From 9d51478ffc90b4b7d059c38cae25beafe63eb40b Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Tue, 6 Jun 2023 20:03:43 +0100
Subject: Parse named arguments

---
 .../java/org/shedlang/compiler/parser/Parser.java  | 36 ++++++++++++++++++----
 .../org/shedlang/compiler/parser/TokenType.java    |  2 ++
 .../org/shedlang/compiler/parser/Tokeniser.java    |  2 ++
 3 files changed, 34 insertions(+), 6 deletions(-)

(limited to 'src/main/java')

diff --git a/src/main/java/org/shedlang/compiler/parser/Parser.java b/src/main/java/org/shedlang/compiler/parser/Parser.java
index 47c9d286..855634e7 100644
--- a/src/main/java/org/shedlang/compiler/parser/Parser.java
+++ b/src/main/java/org/shedlang/compiler/parser/Parser.java
@@ -31,18 +31,42 @@ public class Parser {
     }
 
     private static UntypedArgsNode parseArgs(TokenIterator<TokenType> tokens) {
-        var start = tokens.position();
+        var argsStart = tokens.position();
+
+        var positional = new ArrayList<UntypedExpressionNode>();
+        var named = new ArrayList<UntypedNamedArgNode>();
 
-        var positional = parseMany(
+        parseMany(
             () -> tokens.isNext(TokenType.SYMBOL_PAREN_CLOSE),
-            () -> parseTopLevelExpression(tokens),
+            () -> {
+                if (tokens.trySkip(TokenType.SYMBOL_DOT)) {
+                    var argStart = tokens.position();
+
+                    var argName = tokens.nextValue(TokenType.IDENTIFIER);
+                    tokens.skip(TokenType.SYMBOL_EQUALS);
+                    var expression = parseTopLevelExpression(tokens);
+
+                    var argEnd = tokens.position();
+                    var argSource = argStart.to(argEnd);
+
+                    named.add(new UntypedNamedArgNode(argName, expression, argSource));
+                } else {
+                    var expression = parseTopLevelExpression(tokens);
+                    // TODO:
+//                    if (named.isEmpty()) {
+//                        throw new PositionalArgAfterNamedArgError(tokens.peek());
+//                    }
+                    positional.add(expression);
+                }
+                return null;
+            },
             () -> tokens.trySkip(TokenType.SYMBOL_COMMA)
         );
 
-        var end = tokens.position();
-        var source = start.to(end);
+        var argsEnd = tokens.position();
+        var argsSource = argsStart.to(argsEnd);
 
-        return new UntypedArgsNode(positional, List.of(), source);
+        return new UntypedArgsNode(positional, named, argsSource);
     }
 
     private static <T> List<T> parseMany(
diff --git a/src/main/java/org/shedlang/compiler/parser/TokenType.java b/src/main/java/org/shedlang/compiler/parser/TokenType.java
index fe01939a..41f18350 100644
--- a/src/main/java/org/shedlang/compiler/parser/TokenType.java
+++ b/src/main/java/org/shedlang/compiler/parser/TokenType.java
@@ -11,6 +11,8 @@ public enum TokenType {
 
     SYMBOL_BANG,
     SYMBOL_COMMA,
+    SYMBOL_DOT,
+    SYMBOL_EQUALS,
     SYMBOL_PAREN_OPEN,
     SYMBOL_PAREN_CLOSE,
 }
diff --git a/src/main/java/org/shedlang/compiler/parser/Tokeniser.java b/src/main/java/org/shedlang/compiler/parser/Tokeniser.java
index 0475d799..e604609c 100644
--- a/src/main/java/org/shedlang/compiler/parser/Tokeniser.java
+++ b/src/main/java/org/shedlang/compiler/parser/Tokeniser.java
@@ -21,6 +21,8 @@ public class Tokeniser {
         List.of(
             RegexTokeniser.rule(TokenType.SYMBOL_BANG, "!"),
             RegexTokeniser.rule(TokenType.SYMBOL_COMMA, ","),
+            RegexTokeniser.rule(TokenType.SYMBOL_DOT, "\\."),
+            RegexTokeniser.rule(TokenType.SYMBOL_EQUALS, "="),
             RegexTokeniser.rule(TokenType.SYMBOL_PAREN_OPEN, "\\("),
             RegexTokeniser.rule(TokenType.SYMBOL_PAREN_CLOSE, "\\)"),
 
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