From 2f5dfe381ea7156b1e537e487281d059009228e8 Mon Sep 17 00:00:00 2001
From: Lorenzo Torres <lorenzo@sagittarius-a.org>
Date: Thu, 4 Dec 2025 22:41:18 +0100
Subject: [PATCH] implemented cycling definition checking

---
 examples/hello_world.l | 12 ++++++------
 sema.c                 | 15 ++++++++++++---
 2 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/examples/hello_world.l b/examples/hello_world.l
index 8663534..61cebe9 100644
--- a/examples/hello_world.l
+++ b/examples/hello_world.l
@@ -1,11 +1,11 @@
+struct a {
+	b hello,
+}
+
 struct b {
-	a ciao,
+	c ciao,
 }
 
 struct c {
-	u32 test,
-}
-
-struct a {
-	c hello,
+	b test,
 }
diff --git a/sema.c b/sema.c
index e3eb84a..18aac86 100644
--- a/sema.c
+++ b/sema.c
@@ -20,7 +20,11 @@ static struct { char *key; type *value; } *type_reg;
 /* Print the error message and sync the parser. */
 static void error(ast_node *n, char *msg)
 {
-	printf("\x1b[31m\x1b[1merror\x1b[0m\x1b[1m:%ld:%ld:\x1b[0m %s\n", n->position.row, n->position.column, msg);
+	if (n) {
+		printf("\x1b[31m\x1b[1merror\x1b[0m\x1b[1m:%ld:%ld:\x1b[0m %s\n", n->position.row, n->position.column, msg);
+	} else {
+		printf("\x1b[31m\x1b[1merror\x1b[0m\x1b[1m:\x1b[0m %s\n", msg);
+	}
 }
 
 static char *intern_string(sema *s, char *str, usize len)
@@ -180,7 +184,8 @@ end:
 
 	res_node **nodes = NULL;
 	res_node **ordered = NULL;
-	for (int i=0; i < shlen(types); i++) {
+	usize node_count = shlen(types);
+	for (int i=0; i < node_count; i++) {
 		if (arrlen(types[i].value->node.in) == 0) {
 			arrput(nodes, &types[i].value->node);
 		}
@@ -206,10 +211,14 @@ end:
 		}
 	}
 
+	if (arrlen(ordered) != node_count) {
+		error(NULL, "cycling struct definition.");
+	}
+
 	for (int i=0; i < arrlen(ordered); i++) {
 		type *t = ordered[i]->value;
 		if (t && (t->tag == TYPE_STRUCT || t->tag == TYPE_UNION)) {
-			char *name = intern_string(s, t->data.structure.name, t->data.structure.name_len);
+			char *name = t->name;
 			printf("%s\n", name);
 			register_type(s, name, t);
 		}