From ab8b25ab08620df482d88c0e729fb9f53bca9f61 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Tue, 6 Jun 2023 19:55:11 +0100
Subject: Parse positional arguments

---
 .../java/org/shedlang/compiler/parser/Parser.java  | 34 +++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

(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 6f5abb19..47c9d286 100644
--- a/src/main/java/org/shedlang/compiler/parser/Parser.java
+++ b/src/main/java/org/shedlang/compiler/parser/Parser.java
@@ -5,7 +5,10 @@ import org.shedlang.compiler.sources.Source;
 import org.shedlang.compiler.tokeniser.TokenIterator;
 import org.shedlang.compiler.tokeniser.UnexpectedTokenException;
 
+import java.util.ArrayList;
 import java.util.List;
+import java.util.function.BooleanSupplier;
+import java.util.function.Supplier;
 import java.util.regex.Pattern;
 
 public class Parser {
@@ -28,7 +31,36 @@ public class Parser {
     }
 
     private static UntypedArgsNode parseArgs(TokenIterator<TokenType> tokens) {
-        return new UntypedArgsNode(List.of(), List.of(), tokens.position());
+        var start = tokens.position();
+
+        var positional = parseMany(
+            () -> tokens.isNext(TokenType.SYMBOL_PAREN_CLOSE),
+            () -> parseTopLevelExpression(tokens),
+            () -> tokens.trySkip(TokenType.SYMBOL_COMMA)
+        );
+
+        var end = tokens.position();
+        var source = start.to(end);
+
+        return new UntypedArgsNode(positional, List.of(), source);
+    }
+
+    private static <T> List<T> parseMany(
+        BooleanSupplier stop,
+        Supplier<T> parseOne,
+        BooleanSupplier parseSeparator
+    ) {
+        var values = new ArrayList<T>();
+
+        while (!stop.getAsBoolean()) {
+            var value = parseOne.get();
+            values.add(value);
+            if (!parseSeparator.getAsBoolean()) {
+                return values;
+            }
+        }
+
+        return values;
     }
 
     private static UntypedExpressionNode parsePrimaryExpression(TokenIterator<TokenType> tokens) {
-- 
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