From: Nick Bowler <nbowler@draconx.ca>
Date: Thu, 20 Jul 2023 00:28:59 +0000 (-0400)
Subject: libcdecl: Factor out open-coded list concatenation.
X-Git-Tag: v1.3~111
X-Git-Url: https://git.draconx.ca/gitweb/cdecl99.git/commitdiff_plain/032fe50c0297846a8d03eda505c9726f60a46501

libcdecl: Factor out open-coded list concatenation.

The parser has two rules which join two lists.  Let's add a helper
to do that instead of duplicating the code for list concatenation.
Furthermore, in both cases one of the lists is known to be nonempty;
the implementation can be slightly simplified with that assumption.
---

diff --git a/src/parse.y b/src/parse.y
index abfccd2..cf24b25 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -142,6 +142,19 @@ void cdecl__free(struct cdecl *decl)
 {
 	free_decl(decl);
 }
+
+/*
+ * Join two declaration specifier lists into a single list, with "a" being the
+ * head of the new list.
+ *
+ * The list "a" is assumed to be nonempty.
+ */
+static void join_specs(struct cdecl_declspec *a, struct cdecl_declspec *b)
+{
+	while (a->next)
+		a = a->next;
+	a->next = b;
+}
 %}
 
 %destructor { free($$); }            <strval>
@@ -467,27 +480,16 @@ type_qual_specs: { $$ = NULL; } | type_qual_spec type_qual_specs {
  * together three different specifiers lists.
  */
 post_specs: qualifiers typespec type_qual_specs {
+	$2->next = $3;
+	join_specs($2, $1);
 	$$ = $2;
-	$$->next = $1;
-	for (struct cdecl_declspec *s = $$; s; s = s->next) {
-		if (!s->next) {
-			s->next = $3;
-			break;
-		}
-	}
 }
 
 english_declaration: storage_func_specs english_declarator post_specs {
+	join_specs($3, $1);
 	ALLOC_STRUCT($$, struct cdecl,
 		.specifiers = $3,
 		.declarators = $2);
-
-	for (struct cdecl_declspec *s = $$->specifiers; s; s = s->next) {
-		if (!s->next) {
-			s->next = $1;
-			break;
-		}
-	}
 }
 
 english_declarator: {