Type check struct fields

6 files changed, 110 insertions, 10 deletions

diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/HobgoblinCompiler.java b/src/main/java/org/zwobble/hobgoblin/compiler/HobgoblinCompiler.java
index 4f56fb1..d9f7d21 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/HobgoblinCompiler.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/HobgoblinCompiler.java
@@ -4,6 +4,7 @@ import org.zwobble.hobgoblin.compiler.parser.Parser;
 import org.zwobble.hobgoblin.compiler.typechecker.TypeChecker;
 import org.zwobble.hobgoblin.compiler.typechecker.TypeCheckerGlobalContext;
 import org.zwobble.hobgoblin.compiler.types.NamespaceName;
+import org.zwobble.hobgoblin.compiler.types.ScalarType;
 import org.zwobble.sourcetext.SourceText;
 
 import java.io.IOException;
@@ -29,6 +30,8 @@ public class HobgoblinCompiler {
             var untypedNamespaceNode = Parser.parseNamespace(sourceText, namespaceName);
 
             var typeCheckerContext = TypeCheckerGlobalContext.initial();
+            typeCheckerContext.addBuiltinScalarType(new ScalarType("Int32"));
+
             var typedNamespaceNode = TypeChecker.typeCheckNamespace(untypedNamespaceNode, typeCheckerContext);
         }
     }
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/TypeChecker.java b/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/TypeChecker.java
index b8bdd7f..d9a37e2 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/TypeChecker.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/TypeChecker.java
@@ -2,13 +2,9 @@ package org.zwobble.hobgoblin.compiler.typechecker;
 
 import org.zwobble.hobgoblin.compiler.ast.typed.*;
 import org.zwobble.hobgoblin.compiler.ast.untyped.*;
-import org.zwobble.hobgoblin.compiler.types.StructType;
-import org.zwobble.hobgoblin.compiler.types.TypeLevelValue;
-import org.zwobble.hobgoblin.compiler.types.TypeLevelValueType;
-import org.zwobble.hobgoblin.compiler.types.TypeSet;
+import org.zwobble.hobgoblin.compiler.types.*;
 
 import java.util.ArrayList;
-import java.util.List;
 
 public class TypeChecker {
     private TypeChecker() {
@@ -49,13 +45,36 @@ public class TypeChecker {
     ) {
         var structType = new StructType(context.namespaceName(), untyped.name());
 
+        var typedFields = new ArrayList<TypedStructFieldDefinitionNode>();
+        for (var untypedField : untyped.fields()) {
+            var typedField = new TypedStructFieldDefinitionNode(
+                untypedField.name(),
+                typeCheckMetaType(untypedField.type(), context),
+                untyped.source()
+            );
+            typedFields.add(typedField);
+        }
+
         return new TypedStructDefinitionNode(
             structType,
-            List.of(),
+            typedFields,
             untyped.source()
         );
     }
 
+    private static TypedTypeLevelExpressionNode<Type> typeCheckMetaType(
+        UntypedTypeLevelExpressionNode untyped,
+        TypeCheckerNamespaceContext context
+    ) {
+        var typed = typeCheckTypeLevelExpression(untyped, context);
+        if (typed.value() instanceof Type) {
+            return (TypedTypeLevelExpressionNode<Type>) typed;
+        } else {
+            // TODO: better error
+            throw new RuntimeException("not a metatype");
+        }
+    }
+
     static TypedTypeLevelExpressionNode<? extends TypeLevelValue> typeCheckTypeLevelExpression(
         UntypedTypeLevelExpressionNode untyped,
         TypeCheckerNamespaceContext context
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerGlobalContext.java b/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerGlobalContext.java
index 3915767..849da2f 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerGlobalContext.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerGlobalContext.java
@@ -1,8 +1,16 @@
 package org.zwobble.hobgoblin.compiler.typechecker;
 
 import org.zwobble.hobgoblin.compiler.types.NamespaceName;
+import org.zwobble.hobgoblin.compiler.types.ScalarType;
+import org.zwobble.hobgoblin.compiler.types.Type;
+import org.zwobble.hobgoblin.compiler.types.TypeLevelValueType;
+
+import java.util.HashMap;
+import java.util.Map;
 
 public class TypeCheckerGlobalContext {
+    private final Map<String, Type> builtins = new HashMap<>();
+
     public static TypeCheckerGlobalContext initial() {
         return new TypeCheckerGlobalContext();
     }
@@ -10,7 +18,11 @@ public class TypeCheckerGlobalContext {
     private TypeCheckerGlobalContext() {
     }
 
+    public void addBuiltinScalarType(ScalarType type) {
+        this.builtins.put(type.name(), new TypeLevelValueType(type));
+    }
+
     public TypeCheckerNamespaceContext enterNamespace(NamespaceName namespaceName) {
-        return TypeCheckerNamespaceContext.initial(namespaceName);
+        return TypeCheckerNamespaceContext.initial(namespaceName, this.builtins);
     }
 }
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerNamespaceContext.java b/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerNamespaceContext.java
index c1a23fd..353209b 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerNamespaceContext.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerNamespaceContext.java
@@ -3,13 +3,22 @@ package org.zwobble.hobgoblin.compiler.typechecker;
 import org.zwobble.hobgoblin.compiler.types.NamespaceName;
 import org.zwobble.hobgoblin.compiler.types.Type;
 
-import java.util.HashMap;
 import java.util.Map;
 import java.util.Optional;
+import java.util.stream.Collectors;
 
 public class TypeCheckerNamespaceContext {
-    public static TypeCheckerNamespaceContext initial(NamespaceName namespaceName) {
-        return new TypeCheckerNamespaceContext(namespaceName, new HashMap<>());
+    public static TypeCheckerNamespaceContext initial(
+        NamespaceName namespaceName,
+        Map<String, Type> builtins
+    ) {
+        var variables = builtins.entrySet().stream()
+            .collect(Collectors.toMap(
+                entry -> entry.getKey(),
+                entry -> Variable.defined(entry.getValue())
+            ));
+
+        return new TypeCheckerNamespaceContext(namespaceName, variables);
     }
 
     private final NamespaceName namespaceName;
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/Variable.java b/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/Variable.java
index 1d3a4b6..e80283f 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/Variable.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/typechecker/Variable.java
@@ -3,6 +3,10 @@ package org.zwobble.hobgoblin.compiler.typechecker;
 import org.zwobble.hobgoblin.compiler.types.Type;
 
 public sealed interface Variable {
+    public static Variable defined(Type type) {
+        return new Defined(type);
+    }
+
     record Declared() implements Variable {
     }
 
diff --git a/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerStructDefinitionTests.java b/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerStructDefinitionTests.java
index b6fddba..f13731f 100644
--- a/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerStructDefinitionTests.java
+++ b/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerStructDefinitionTests.java
@@ -2,10 +2,16 @@ package org.zwobble.hobgoblin.compiler.typechecker;
 
 import org.junit.jupiter.api.Test;
 import org.zwobble.hobgoblin.compiler.ast.typed.TypedStructDefinitionNode;
+import org.zwobble.hobgoblin.compiler.ast.typed.TypedStructFieldDefinitionNode;
+import org.zwobble.hobgoblin.compiler.ast.typed.TypedTypeLevelExpressionNode;
+import org.zwobble.hobgoblin.compiler.ast.untyped.UntypedArb;
 import org.zwobble.hobgoblin.compiler.ast.untyped.UntypedStructDefinitionNode;
+import org.zwobble.hobgoblin.compiler.ast.untyped.UntypedStructFieldDefinitionNode;
 import org.zwobble.hobgoblin.compiler.sources.NullSource;
 import org.zwobble.hobgoblin.compiler.types.NamespaceName;
+import org.zwobble.hobgoblin.compiler.types.ScalarType;
 import org.zwobble.hobgoblin.compiler.types.StructType;
+import org.zwobble.hobgoblin.compiler.types.TypeLevelValueType;
 
 import java.util.List;
 
@@ -33,4 +39,51 @@ public class TypeCheckerStructDefinitionTests {
             )
         ));
     }
+
+    @Test
+    public void fieldsAreTypeChecked() {
+        var int32Type = new ScalarType("Int32");
+        var int64Type = new ScalarType("Int64");
+        var untyped = new UntypedStructDefinitionNode(
+            "X",
+            List.of(
+                new UntypedStructFieldDefinitionNode("a", UntypedArb.typeLevelReference("Int32"), NullSource.INSTANCE),
+                new UntypedStructFieldDefinitionNode("b", UntypedArb.typeLevelReference("Int64"), NullSource.INSTANCE)
+            ),
+            NullSource.INSTANCE
+        );
+        var context = TypeCheckerContextArb.namespaceContext(NamespaceName.of("a", "b"));
+        context.declare(int32Type.name());
+        context.define(int32Type.name(), new TypeLevelValueType(int32Type));
+        context.declare(int64Type.name());
+        context.define(int64Type.name(), new TypeLevelValueType(int64Type));
+
+        var typed = TypeChecker.typeCheckNamespaceStatement(untyped, context);
+
+        assertThat(typed, instanceOf(
+            TypedStructDefinitionNode.class,
+            has(
+                "fields",
+                TypedStructDefinitionNode::fields,
+                isSequence(
+                    allOf(
+                        has("name", TypedStructFieldDefinitionNode::name, equalTo("a")),
+                        has("type", TypedStructFieldDefinitionNode::type, has(
+                            "value",
+                            TypedTypeLevelExpressionNode::value,
+                            equalTo(int32Type)
+                        ))
+                    ),
+                    allOf(
+                        has("name", TypedStructFieldDefinitionNode::name, equalTo("b")),
+                        has("type", TypedStructFieldDefinitionNode::type, has(
+                            "value",
+                            TypedTypeLevelExpressionNode::value,
+                            equalTo(int64Type)
+                        ))
+                    )
+                )
+            )
+        ));
+    }
 }