arguments(list(), arguments));
+            .callMethod(environment, signature.generic(), new Arguments(list(), arguments));
     }
     
     @Override
diff --git a/src/main/java/org/zwobble/couscous/interpreter/types/ParameterizedInterpreterType.java b/src/main/java/org/zwobble/couscous/interpreter/types/ParameterizedInterpreterType.java
index 52ec6e1..0d82e6c 100644
--- a/src/main/java/org/zwobble/couscous/interpreter/types/ParameterizedInterpreterType.java
+++ b/src/main/java/org/zwobble/couscous/interpreter/types/ParameterizedInterpreterType.java
@@ -6,27 +6,33 @@ import org.zwobble.couscous.ast.StatementNode;
 import org.zwobble.couscous.interpreter.Arguments;
 import org.zwobble.couscous.interpreter.Environment;
 import org.zwobble.couscous.interpreter.values.InterpreterValue;
-import org.zwobble.couscous.types.ScalarType;
+import org.zwobble.couscous.types.ParameterizedType;
 import org.zwobble.couscous.types.Type;
+import org.zwobble.couscous.types.TypeParameter;
+import org.zwobble.couscous.types.Types;
+import org.zwobble.couscous.util.ExtraIterables;
 
 import java.util.List;
+import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
+import java.util.stream.Collectors;
 
 import static org.zwobble.couscous.types.ParameterizedType.parameterizedType;
+import static org.zwobble.couscous.util.ExtraMaps.toMap;
 
 public class ParameterizedInterpreterType implements InterpreterType {
-    private final InterpreterType rawType;
+    private final InterpreterType genericType;
     private final List<Type> parameters;
 
-    public ParameterizedInterpreterType(InterpreterType rawType, List<Type> parameters) {
-        this.rawType = rawType;
+    public ParameterizedInterpreterType(InterpreterType genericType, List<Type> parameters) {
+        this.genericType = genericType;
         this.parameters = parameters;
     }
 
     @Override
     public Type getType() {
-        return parameterizedType((ScalarType) rawType.getType(), parameters);
+        return parameterizedType(((ParameterizedType) genericType.getType()).getRawType(), parameters);
     }
 
     // TODO: implement the other methods properly.
@@ -36,12 +42,18 @@ public class ParameterizedInterpreterType implements InterpreterType {
 
     @Override
     public Set<Type> getSuperTypes() {
-        throw new UnsupportedOperationException();
+        Map<TypeParameter, Type> replacements = toMap(
+            ExtraIterables.cast(TypeParameter.class, ((ParameterizedType) genericType.getType()).getParameters()),
+            parameters);
+        return genericType.getSuperTypes()
+            .stream()
+            .map(type -> Types.substitute(type, replacements))
+            .collect(Collectors.toSet());
     }
 
     @Override
     public Optional<FieldDeclarationNode> getField(String fieldName) {
-        throw new UnsupportedOperationException();
+        return genericType.getField(fieldName);
     }
 
     @Override
@@ -56,7 +68,7 @@ public class ParameterizedInterpreterType implements InterpreterType {
 
     @Override
     public InterpreterValue callMethod(Environment environment, InterpreterValue value, MethodSignature signature, Arguments arguments) {
-        throw new UnsupportedOperationException();
+        return genericType.callMethod(environment, value, signature.generic(), arguments);
     }
 
     @Override
diff --git a/src/main/java/org/zwobble/couscous/interpreter/types/UserDefinedInterpreterType.java b/src/main/java/org/zwobble/couscous/interpreter/types/UserDefinedInterpreterType.java
index 3b056f1..c26fb32 100644
--- a/src/main/java/org/zwobble/couscous/interpreter/types/UserDefinedInterpreterType.java
+++ b/src/main/java/org/zwobble/couscous/interpreter/types/UserDefinedInterpreterType.java
@@ -1,15 +1,15 @@
 package org.zwobble.couscous.interpreter.types;
 
 import org.zwobble.couscous.ast.*;
+import org.zwobble.couscous.interpreter.Arguments;
 import org.zwobble.couscous.interpreter.Environment;
 import org.zwobble.couscous.interpreter.Executor;
 import org.zwobble.couscous.interpreter.InterpreterTypes;
-import org.zwobble.couscous.interpreter.Arguments;
 import org.zwobble.couscous.interpreter.errors.NoSuchMethod;
 import org.zwobble.couscous.interpreter.errors.WrongNumberOfArguments;
 import org.zwobble.couscous.interpreter.values.InterpreterValue;
-import org.zwobble.couscous.types.ScalarType;
 import org.zwobble.couscous.types.Type;
+import org.zwobble.couscous.types.TypeParameter;
 
 import java.util.List;
 import java.util.Map;
@@ -17,6 +17,7 @@ import java.util.Optional;
 import java.util.Set;
 
 import static com.google.common.collect.Iterables.filter;
+import static org.zwobble.couscous.types.ParameterizedType.parameterizedType;
 import static org.zwobble.couscous.util.Casts.tryCast;
 import static org.zwobble.couscous.util.ExtraLists.eagerMap;
 import static org.zwobble.couscous.util.ExtraLists.list;
@@ -35,12 +36,17 @@ public class UserDefinedInterpreterType implements InterpreterType {
             .orElse(map());
         this.methods = toMapWithKeys(
             filter(type.getMethods(), method -> !method.isAbstract()),
-            method -> method.signature());
+            method -> method.signature().generic());
     }
 
     @Override
-    public ScalarType getType() {
-        return type.getName();
+    public Type getType() {
+        List<Type> parameters = eagerMap(
+            type.getTypeParameters(),
+            parameter -> new TypeParameter(type.getName(), parameter.getName()));
+        return parameters.isEmpty()
+            ? type.getName()
+            : parameterizedType(type.getName(), parameters);
     }
 
     @Override
diff --git a/src/main/java/org/zwobble/couscous/interpreter/values/InterpreterFields.java b/src/main/java/org/zwobble/couscous/interpreter/values/InterpreterFields.java
index 50ed24f..b0b7992 100644
--- a/src/main/java/org/zwobble/couscous/interpreter/values/InterpreterFields.java
+++ b/src/main/java/org/zwobble/couscous/interpreter/values/InterpreterFields.java
@@ -1,7 +1,6 @@
 package org.zwobble.couscous.interpreter.values;
 
 import org.zwobble.couscous.ast.FieldDeclarationNode;
-import org.zwobble.couscous.interpreter.InterpreterTypes;
 import org.zwobble.couscous.interpreter.errors.NoSuchField;
 import org.zwobble.couscous.interpreter.errors.UnboundField;
 import org.zwobble.couscous.interpreter.types.InterpreterType;
@@ -39,7 +38,8 @@ public class InterpreterFields {
 
     public void setField(String fieldName, InterpreterValue value) {
         FieldDeclarationNode field = getFieldDefinition(fieldName);
-        InterpreterTypes.checkIsInstance(field.getType(), value);
+        // TODO: re-enable this
+        //InterpreterTypes.checkIsInstance(field.getType(), value);
         fields.put(fieldName, value);
     }