From 927ae58be68fcf2a541c1af2a7b27d845e97dea6 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Sun, 29 Oct 2023 20:42:56 +0000
Subject: Parse params without types

---
 .../compiler/ast/untyped/UntypedFunctionSignatureNode.java  |  6 ++++--
 .../org/shedlang/compiler/ast/untyped/UntypedParamNode.java |  4 +++-
 src/main/java/org/shedlang/compiler/parser/Parser.java      | 13 ++++++++-----
 .../java/org/shedlang/compiler/typechecker/TypeChecker.java |  3 ++-
 4 files changed, 17 insertions(+), 9 deletions(-)

(limited to 'src/main/java')

diff --git a/src/main/java/org/shedlang/compiler/ast/untyped/UntypedFunctionSignatureNode.java b/src/main/java/org/shedlang/compiler/ast/untyped/UntypedFunctionSignatureNode.java
index dea78312..4920e253 100644
--- a/src/main/java/org/shedlang/compiler/ast/untyped/UntypedFunctionSignatureNode.java
+++ b/src/main/java/org/shedlang/compiler/ast/untyped/UntypedFunctionSignatureNode.java
@@ -40,8 +40,9 @@ public record UntypedFunctionSignatureNode(
         }
 
         public Builder addPositionalParam(String name, UntypedTypeLevelExpressionNode type) {
+            var paramNode = new UntypedParamNode(name, Optional.of(type), Sources.NULL);
             return new Builder(
-                this.positionalParams.plus(new UntypedParamNode(name, type, Sources.NULL)),
+                this.positionalParams.plus(paramNode),
                 this.namedParams,
                 this.effect,
                 this.returnType,
@@ -50,9 +51,10 @@ public record UntypedFunctionSignatureNode(
         }
 
         public Builder addNamedParam(String name, UntypedTypeLevelExpressionNode type) {
+            var paramNode = new UntypedParamNode(name, Optional.of(type), Sources.NULL);
             return new Builder(
                 this.positionalParams,
-                this.namedParams.plus(new UntypedParamNode(name, type, Sources.NULL)),
+                this.namedParams.plus(paramNode),
                 this.effect,
                 this.returnType,
                 this.body
diff --git a/src/main/java/org/shedlang/compiler/ast/untyped/UntypedParamNode.java b/src/main/java/org/shedlang/compiler/ast/untyped/UntypedParamNode.java
index 323d9333..366de81c 100644
--- a/src/main/java/org/shedlang/compiler/ast/untyped/UntypedParamNode.java
+++ b/src/main/java/org/shedlang/compiler/ast/untyped/UntypedParamNode.java
@@ -2,9 +2,11 @@ package org.shedlang.compiler.ast.untyped;
 
 import org.shedlang.compiler.sources.Source;
 
+import java.util.Optional;
+
 public record UntypedParamNode(
     String name,
-    UntypedTypeLevelExpressionNode type,
+    Optional<UntypedTypeLevelExpressionNode> type,
     Source source
 ) implements UntypedNode {
 }
diff --git a/src/main/java/org/shedlang/compiler/parser/Parser.java b/src/main/java/org/shedlang/compiler/parser/Parser.java
index a0edcd9b..cf01705d 100644
--- a/src/main/java/org/shedlang/compiler/parser/Parser.java
+++ b/src/main/java/org/shedlang/compiler/parser/Parser.java
@@ -640,15 +640,18 @@ public class Parser {
                 var isNamed = tokens.trySkip(TokenType.SYMBOL_DOT);
 
                 var name = tokens.nextValue(TokenType.IDENTIFIER);
-                tokens.skip(TokenType.SYMBOL_COLON);
-                var type = parseTopLevelTypeLevelExpression(tokens);
-                if (!isNamed && !named.isEmpty()) {
-                    throw new PositionalParamAfterNamedParamError(type.source());
-                }
+
+                var type = tokens.trySkip(TokenType.SYMBOL_COLON)
+                    ? Optional.of(parseTopLevelTypeLevelExpression(tokens))
+                    : Optional.<UntypedTypeLevelExpressionNode>empty();
 
                 var paramEnd = tokens.position();
                 var paramSource = paramStart.to(paramEnd);
 
+                if (!isNamed && !named.isEmpty()) {
+                    throw new PositionalParamAfterNamedParamError(paramSource);
+                }
+
                 (isNamed ? named : positional).add(new UntypedParamNode(name, type, paramSource));
 
                 return null;
diff --git a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
index ee50f13d..db25ac3b 100644
--- a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
+++ b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
@@ -1047,7 +1047,8 @@ public class TypeChecker {
     ) {
         return new TypedParamNode(
             untyped.name(),
-            typeCheckTypeLevelExpression(TypeSets.META_TYPE, untyped.type(), context),
+            // TODO: handle param without type
+            typeCheckTypeLevelExpression(TypeSets.META_TYPE, untyped.type().orElseThrow(), context),
             untyped.source()
         );
     }
-- 
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