Store params and vals as locals in Patio

11 files changed, 156 insertions, 140 deletions

diff --git a/src/main/java/org/shedlang/compiler/backends/llvm/LlvmPatioCodeGen.java b/src/main/java/org/shedlang/compiler/backends/llvm/LlvmPatioCodeGen.java
index 96866b50..e74651bd 100644
--- a/src/main/java/org/shedlang/compiler/backends/llvm/LlvmPatioCodeGen.java
+++ b/src/main/java/org/shedlang/compiler/backends/llvm/LlvmPatioCodeGen.java
@@ -17,6 +17,7 @@ import org.shedlang.compiler.util.P;
 
 import java.util.List;
 import java.util.Optional;
+import java.util.stream.StreamSupport;
 
 public class LlvmPatioCodeGen {
     public static LlvmModule generateCompilationUnit(PatioCompilationUnit patioCompilationUnit) {
@@ -125,11 +126,7 @@ public class LlvmPatioCodeGen {
     ) {
         var functionContext = context.enterFunction();
 
-        var patioLocals = Lists.concat(
-            patioFunctionDefinition.params(),
-            patioFunctionDefinition.locals()
-        );
-        for (var patioLocal : patioLocals) {
+        for (var patioLocal : patioFunctionDefinition.locals()) {
             functionContext = functionContext.addPatioLocalToType(
                 patioLocal.ref(),
                 patioTypeToLlvmType(patioLocal.type())
@@ -153,7 +150,7 @@ public class LlvmPatioCodeGen {
         return context.addTopLevelEntity(new LlvmFunctionDefinition(
             patioFunctionDefinition.name(),
             patioTypeToLlvmType(patioFunctionDefinition.returnType()),
-            patioFunctionDefinition.params().stream()
+            StreamSupport.stream(patioFunctionDefinition.params().spliterator(), false)
                 .map(patioParam -> new LlvmParam(
                     patioTypeToLlvmType(patioParam.type()),
                     patioParam.name()
diff --git a/src/main/java/org/shedlang/compiler/backends/wasm/WasmPatioCodeGen.java b/src/main/java/org/shedlang/compiler/backends/wasm/WasmPatioCodeGen.java
index f7b5d8c8..5d6111ed 100644
--- a/src/main/java/org/shedlang/compiler/backends/wasm/WasmPatioCodeGen.java
+++ b/src/main/java/org/shedlang/compiler/backends/wasm/WasmPatioCodeGen.java
@@ -17,6 +17,7 @@ import org.shedlang.compiler.util.P;
 
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
+import java.util.ArrayList;
 import java.util.List;
 
 public class WasmPatioCodeGen {
@@ -71,13 +72,20 @@ public class WasmPatioCodeGen {
                 case PatioFunctionDefinition patioFunctionDefinition -> {
                     var name = patioFunctionDefinition.name();
 
-                    var wasmParams = patioFunctionDefinition.params().stream()
-                        .map(param -> patioLocalToWasmLocal(param))
-                        .toList();
-
-                    var wasmLocals = patioFunctionDefinition.locals().stream()
-                        .map(local -> patioLocalToWasmLocal(local))
-                        .toList();
+                    var wasmParams = new ArrayList<WasmLocal>();
+                    var wasmLocals = new ArrayList<WasmLocal>();
+
+                    for (var patioLocal : patioFunctionDefinition.locals()) {
+                        var wasmLocal = patioLocalToWasmLocal(patioLocal);
+                        switch (patioLocal) {
+                            case PatioLocal.Param patioParam -> {
+                                wasmParams.add(wasmLocal);
+                            }
+                            case PatioLocal.Val patioVal -> {
+                                wasmLocals.add(wasmLocal);
+                            }
+                        }
+                    }
 
                     var wasmResultTypes = patioTypeToWasmResultTypes(patioFunctionDefinition.returnType());
 
diff --git a/src/main/java/org/shedlang/compiler/patio/PatioCodeGen.java b/src/main/java/org/shedlang/compiler/patio/PatioCodeGen.java
index 11189e7b..e11f5dd1 100644
--- a/src/main/java/org/shedlang/compiler/patio/PatioCodeGen.java
+++ b/src/main/java/org/shedlang/compiler/patio/PatioCodeGen.java
@@ -39,7 +39,7 @@ public class PatioCodeGen {
             PatioTypes.INT,
             source,
             mainContext -> {
-                var namespaceValueResult = mainContext.allocateLocal(
+                var namespaceValueResult = mainContext.allocateVal(
                     PatioCodeGenLocalSpace.NAMESPACE_VALUE,
                     PatioCodeGenTypes.VALUE_TYPE
                 );
@@ -53,7 +53,7 @@ public class PatioCodeGen {
                     mainContext
                 );
 
-                var mainFieldResult = mainContext.allocateLocal(
+                var mainFieldResult = mainContext.allocateVal(
                     PatioCodeGenLocalSpace.MAIN,
                     PatioCodeGenTypes.VALUE_TYPE
                 );
@@ -70,7 +70,7 @@ public class PatioCodeGen {
                     mainContext
                 );
 
-                var exitCodeResult = mainContext.allocateLocal(
+                var exitCodeResult = mainContext.allocateVal(
                     PatioCodeGenLocalSpace.MAIN,
                     PatioCodeGenTypes.VALUE_TYPE
                 );
@@ -131,7 +131,7 @@ public class PatioCodeGen {
             case CallInstruction call -> {
                 var namedArgsByName = new ArrayList<Map.Entry<String, PatioLocalRef>>();
                 for (var argName : reversed(call.namedArgNames())) {
-                    var argResult = context.allocateLocal(
+                    var argResult = context.allocateVal(
                         PatioCodeGenLocalSpace.CALL_ARG_NAMED,
                         argName,
                         PatioCodeGenTypes.VALUE_TYPE
@@ -149,7 +149,7 @@ public class PatioCodeGen {
 
                 var positionalArgs = new ArrayList<PatioLocalRef>();
                 for (var i = 0; i < call.positionalArgCount(); i++) {
-                    var argResult = context.allocateLocal(
+                    var argResult = context.allocateVal(
                         PatioCodeGenLocalSpace.CALL_ARG_POSITIONAL,
                         Integer.toString(call.positionalArgCount() - i - 1),
                         PatioCodeGenTypes.VALUE_TYPE
@@ -166,7 +166,7 @@ public class PatioCodeGen {
                 }
                 Collections.reverse(positionalArgs);
 
-                var receiverResult = context.allocateLocal(
+                var receiverResult = context.allocateVal(
                     PatioCodeGenLocalSpace.RECEIVER,
                     PatioCodeGenTypes.VALUE_TYPE
                 );
@@ -178,7 +178,7 @@ public class PatioCodeGen {
                     stackIrInstruction.source()
                 );
 
-                var targetResult = context.allocateLocal(
+                var targetResult = context.allocateVal(
                     PatioCodeGenLocalSpace.TEMPORARY,
                     PatioCodeGenTypes.VALUE_TYPE
                 );
@@ -196,7 +196,7 @@ public class PatioCodeGen {
             }
 
             case DefineFunctionInstruction defineFunction -> {
-                var targetResult = context.allocateLocal(
+                var targetResult = context.allocateVal(
                     PatioCodeGenLocalSpace.CLOSURE,
                     defineFunction.name(),
                     PatioCodeGenTypes.VALUE_TYPE
@@ -229,7 +229,7 @@ public class PatioCodeGen {
                 var receiver = receiverResult.value();
                 context = receiverResult.context();
 
-                var targetResult = context.allocateLocal(
+                var targetResult = context.allocateVal(
                     PatioCodeGenLocalSpace.TEMPORARY,
                     fieldLoad.fieldName(),
                     PatioCodeGenTypes.VALUE_TYPE
@@ -252,7 +252,7 @@ public class PatioCodeGen {
             }
 
             case IfInstruction if_ -> {
-                var conditionIntResult = context.allocateLocal(
+                var conditionIntResult = context.allocateVal(
                     PatioCodeGenLocalSpace.TEMPORARY,
                     "conditionInt",
                     PatioTypes.INT
@@ -262,7 +262,7 @@ public class PatioCodeGen {
 
                 context = context.temporaryPopIntoLocal(conditionInt, if_.source());
 
-                var conditionBoolResult = context.allocateLocal(
+                var conditionBoolResult = context.allocateVal(
                     PatioCodeGenLocalSpace.TEMPORARY,
                     "conditionBool",
                     PatioTypes.BOOL
@@ -276,7 +276,7 @@ public class PatioCodeGen {
                     if_.source()
                 ));
 
-                var valueResult = context.allocateLocal(
+                var valueResult = context.allocateVal(
                     PatioCodeGenLocalSpace.TEMPORARY,
                     PatioCodeGenTypes.VALUE_TYPE
                 );
@@ -361,7 +361,7 @@ public class PatioCodeGen {
             }
 
             case LocalStoreInstruction localStore ->
-                context.addStackIrLocal(
+                context.addStackIrVal(
                     localStore.name(),
                     (local, c) -> c.temporaryPopIntoLocal(local, localStore.source())
                 );
@@ -383,7 +383,7 @@ public class PatioCodeGen {
             }
 
             case NamespaceImportInstruction namespaceImport -> {
-                var namespaceValueResult = context.allocateLocal(
+                var namespaceValueResult = context.allocateVal(
                     PatioCodeGenLocalSpace.NAMESPACE_VALUE,
                     PatioCodeGenNamespaces.NAMESPACE_VALUE_TYPE
                 );
@@ -417,7 +417,7 @@ public class PatioCodeGen {
                 var stringPtrOperand = stringPtrOperandResult.value();
                 context = stringPtrOperandResult.context();
 
-                var stringPtrResult = context.allocateLocal(
+                var stringPtrResult = context.allocateVal(
                     PatioCodeGenLocalSpace.STRING,
                     PatioCodeGenTypes.VALUE_TYPE
                 );
@@ -477,7 +477,7 @@ public class PatioCodeGen {
     ) {
         return generateBinaryOperation(
             (target, left, right, operationContext) -> {
-                var targetBoolResult = operationContext.allocateLocal(
+                var targetBoolResult = operationContext.allocateVal(
                     PatioCodeGenLocalSpace.TEMPORARY,
                     PatioTypes.INT
                 );
@@ -515,7 +515,7 @@ public class PatioCodeGen {
         var left = leftResult.value();
         context = leftResult.context();
 
-        var targetResult = context.allocateLocal(
+        var targetResult = context.allocateVal(
             PatioCodeGenLocalSpace.TEMPORARY,
             PatioCodeGenTypes.VALUE_TYPE
         );
@@ -554,7 +554,7 @@ public class PatioCodeGen {
     }
 
     private static PatioCodeGenContext pushValue(int value, Source source, PatioCodeGenContext context) {
-        var localResult = context.allocateLocal(PatioCodeGenLocalSpace.TEMPORARY, PatioCodeGenTypes.VALUE_TYPE);
+        var localResult = context.allocateVal(PatioCodeGenLocalSpace.TEMPORARY, PatioCodeGenTypes.VALUE_TYPE);
         var local = localResult.value();
         context = localResult.context();
 
diff --git a/src/main/java/org/shedlang/compiler/patio/PatioCodeGenClosures.java b/src/main/java/org/shedlang/compiler/patio/PatioCodeGenClosures.java
index c0cb41ea..cba3b17b 100644
--- a/src/main/java/org/shedlang/compiler/patio/PatioCodeGenClosures.java
+++ b/src/main/java/org/shedlang/compiler/patio/PatioCodeGenClosures.java
@@ -64,23 +64,21 @@ class PatioCodeGenClosures {
         context = fullNameResult.context();
 
         context = context.createFunction(fullName, PatioVisibility.PRIVATE, PatioCodeGenTypes.VALUE_TYPE, source, bodyContext -> {
-            var closurePointerResult = bodyContext.allocateLocal(
+            var closurePointerResult = bodyContext.allocateParam(
                 PatioCodeGenLocalSpace.CLOSURE_POINTER,
                 CLOSURE_POINTER_TYPE
             );
             var closurePointer = closurePointerResult.value();
             bodyContext = closurePointerResult.context();
 
-            bodyContext = bodyContext.addArg(closurePointer);
-
             var stackIrParams = Stream.concat(positionalParams.stream(), namedParams.stream()).toList();
 
             for (var stackIrParam : stackIrParams) {
-                bodyContext = bodyContext.addStackIrArg(stackIrParam.name());
+                bodyContext = bodyContext.addStackIrParam(stackIrParam.name());
             }
 
             for (var freeVariable : freeVariables) {
-                bodyContext = bodyContext.addStackIrLocal(
+                bodyContext = bodyContext.addStackIrVal(
                     freeVariable.name(),
                     (freeVariableLocal, c) -> c.addInstruction(new PatioMemoryLoad(
                         freeVariableLocal,
@@ -97,7 +95,7 @@ class PatioCodeGenClosures {
             return bodyContext;
         });
 
-        var closurePointerResult = context.allocateLocal(
+        var closurePointerResult = context.allocateVal(
             PatioCodeGenLocalSpace.CLOSURE_POINTER,
             name,
             PatioTypes.DATA_POINTER
@@ -146,7 +144,7 @@ class PatioCodeGenClosures {
         Source source,
         PatioCodeGenContext context
     ) {
-        var closurePointerResult = context.allocateLocal(
+        var closurePointerResult = context.allocateVal(
             PatioCodeGenLocalSpace.CLOSURE_POINTER,
             CLOSURE_POINTER_TYPE
         );
@@ -159,7 +157,7 @@ class PatioCodeGenClosures {
             source
         ));
 
-        var functionPointerResult = context.allocateLocal(
+        var functionPointerResult = context.allocateVal(
             PatioCodeGenLocalSpace.CALL_FUNCTION_POINTER,
             PatioTypes.FUNCTION_POINTER
         );
diff --git a/src/main/java/org/shedlang/compiler/patio/PatioCodeGenContext.java b/src/main/java/org/shedlang/compiler/patio/PatioCodeGenContext.java
index 17052735..ecec3aee 100644
--- a/src/main/java/org/shedlang/compiler/patio/PatioCodeGenContext.java
+++ b/src/main/java/org/shedlang/compiler/patio/PatioCodeGenContext.java
@@ -87,16 +87,14 @@ public record PatioCodeGenContext(
         PVector<PatioInstruction> instructions,
         OrderedPMap<String, PatioLocal> localsByName,
         PMap<String, PatioLocalRef> stackIrNameToLocal,
-        PMap<String, PVector<Function<PatioCodeGenContext, PatioCodeGenContext>>> waitingForStackIrLocal,
-        PVector<PatioLocalRef> args
+        PMap<String, PVector<Function<PatioCodeGenContext, PatioCodeGenContext>>> waitingForStackIrLocal
     ) {
         public static final FunctionContext EMPTY = new FunctionContext(
             P.stack(),
             P.vector(),
             OrderedPMap.empty(),
             P.map(),
-            P.map(),
-            P.vector()
+            P.map()
         );
 
         public Result<PatioLocalRef> temporaryPop() {
@@ -105,8 +103,7 @@ public record PatioCodeGenContext(
                 this.instructions,
                 this.localsByName,
                 this.stackIrNameToLocal,
-                this.waitingForStackIrLocal,
-                this.args
+                this.waitingForStackIrLocal
             ).toResult(this.temporaryStack.get(0));
         }
 
@@ -116,8 +113,7 @@ public record PatioCodeGenContext(
                 this.instructions,
                 this.localsByName,
                 this.stackIrNameToLocal,
-                this.waitingForStackIrLocal,
-                this.args
+                this.waitingForStackIrLocal
             );
         }
 
@@ -127,15 +123,15 @@ public record PatioCodeGenContext(
                 this.instructions.plus(instruction),
                 this.localsByName,
                 this.stackIrNameToLocal,
-                this.waitingForStackIrLocal,
-                this.args
+                this.waitingForStackIrLocal
             );
         }
 
         public Result<PatioLocalRef> allocateLocal(
             PatioCodeGenLocalSpace space,
             Optional<String> name,
-            PatioType type
+            PatioType type,
+            PatioLocalFactory createLocal
         ) {
             var fullName = NameAllocator.allocateName(
                 this.localsByName::containsKey,
@@ -146,14 +142,16 @@ public record PatioCodeGenContext(
             return new FunctionContext(
                 this.temporaryStack,
                 this.instructions,
-                this.localsByName.plus(fullName, new PatioLocal(fullName, type)),
+                this.localsByName.plus(fullName, createLocal.create(fullName, type)),
                 this.stackIrNameToLocal,
-                this.waitingForStackIrLocal,
-                this.args
+                this.waitingForStackIrLocal
             ).toResult(new PatioLocalRef(fullName));
         }
 
-        public Result<PVector<Function<PatioCodeGenContext, PatioCodeGenContext>>> addStackIrLocal(String name) {
+        public Result<PVector<Function<PatioCodeGenContext, PatioCodeGenContext>>> addStackIrLocal(
+            String name,
+            PatioLocalFactory createLocal
+        ) {
             var context = this;
 
             if (this.stackIrNameToLocal.containsKey(name)) {
@@ -174,12 +172,11 @@ public record PatioCodeGenContext(
                 this.instructions,
                 this.localsByName.plus(
                     fullName,
-                    new PatioLocal(fullName, PatioCodeGenTypes.VALUE_TYPE)
+                    createLocal.create(fullName, PatioCodeGenTypes.VALUE_TYPE)
                 ),
                 // TODO: the mapping is redundant given we fix the mapping
                 this.stackIrNameToLocal.plus(name, localRef),
-                this.waitingForStackIrLocal.minus(name),
-                this.args
+                this.waitingForStackIrLocal.minus(name)
             );
 
             return context.toResult(this.waitingForStackIrLocal.getOrDefault(name, P.vector()));
@@ -214,19 +211,7 @@ public record PatioCodeGenContext(
                 this.waitingForStackIrLocal.plus(
                     name,
                     this.waitingForStackIrLocal.getOrDefault(name, P.vector()).plus(func)
-                ),
-                this.args
-            );
-        }
-
-        public FunctionContext addArg(PatioLocalRef local) {
-            return new FunctionContext(
-                this.temporaryStack,
-                this.instructions,
-                this.localsByName,
-                this.stackIrNameToLocal,
-                this.waitingForStackIrLocal,
-                this.args.plus(local)
+                )
             );
         }
 
@@ -314,37 +299,83 @@ public record PatioCodeGenContext(
         return withFunctionContext(this.functionContext.addInstruction(instruction));
     }
 
-    public PatioCodeGenResult<PatioLocalRef> allocateLocal(
+    public PatioCodeGenResult<PatioLocalRef> allocateParam(
+        PatioCodeGenLocalSpace space,
+        PatioType type
+    ) {
+        var result = this.functionContext.allocateLocal(
+            space,
+            Optional.empty(),
+            type,
+            PatioLocal.Param::new
+        );
+
+        return withFunctionContextResult(result);
+    }
+
+    public PatioCodeGenResult<PatioLocalRef> allocateParam(
         PatioCodeGenLocalSpace space,
         String name,
         PatioType type
     ) {
-        var result = this.functionContext.allocateLocal(space, Optional.of(name), type);
+        var result = this.functionContext.allocateLocal(
+            space,
+            Optional.of(name),
+            type,
+            PatioLocal.Param::new
+        );
 
         return withFunctionContextResult(result);
     }
 
-    public PatioCodeGenResult<PatioLocalRef> allocateLocal(
+    public PatioCodeGenResult<PatioLocalRef> allocateVal(
         PatioCodeGenLocalSpace space,
         PatioType type
     ) {
-        var result = this.functionContext.allocateLocal(space, Optional.empty(), type);
+        var result = this.functionContext.allocateLocal(
+            space,
+            Optional.empty(),
+            type,
+            PatioLocal.Val::new
+        );
 
         return withFunctionContextResult(result);
     }
 
-    public PatioCodeGenContext addStackIrArg(String name) {
-        return addStackIrLocal(
-            name,
-            (local, c) -> c.addArg(local)
+    public PatioCodeGenResult<PatioLocalRef> allocateVal(
+        PatioCodeGenLocalSpace space,
+        String name,
+        PatioType type
+    ) {
+        var result = this.functionContext.allocateLocal(
+            space,
+            Optional.of(name),
+            type,
+            PatioLocal.Val::new
         );
+
+        return withFunctionContextResult(result);
     }
 
-    public PatioCodeGenContext addStackIrLocal(
+    public PatioCodeGenContext addStackIrParam(
+        String name
+    ) {
+        return addStackIrLocal(name, (l, c) -> c, PatioLocal.Param::new);
+    }
+
+    public PatioCodeGenContext addStackIrVal(
         String name,
         BiFunction<PatioLocalRef, PatioCodeGenContext, PatioCodeGenContext> setLocal
     ) {
-        var result = this.functionContext.addStackIrLocal(name);
+        return addStackIrLocal(name, setLocal, PatioLocal.Val::new);
+    }
+
+    public PatioCodeGenContext addStackIrLocal(
+        String name,
+        BiFunction<PatioLocalRef, PatioCodeGenContext, PatioCodeGenContext> setLocal,
+        PatioLocalFactory createLocal
+    ) {
+        var result = this.functionContext.addStackIrLocal(name, createLocal);
 
         var context = withFunctionContext(result.context);
         var patioLocal = context.functionContext.stackIrLocalNameToLocal(name);
@@ -377,10 +408,6 @@ public record PatioCodeGenContext(
         return this.functionContext.stackIrLocalNameToLocal(name);
     }
 
-    public PatioCodeGenContext addArg(PatioLocalRef local) {
-        return withFunctionContext(this.functionContext.addArg(local));
-    }
-
     public PatioCodeGenContext createFunction(
         String name,
         PatioVisibility visibility,
@@ -396,22 +423,12 @@ public record PatioCodeGenContext(
 
         bodyContext = createBody.apply(bodyContext);
 
-        var params = new ArrayList<PatioLocal>();
-        var locals = new ArrayList<PatioLocal>();
-
-        for (var local : bodyContext.functionContext.localsByName.values()) {
-            if (bodyContext.functionContext.args.contains(new PatioLocalRef(local.name()))) {
-                params.add(local);
-            } else {
-                locals.add(local);
-            }
-        }
+        var locals = bodyContext.functionContext.localsByName.values().stream().toList();
 
         return new PatioCodeGenContext(
             bodyContext.compilationUnitContext.addElement(new PatioFunctionDefinition(
                 name,
                 visibility,
-                params,
                 locals,
                 returnType,
                 bodyContext.functionContext.instructions,
@@ -431,17 +448,12 @@ public record PatioCodeGenContext(
                 P.vector(),
                 this.functionContext.localsByName,
                 this.functionContext.stackIrNameToLocal,
-                this.functionContext.waitingForStackIrLocal,
-                P.vector()
+                this.functionContext.waitingForStackIrLocal
             )
         );
     }
 
     public PatioCodeGenResult<List<PatioInstruction>> exitBlock() {
-        if (!this.functionContext.args.isEmpty()) {
-            throw new RuntimeException("cannot add args in block");
-        }
-
         if (!this.functionContext.temporaryStack.isEmpty()) {
             throw new RuntimeException("temporary stack must be empty at the end of a block");
         }
@@ -454,8 +466,7 @@ public record PatioCodeGenContext(
                 this.blockStack.get(0).instructions,
                 this.functionContext.localsByName,
                 this.functionContext.stackIrNameToLocal,
-                this.functionContext.waitingForStackIrLocal,
-                this.blockStack.get(0).args
+                this.functionContext.waitingForStackIrLocal
             )
         ).toResult(this.functionContext.instructions);
     }
@@ -486,4 +497,8 @@ public record PatioCodeGenContext(
             source
         );
     }
+
+    private interface PatioLocalFactory {
+        PatioLocal create(String name, PatioType type);
+    }
 }
diff --git a/src/main/java/org/shedlang/compiler/patio/PatioCodeGenNamespaces.java b/src/main/java/org/shedlang/compiler/patio/PatioCodeGenNamespaces.java
index afec18f4..e87adb5e 100644
--- a/src/main/java/org/shedlang/compiler/patio/PatioCodeGenNamespaces.java
+++ b/src/main/java/org/shedlang/compiler/patio/PatioCodeGenNamespaces.java
@@ -75,7 +75,7 @@ public class PatioCodeGenNamespaces {
             NAMESPACE_VALUE_TYPE,
             source,
             importContext -> {
-                var isInitedResult = importContext.allocateLocal(
+                var isInitedResult = importContext.allocateVal(
                     PatioCodeGenLocalSpace.TEMPORARY,
                     PatioTypes.BOOL
                 );
@@ -113,7 +113,7 @@ public class PatioCodeGenNamespaces {
                     source
                 ));
 
-                var namespaceValueResult = importContext.allocateLocal(
+                var namespaceValueResult = importContext.allocateVal(
                     PatioCodeGenLocalSpace.TEMPORARY,
                     NAMESPACE_VALUE_TYPE
                 );
@@ -174,7 +174,7 @@ public class PatioCodeGenNamespaces {
         var namespaceTypeInfo = context.namespaceTypeInfo(namespaceName);
         var layout = namespaceDataLayout(namespaceTypeInfo);
 
-        var namespacePointerResult = context.allocateLocal(
+        var namespacePointerResult = context.allocateVal(
             PatioCodeGenLocalSpace.NAMESPACE_POINTER,
             namespaceNameToPatioIdentifier(namespaceName),
             PatioTypes.DATA_POINTER
diff --git a/src/main/java/org/shedlang/compiler/patio/PatioCodeGenStrings.java b/src/main/java/org/shedlang/compiler/patio/PatioCodeGenStrings.java
index 098d0296..a1de8092 100644
--- a/src/main/java/org/shedlang/compiler/patio/PatioCodeGenStrings.java
+++ b/src/main/java/org/shedlang/compiler/patio/PatioCodeGenStrings.java
@@ -63,8 +63,8 @@ public class PatioCodeGenStrings {
         context = context.addCompilationUnitElement(new PatioFunctionDeclaration(
             runtimeAddName,
             List.of(
-                new PatioLocal("left", PatioCodeGenTypes.VALUE_TYPE),
-                new PatioLocal("right", PatioCodeGenTypes.VALUE_TYPE)
+                new PatioLocal.Param("left", PatioCodeGenTypes.VALUE_TYPE),
+                new PatioLocal.Param("right", PatioCodeGenTypes.VALUE_TYPE)
             ),
             PatioCodeGenTypes.VALUE_TYPE,
             source
diff --git a/src/main/java/org/shedlang/compiler/patio/ast/PatioFunctionDeclaration.java b/src/main/java/org/shedlang/compiler/patio/ast/PatioFunctionDeclaration.java
index 28810b5e..13b505b4 100644
--- a/src/main/java/org/shedlang/compiler/patio/ast/PatioFunctionDeclaration.java
+++ b/src/main/java/org/shedlang/compiler/patio/ast/PatioFunctionDeclaration.java
@@ -11,7 +11,7 @@ import java.util.List;
 
 public record PatioFunctionDeclaration(
     String name,
-    List<PatioLocal> params,
+    List<PatioLocal.Param> params,
     PatioType returnType,
     Source source
 ) implements PatioCompilationUnitElement {
@@ -25,7 +25,7 @@ public record PatioFunctionDeclaration(
 
     public record Builder(
         String name,
-        PVector<PatioLocal> params,
+        PVector<PatioLocal.Param> params,
         PatioType returnType
     ) {
         public Builder withName(String name) {
@@ -36,7 +36,7 @@ public record PatioFunctionDeclaration(
             );
         }
 
-        public Builder addParam(PatioLocal param) {
+        public Builder addParam(PatioLocal.Param param) {
             return new Builder(
                 this.name,
                 this.params.plus(param),
diff --git a/src/main/java/org/shedlang/compiler/patio/ast/PatioFunctionDefinition.java b/src/main/java/org/shedlang/compiler/patio/ast/PatioFunctionDefinition.java
index 78bb2b33..16790151 100644
--- a/src/main/java/org/shedlang/compiler/patio/ast/PatioFunctionDefinition.java
+++ b/src/main/java/org/shedlang/compiler/patio/ast/PatioFunctionDefinition.java
@@ -6,6 +6,7 @@ import org.shedlang.compiler.patio.ast.types.PatioType;
 import org.shedlang.compiler.patio.ast.types.PatioTypes;
 import org.shedlang.compiler.sources.Source;
 import org.shedlang.compiler.sources.Sources;
+import org.shedlang.compiler.util.Iterables;
 import org.shedlang.compiler.util.P;
 
 import java.util.List;
@@ -13,18 +14,20 @@ import java.util.List;
 public record PatioFunctionDefinition(
     String name,
     PatioVisibility visibility,
-    List<PatioLocal> params,
     List<PatioLocal> locals,
     PatioType returnType,
     List<PatioInstruction> body,
     Source source
 ) implements PatioCompilationUnitElement {
+    public Iterable<PatioLocal.Param> params() {
+        return Iterables.filterToType(locals, PatioLocal.Param.class);
+    }
+
     public static Builder builder() {
         return new Builder(
             "f",
             PatioVisibility.PRIVATE,
             P.vector(),
-            P.vector(),
             PatioTypes.INT,
             P.vector()
         );
@@ -33,7 +36,6 @@ public record PatioFunctionDefinition(
     public record Builder(
         String name,
         PatioVisibility visibility,
-        PVector<PatioLocal> params,
         PVector<PatioLocal> locals,
         PatioType returnType,
         PVector<PatioInstruction> body
@@ -42,7 +44,6 @@ public record PatioFunctionDefinition(
             return new Builder(
                 name,
                 this.visibility,
-                this.params,
                 this.locals,
                 this.returnType,
                 this.body
@@ -53,18 +54,6 @@ public record PatioFunctionDefinition(
             return new Builder(
                 this.name,
                 visibility,
-                this.params,
-                this.locals,
-                this.returnType,
-                this.body
-            );
-        }
-
-        public Builder addParam(PatioLocal param) {
-            return new Builder(
-                this.name,
-                this.visibility,
-                this.params.plus(param),
                 this.locals,
                 this.returnType,
                 this.body
@@ -75,7 +64,6 @@ public record PatioFunctionDefinition(
             return new Builder(
                 this.name,
                 this.visibility,
-                this.params,
                 this.locals.plus(local),
                 this.returnType,
                 this.body
@@ -86,7 +74,6 @@ public record PatioFunctionDefinition(
             return new Builder(
                 this.name,
                 this.visibility,
-                this.params,
                 this.locals,
                 this.returnType,
                 this.body.plus(instruction)
@@ -97,7 +84,6 @@ public record PatioFunctionDefinition(
             return new Builder(
                 this.name,
                 this.visibility,
-                this.params,
                 this.locals,
                 returnType,
                 this.body
@@ -108,7 +94,6 @@ public record PatioFunctionDefinition(
             return new PatioFunctionDefinition(
                 this.name,
                 this.visibility,
-                this.params,
                 this.locals,
                 this.returnType,
                 this.body,
diff --git a/src/main/java/org/shedlang/compiler/patio/ast/PatioLocal.java b/src/main/java/org/shedlang/compiler/patio/ast/PatioLocal.java
index eda09d2c..24f32ca4 100644
--- a/src/main/java/org/shedlang/compiler/patio/ast/PatioLocal.java
+++ b/src/main/java/org/shedlang/compiler/patio/ast/PatioLocal.java
@@ -3,8 +3,14 @@ package org.shedlang.compiler.patio.ast;
 import org.shedlang.compiler.patio.ast.operands.PatioLocalRef;
 import org.shedlang.compiler.patio.ast.types.PatioType;
 
-public record PatioLocal(String name, PatioType type) {
-    public PatioLocalRef ref() {
-        return new PatioLocalRef(name);
+public sealed interface PatioLocal {
+    String name();
+    PatioType type();
+
+    record Param(String name, PatioType type) implements PatioLocal {}
+    record Val(String name, PatioType type) implements PatioLocal {}
+
+    default PatioLocalRef ref() {
+        return new PatioLocalRef(name());
     }
 }
diff --git a/src/main/java/org/shedlang/compiler/patio/ast/PatioSerializer.java b/src/main/java/org/shedlang/compiler/patio/ast/PatioSerializer.java
index 74165bdc..3fd95306 100644
--- a/src/main/java/org/shedlang/compiler/patio/ast/PatioSerializer.java
+++ b/src/main/java/org/shedlang/compiler/patio/ast/PatioSerializer.java
@@ -112,11 +112,6 @@ public class PatioSerializer {
                     treeIdentifier("function"),
                     treeString(element.name()),
                     treeNamed("visibility", visibilityToTree(functionDefinition.visibility())),
-                    treeNamed("params", treeList(
-                        functionDefinition.params().stream()
-                            .map(param -> localToTree(param))
-                            .toList()
-                    )),
                     treeNamed("locals", treeList(
                         functionDefinition.locals().stream()
                             .map(local -> localToTree(local))
@@ -307,7 +302,19 @@ public class PatioSerializer {
     }
 
     private static Tree localToTree(PatioLocal local) {
-        return treeList(treeString(local.name()), typeToTree(local.type()));
+        var localType = switch (local) {
+            case PatioLocal.Param param ->
+                "param";
+
+            case PatioLocal.Val val ->
+                "val";
+        };
+
+        return treeList(
+            treeIdentifier(localType),
+            treeString(local.name()),
+            typeToTree(local.type())
+        );
     }
 
     private static Tree optionalOperandToTree(Optional<PatioLocalRef> target) {