Declare types ahead of defining them

2 files changed, 95 insertions, 2 deletions

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 f13731f..aec039b 100644
--- a/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerStructDefinitionTests.java
+++ b/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerStructDefinitionTests.java
@@ -1,10 +1,12 @@
 package org.zwobble.hobgoblin.compiler.typechecker;
 
 import org.junit.jupiter.api.Test;
+import org.zwobble.hobgoblin.compiler.ast.typed.TypedNamespaceNode;
 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.UntypedNamespaceNode;
 import org.zwobble.hobgoblin.compiler.ast.untyped.UntypedStructDefinitionNode;
 import org.zwobble.hobgoblin.compiler.ast.untyped.UntypedStructFieldDefinitionNode;
 import org.zwobble.hobgoblin.compiler.sources.NullSource;
@@ -15,6 +17,7 @@ import org.zwobble.hobgoblin.compiler.types.TypeLevelValueType;
 
 import java.util.List;
 
+import static org.zwobble.hobgoblin.compiler.typechecker.TypeCheckerTesting.typeCheckNamespaceStatement;
 import static org.zwobble.precisely.AssertThat.assertThat;
 import static org.zwobble.precisely.Matchers.*;
 
@@ -28,7 +31,7 @@ public class TypeCheckerStructDefinitionTests {
         );
         var context = TypeCheckerContextArb.namespaceContext(NamespaceName.of("a", "b"));
 
-        var typed = TypeChecker.typeCheckNamespaceStatement(untyped, context);
+        var typed = typeCheckNamespaceStatement(untyped, context);
 
         assertThat(typed, instanceOf(
             TypedStructDefinitionNode.class,
@@ -58,7 +61,7 @@ public class TypeCheckerStructDefinitionTests {
         context.declare(int64Type.name());
         context.define(int64Type.name(), new TypeLevelValueType(int64Type));
 
-        var typed = TypeChecker.typeCheckNamespaceStatement(untyped, context);
+        var typed = typeCheckNamespaceStatement(untyped, context);
 
         assertThat(typed, instanceOf(
             TypedStructDefinitionNode.class,
@@ -86,4 +89,77 @@ public class TypeCheckerStructDefinitionTests {
             )
         ));
     }
+
+    @Test
+    public void structCanUseTypeDefinedLater() {
+        var int32Type = new ScalarType("Int32");
+        var namespaceName = NamespaceName.of("a", "b");
+        var untyped = new UntypedNamespaceNode(
+            namespaceName,
+            List.of(
+                new UntypedStructDefinitionNode(
+                    "X",
+                    List.of(
+                        new UntypedStructFieldDefinitionNode("value", UntypedArb.typeLevelReference("Y"), NullSource.INSTANCE)
+                    ),
+                    NullSource.INSTANCE
+                ),
+                new UntypedStructDefinitionNode(
+                    "Y",
+                    List.of(
+                        new UntypedStructFieldDefinitionNode("value", UntypedArb.typeLevelReference("Int32"), NullSource.INSTANCE)
+                    ),
+                    NullSource.INSTANCE
+                )
+            ),
+            NullSource.INSTANCE
+        );
+        var context = TypeCheckerContextArb.globalContext();
+        context.addBuiltinScalarType(int32Type);
+
+        var typed = TypeChecker.typeCheckNamespace(untyped, context);
+
+        assertThat(typed, has(
+            "body",
+            TypedNamespaceNode::body,
+            isSequence(
+                instanceOf(
+                    TypedStructDefinitionNode.class,
+                    has("name", TypedStructDefinitionNode::name, equalTo("X")),
+                    has(
+                        "fields",
+                        TypedStructDefinitionNode::fields,
+                        isSequence(
+                            allOf(
+                                has("name", TypedStructFieldDefinitionNode::name, equalTo("value")),
+                                has("type", TypedStructFieldDefinitionNode::type, has(
+                                    "value",
+                                    TypedTypeLevelExpressionNode::value,
+                                    equalTo(new StructType(namespaceName, "Y"))
+                                ))
+                            )
+                        )
+                    )
+                ),
+                instanceOf(
+                    TypedStructDefinitionNode.class,
+                    has("name", TypedStructDefinitionNode::name, equalTo("Y")),
+                    has(
+                        "fields",
+                        TypedStructDefinitionNode::fields,
+                        isSequence(
+                            allOf(
+                                has("name", TypedStructFieldDefinitionNode::name, equalTo("value")),
+                                has("type", TypedStructFieldDefinitionNode::type, has(
+                                    "value",
+                                    TypedTypeLevelExpressionNode::value,
+                                    equalTo(int32Type)
+                                ))
+                            )
+                        )
+                    )
+                )
+            )
+        ));
+    }
 }
diff --git a/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerTesting.java b/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerTesting.java
new file mode 100644
index 0000000..b0c21ec
--- /dev/null
+++ b/src/test/java/org/zwobble/hobgoblin/compiler/typechecker/TypeCheckerTesting.java
@@ -0,0 +1,17 @@
+package org.zwobble.hobgoblin.compiler.typechecker;
+
+import org.zwobble.hobgoblin.compiler.ast.typed.TypedNamespaceStatementNode;
+import org.zwobble.hobgoblin.compiler.ast.untyped.UntypedNamespaceStatementNode;
+
+public class TypeCheckerTesting {
+    private TypeCheckerTesting() {
+    }
+
+    public static TypedNamespaceStatementNode typeCheckNamespaceStatement(
+        UntypedNamespaceStatementNode untyped,
+        TypeCheckerNamespaceContext context
+    ) {
+        TypeChecker.declareNamespaceStatement(untyped, context);
+        return TypeChecker.defineNamespaceStatement(untyped, context);
+    }
+}