From 186407bd0ecf485f7197027afd04c8c12e5920ce Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Sat, 28 Oct 2023 23:59:56 +0100
Subject: Compile expressions to stack IR

---
 .../ast/typed/TypedFunctionExpressionNode.java     |  9 ---
 .../shedlang/compiler/stackir/StackCompiler.java   | 67 ++++++++++++++++------
 2 files changed, 49 insertions(+), 27 deletions(-)

(limited to 'src/main/java')

diff --git a/src/main/java/org/shedlang/compiler/ast/typed/TypedFunctionExpressionNode.java b/src/main/java/org/shedlang/compiler/ast/typed/TypedFunctionExpressionNode.java
index 0f8ad4bc..1bc46fdb 100644
--- a/src/main/java/org/shedlang/compiler/ast/typed/TypedFunctionExpressionNode.java
+++ b/src/main/java/org/shedlang/compiler/ast/typed/TypedFunctionExpressionNode.java
@@ -44,15 +44,6 @@ public record TypedFunctionExpressionNode(
             );
         }
 
-        public Builder withName(String name) {
-            return new Builder(
-                this.signature,
-                this.freeVariables,
-                this.boundVariableNames,
-                this.body
-            );
-        }
-
         public Builder addPositionalParam(String name, TypedTypeLevelExpressionNode<Type> type) {
             return new Builder(
                 this.signature.addPositionalParam(name, type),
diff --git a/src/main/java/org/shedlang/compiler/stackir/StackCompiler.java b/src/main/java/org/shedlang/compiler/stackir/StackCompiler.java
index bb138c84..8d1468c8 100644
--- a/src/main/java/org/shedlang/compiler/stackir/StackCompiler.java
+++ b/src/main/java/org/shedlang/compiler/stackir/StackCompiler.java
@@ -3,6 +3,7 @@ package org.shedlang.compiler.stackir;
 import org.pcollections.*;
 import org.shedlang.compiler.ShedBuiltins;
 import org.shedlang.compiler.ast.typed.*;
+import org.shedlang.compiler.sources.Source;
 import org.shedlang.compiler.stackir.instructions.*;
 import org.shedlang.compiler.types.*;
 import org.shedlang.compiler.util.Iterables;
@@ -128,7 +129,7 @@ public class StackCompiler {
                 compileFieldAccess(typedFieldAccessNode, context);
 
             case TypedFunctionExpressionNode typedFunctionExpressionNode ->
-                throw new UnsupportedOperationException("TODO");
+                compileFunctionExpression(typedFunctionExpressionNode, context);
 
             case TypedIfNode typedIfNode ->
                 compileIf(typedIfNode, context);
@@ -184,47 +185,50 @@ public class StackCompiler {
         return context;
     }
 
-    private static Context compileFunctionDefinition(
-        TypedFunctionDefinitionNode node,
+    private static Context compileFunction(
+        String name,
+        TypedFunctionSignatureNode signature,
+        TypedFunctionBodyNode body,
+        Source source,
         Context context
     ) {
-        context = context.enterBlock(node.body().boundVariableNames());
+        context = context.enterBlock(body.boundVariableNames());
 
         var c = context;
 
-        var positionalParams = node.signature().params().positional().stream()
+        var positionalParams = signature.params().positional().stream()
             .map(param -> new DefineFunctionInstruction.Param(
                 c.shedVariableToLocal(param.name()),
                 param.source()
             ))
             .toList();
 
-        var namedParams = node.signature().params().named().stream()
+        var namedParams = signature.params().named().stream()
             .map(param -> new DefineFunctionInstruction.Param(
                 c.shedVariableToLocal(param.name()),
                 param.source()
             ))
             .toList();
 
-        context = compileBlockWithYield(node.body().block(), context);
+        context = compileBlockWithYield(body.block(), context);
 
-        switch (node.body().behaviour()) {
+        switch (body.behaviour()) {
             case TypedFunctionStatementBehaviour.BlockReturn blockReturn -> {
-                context = context.addInstruction(new ReturnInstruction(node.source()));
+                context = context.addInstruction(new ReturnInstruction(body.source()));
             }
             case TypedFunctionStatementBehaviour.Continue continue_ -> {
-                context = context.addInstruction(new ReturnInstruction(node.source()));
+                context = context.addInstruction(new ReturnInstruction(body.source()));
             }
             case TypedFunctionStatementBehaviour.Terminate terminate -> {
             }
         }
 
-        var body = context.instructions;
+        var bodyInstructions = context.instructions;
 
         context = context.exitBlock();
 
         var freeVariables = FreeVariables.builder();
-        for (var shedFreeVariable : node.body().freeVariables()) {
+        for (var shedFreeVariable : body.freeVariables()) {
             var freeVariableLocalName = context.shedVariableToLocal(shedFreeVariable.name());
             for (var freeVariableSource : shedFreeVariable.referenceSources()) {
                 freeVariables = freeVariables.plus(
@@ -235,20 +239,47 @@ public class StackCompiler {
         }
 
         var defineFunctionInstruction = new DefineFunctionInstruction(
-            node.name(),
+            name,
             positionalParams,
             namedParams,
             freeVariables.build(),
-            body,
-            node.source()
+            bodyInstructions,
+            source
+        );
+
+        return context.addInstruction(defineFunctionInstruction);
+    }
+
+    private static Context compileFunctionDefinition(
+        TypedFunctionDefinitionNode node,
+        Context context
+    ) {
+        context = compileFunction(
+            node.name(),
+            node.signature(),
+            node.body(),
+            node.source(),
+            context
         );
 
         var localName = context.shedVariableToLocal(node.name());
         var storeInstruction = new LocalStoreInstruction(localName, node.source());
 
-        return context
-            .addInstruction(defineFunctionInstruction)
-            .addInstruction(storeInstruction);
+        return context.addInstruction(storeInstruction);
+    }
+
+    private static Context compileFunctionExpression(
+        TypedFunctionExpressionNode node,
+        Context context
+    ) {
+        return compileFunction(
+            // TODO: include source location?
+            "anonymous",
+            node.signature(),
+            node.body(),
+            node.source(),
+            context
+        );
     }
 
     private static Context compileFunctionReturn(
-- 
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