From 72ce4e94a08baf5d722582e2914bb2074ef7d1a7 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Sat, 2 Dec 2023 23:55:03 +0000
Subject: Type check break statements

---
 .../compiler/ast/typed/TypedBreakNode.java         | 13 ++++++++++
 .../ast/typed/TypedFunctionStatementNode.java      |  2 +-
 .../org/shedlang/compiler/shid/ShidCodeGen.java    |  3 +++
 .../shedlang/compiler/typechecker/TypeChecker.java | 30 +++++++++++++++++++++-
 ...nnotBreakOutsideOfEffectHandlerMethodError.java | 10 ++++++++
 5 files changed, 56 insertions(+), 2 deletions(-)
 create mode 100644 src/main/java/org/shedlang/compiler/ast/typed/TypedBreakNode.java
 create mode 100644 src/main/java/org/shedlang/compiler/typechecker/errors/CannotBreakOutsideOfEffectHandlerMethodError.java

(limited to 'src/main/java')

diff --git a/src/main/java/org/shedlang/compiler/ast/typed/TypedBreakNode.java b/src/main/java/org/shedlang/compiler/ast/typed/TypedBreakNode.java
new file mode 100644
index 00000000..bc7ea34a
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/ast/typed/TypedBreakNode.java
@@ -0,0 +1,13 @@
+package org.shedlang.compiler.ast.typed;
+
+import org.shedlang.compiler.sources.Source;
+
+public record TypedBreakNode(
+    TypedExpressionNode expression,
+    Source source
+) implements TypedFunctionStatementNode {
+    @Override
+    public TypedFunctionStatementBehaviour behaviour() {
+        return TypedFunctionStatementBehaviour.TERMINATE;
+    }
+}
diff --git a/src/main/java/org/shedlang/compiler/ast/typed/TypedFunctionStatementNode.java b/src/main/java/org/shedlang/compiler/ast/typed/TypedFunctionStatementNode.java
index a79437ec..82c90eea 100644
--- a/src/main/java/org/shedlang/compiler/ast/typed/TypedFunctionStatementNode.java
+++ b/src/main/java/org/shedlang/compiler/ast/typed/TypedFunctionStatementNode.java
@@ -1,5 +1,5 @@
 package org.shedlang.compiler.ast.typed;
 
-public sealed interface TypedFunctionStatementNode extends TypedNode permits TypedAssignNode, TypedBlockReturnNode, TypedExpressionStatementNode, TypedFunctionReturnNode, TypedResumeNode, TypedWhileNode {
+public sealed interface TypedFunctionStatementNode extends TypedNode permits TypedAssignNode, TypedBlockReturnNode, TypedBreakNode, TypedExpressionStatementNode, TypedFunctionReturnNode, TypedResumeNode, TypedWhileNode {
     TypedFunctionStatementBehaviour behaviour();
 }
diff --git a/src/main/java/org/shedlang/compiler/shid/ShidCodeGen.java b/src/main/java/org/shedlang/compiler/shid/ShidCodeGen.java
index 8c930b29..5ed3ffdb 100644
--- a/src/main/java/org/shedlang/compiler/shid/ShidCodeGen.java
+++ b/src/main/java/org/shedlang/compiler/shid/ShidCodeGen.java
@@ -336,6 +336,9 @@ public class ShidCodeGen {
             case TypedBlockReturnNode blockReturn ->
                 compileBlockReturn(blockReturn, context);
 
+            case TypedBreakNode break_ ->
+                throw new UnsupportedOperationException("TODO");
+
             case TypedExpressionStatementNode expressionStatement ->
                 compileExpressionStatement(expressionStatement, context);
 
diff --git a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
index e7052ba3..ae91c3d0 100644
--- a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
+++ b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
@@ -280,7 +280,35 @@ public class TypeChecker {
         UntypedBreakNode untyped,
         TypeCheckerContext context
     ) {
-        throw new UnsupportedOperationException("TODO");
+        switch (context.returnTypeState()) {
+            case ReturnTypeState.Explicit explicit -> {
+                throw new CannotBreakOutsideOfEffectHandlerMethodError(untyped.source());
+            }
+            case ReturnTypeState.ImplicitUnknown implicitUnknown -> {
+                throw new CannotBreakOutsideOfEffectHandlerMethodError(untyped.source());
+            }
+            case ReturnTypeState.ImplicitLowerBound implicitLowerBound -> {
+                throw new CannotBreakOutsideOfEffectHandlerMethodError(untyped.source());
+            }
+            case ReturnTypeState.NotInFunction notInFunction -> {
+                throw new CannotBreakOutsideOfEffectHandlerMethodError(untyped.source());
+            }
+            case ReturnTypeState.EffectHandler effectHandler -> {
+                var typedExpressionResult = typeCheckExpressionOptional(
+                    untyped.expression(),
+                    Optional.of(effectHandler.resumeType()),
+                    untyped.source(),
+                    context
+                );
+                var typedExpression = typedExpressionResult.value();
+                context = typedExpressionResult.context();
+
+                return context.toResult(new TypedBreakNode(
+                    typedExpression,
+                    untyped.source()
+                ));
+            }
+        }
     }
 
     private static TypeCheckerResult<TypedExpressionNode> typeCheckCall(
diff --git a/src/main/java/org/shedlang/compiler/typechecker/errors/CannotBreakOutsideOfEffectHandlerMethodError.java b/src/main/java/org/shedlang/compiler/typechecker/errors/CannotBreakOutsideOfEffectHandlerMethodError.java
new file mode 100644
index 00000000..3a32ecaa
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/typechecker/errors/CannotBreakOutsideOfEffectHandlerMethodError.java
@@ -0,0 +1,10 @@
+package org.shedlang.compiler.typechecker.errors;
+
+import org.shedlang.compiler.errors.SourceError;
+import org.shedlang.compiler.sources.Source;
+
+public class CannotBreakOutsideOfEffectHandlerMethodError extends SourceError {
+    public CannotBreakOutsideOfEffectHandlerMethodError(Source source) {
+        super("Cannot break outside of effect handler method", source);
+    }
+}
-- 
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