Only allow positional args before named args

1 files changed, 32 insertions, 0 deletions

diff --git a/src/test/java/org/shedlang/compiler/parser/ParserCallTests.java b/src/test/java/org/shedlang/compiler/parser/ParserCallTests.java
index 1020b430..d75c6643 100644
--- a/src/test/java/org/shedlang/compiler/parser/ParserCallTests.java
+++ b/src/test/java/org/shedlang/compiler/parser/ParserCallTests.java
@@ -2,6 +2,7 @@ package org.shedlang.compiler.parser;
 
 import org.junit.jupiter.api.Test;
 
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.shedlang.compiler.ast.UntypedNodeMatchers.*;
 import static org.shedlang.compiler.parser.ParserTesting.parseString;
 import static org.zwobble.precisely.AssertThat.assertThat;
@@ -121,6 +122,37 @@ public class ParserCallTests {
     }
 
     @Test
+    public void canParseNamedArgumentAfterPositionalArgument() {
+        var source = "f(a, .named = b)";
+
+        var node = parseString(source, Parser::parseTopLevelExpression);
+
+        assertThat(
+            node,
+            isUntypedCallNode()
+                .withArgs(
+                    isUntypedArgsNode()
+                        .withPositional(isSequence(
+                            isUntypedReferenceNode("a")
+                        ))
+                        .withNamed(isSequence(
+                            isUntypedNamedArgNode("named", isUntypedReferenceNode("b"))
+                        ))
+                )
+        );
+    }
+
+    @Test
+    public void cannotParsePositionalArgumentAfterNamedArgument() {
+        var source = "f(.y = false, true)";
+
+        assertThrows(
+            PositionalArgAfterNamedArgError.class,
+            () -> parseString(source, Parser::parseTopLevelExpression)
+        );
+    }
+
+    @Test
     public void argumentListCanHaveTrailingComma() {
         var source = "f(a,)";