Require consistency in positionality of struct fields

2 files changed, 16 insertions, 0 deletions

diff --git a/src/main/java/org/shedlang/compiler/parser/Parser.java b/src/main/java/org/shedlang/compiler/parser/Parser.java
index faf75600..2f6256d9 100644
--- a/src/main/java/org/shedlang/compiler/parser/Parser.java
+++ b/src/main/java/org/shedlang/compiler/parser/Parser.java
@@ -997,6 +997,12 @@ public class Parser {
         );
         tokens.skip(TokenType.SYMBOL_PAREN_CLOSE);
 
+        var anyPositionalFields = fields.stream().anyMatch(field -> field.isPositional());
+        var anyNonPositionalFields = fields.stream().anyMatch(field -> !field.isPositional());
+        if (anyPositionalFields && anyNonPositionalFields) {
+            throw new InconsistentStructFieldsError(fields.get(0).source());
+        }
+
         tokens.skip(TokenType.SYMBOL_BRACE_OPEN);
         tokens.skip(TokenType.SYMBOL_BRACE_CLOSE);
 
diff --git a/src/main/java/org/shedlang/compiler/parser/errors/InconsistentStructFieldsError.java b/src/main/java/org/shedlang/compiler/parser/errors/InconsistentStructFieldsError.java
new file mode 100644
index 00000000..d3dfc03c
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/parser/errors/InconsistentStructFieldsError.java
@@ -0,0 +1,10 @@
+package org.shedlang.compiler.parser.errors;
+
+import org.shedlang.compiler.errors.SourceError;
+import org.shedlang.compiler.sources.Source;
+
+public class InconsistentStructFieldsError extends SourceError {
+    public InconsistentStructFieldsError(Source source) {
+        super("all struct fields must either be positional or non-positional", source);
+    }
+}