Type-check components of val node

5 files changed, 48 insertions, 3 deletions

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 f57fd61c..8dfbd7cb 100644
--- a/src/main/java/org/shedlang/compiler/ast/typed/TypedFunctionStatementNode.java
+++ b/src/main/java/org/shedlang/compiler/ast/typed/TypedFunctionStatementNode.java
@@ -1,4 +1,4 @@
 package org.shedlang.compiler.ast.typed;
 
-public sealed interface TypedFunctionStatementNode extends TypedNode permits TypedExpressionStatementNode {
+public sealed interface TypedFunctionStatementNode extends TypedNode permits TypedExpressionStatementNode, TypedValNode {
 }
diff --git a/src/main/java/org/shedlang/compiler/ast/typed/TypedTargetNode.java b/src/main/java/org/shedlang/compiler/ast/typed/TypedTargetNode.java
new file mode 100644
index 00000000..7af7203f
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/ast/typed/TypedTargetNode.java
@@ -0,0 +1,7 @@
+package org.shedlang.compiler.ast.typed;
+
+import org.shedlang.compiler.sources.Source;
+
+public sealed interface TypedTargetNode extends TypedNode {
+    record Variable(String name, Source source) implements TypedTargetNode {}
+}
diff --git a/src/main/java/org/shedlang/compiler/ast/typed/TypedValNode.java b/src/main/java/org/shedlang/compiler/ast/typed/TypedValNode.java
new file mode 100644
index 00000000..e543312f
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/ast/typed/TypedValNode.java
@@ -0,0 +1,10 @@
+package org.shedlang.compiler.ast.typed;
+
+import org.shedlang.compiler.sources.Source;
+
+public record TypedValNode(
+    TypedTargetNode target,
+    TypedExpressionNode expression,
+    Source source
+) implements TypedFunctionStatementNode {
+}
diff --git a/src/main/java/org/shedlang/compiler/stackir/StackCompiler.java b/src/main/java/org/shedlang/compiler/stackir/StackCompiler.java
index 2301510d..7ff1338a 100644
--- a/src/main/java/org/shedlang/compiler/stackir/StackCompiler.java
+++ b/src/main/java/org/shedlang/compiler/stackir/StackCompiler.java
@@ -96,7 +96,10 @@ public class StackCompiler {
     public static PVector<Instruction> compileFunctionStatement(TypedFunctionStatementNode node) {
         return switch (node) {
             case TypedExpressionStatementNode expressionStatement ->
-                compileExpressionStatement(expressionStatement);  
+                compileExpressionStatement(expressionStatement);
+
+            case TypedValNode val ->
+                throw new UnsupportedOperationException("TODO");
         };
     }
 
diff --git a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
index c5cb4470..228f1fa0 100644
--- a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
+++ b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
@@ -261,7 +261,7 @@ public class TypeChecker {
                 typeCheckExpressionStatement(expressionStatement, context);
 
             case UntypedValNode val ->
-                throw new UnsupportedOperationException("TODO");
+                typeCheckVal(val, context);
         };
     }
 
@@ -394,4 +394,29 @@ public class TypeChecker {
             untyped.source()
         );
     }
+
+    private static TypeCheckerResult<TypedFunctionStatementNode> typeCheckVal(
+        UntypedValNode val,
+        TypeCheckerContext context
+    ) {
+        var expressionResult = typeCheckExpression(val.expression(), context);
+        var expression = expressionResult.value();
+        context = expressionResult.context();
+        
+        var targetResult = typeCheckTarget(val.target(), context);
+        var target = targetResult.value();
+        context = targetResult.context();
+        
+        return context.toResult(new TypedValNode(target, expression, val.source()));
+    }
+
+    private static TypeCheckerResult<TypedTargetNode> typeCheckTarget(
+        UntypedTargetNode target,
+        TypeCheckerContext context
+    ) {
+        return switch (target) {
+            case UntypedTargetNode.Variable variable ->
+                context.toResult(new TypedTargetNode.Variable(variable.name(), target.source()));
+        };
+    }
 }