Adding another matcher and moving a few things around.

src/prefix.c

@@ -163,6 +163,8 @@ static SEQUENCE_MATCHER(identstart, sass_prefix_is_optional_hyphen, sass_prefix_
 ONE_PLUS_MATCHER(name, sass_prefix_is_nmchar);
 FIRST_REST_MATCHER(identifier, sass_prefix_is_identstart, sass_prefix_is_nmchar);
 
+SEQUENCE_MATCHER(variable, sass_prefix_is_dollar, sass_prefix_is_identifier);
+
 static OPTIONAL_MATCHER(optional_digits, sass_prefix_is_digits);
 static SEQUENCE_MATCHER(realnum, sass_prefix_is_optional_digits, sass_prefix_is_dot, sass_prefix_is_digits);
 ALTERNATIVES_MATCHER(number, sass_prefix_is_digits, sass_prefix_is_realnum);
@@ -176,8 +178,4 @@ static OPTIONAL_MATCHER(optional_spaces, sass_prefix_is_spaces);
 SEQUENCE_MATCHER(adjacent_to, sass_prefix_is_optional_spaces, sass_prefix_is_plus);
 SEQUENCE_MATCHER(precedes, sass_prefix_is_optional_spaces, sass_prefix_is_tilde);
 SEQUENCE_MATCHER(parent_of, sass_prefix_is_optional_spaces, sass_prefix_is_gt);
-char *sass_prefix_is_ancestor_of(char *src) {
-  char *p = src;
+ALIAS_MATCHERS(sass_prefix_is_spaces, ancestor_of);
\ No newline at end of file
-  while (isspace(*p)) p++;
-  return p == src ? NULL : p;
-}
\ No newline at end of file

src/prefix.h

@@ -3,8 +3,11 @@ typedef char *(*sass_prefix_matcher)(char *);
 #define DECLARE(name) \
 char *sass_prefix_is_ ## name(char *)
 
+#define DECLARE_ALIAS(name) \
+sass_prefix_matcher sass_prefix_is_ ## name
+
 #define ALIAS_MATCHERS(orig, new) \
-char *(*new)(char *) = orig
+sass_prefix_matcher sass_prefix_is_ ## new = &orig
 
 #define CHAR_MATCHER(name, prefix) \
 char *sass_prefix_is_ ## name(char *src) { \
@@ -174,6 +177,8 @@ DECLARE(substringmatch);
 DECLARE(name);
 DECLARE(identifier);
 
+DECLARE(variable);
+
 DECLARE(number);
 DECLARE(string);
 
@@ -184,4 +189,5 @@ DECLARE(functional);
 DECLARE(adjacent_to);
 DECLARE(parent_of);
 DECLARE(precedes);
-DECLARE(ancestor_of);
+DECLARE_ALIAS(ancestor_of);
\ No newline at end of file
+

src/test_prefix.c

@@ -42,6 +42,8 @@ int main() {
   char *integer3 = "-294729+1";
   char *class = ".blah-blah_bloo112-blah+blee4 hello";
   char *id = "#foo_bar-baz123-hux blee";
+  char *var = "$blah123-blah";
+  char *non_var = "$ hux";
   
   test1(sass_prefix_is_spaces, spaces);
   test1(sass_prefix_is_spaces, words);
@@ -95,6 +97,9 @@ int main() {
   
   test1(sass_prefix_is_idname, id);
   test1(sass_prefix_is_idname, class);
+  
+  test1(sass_prefix_is_variable, var);
+  test1(sass_prefix_is_variable, non_var);
 
 
   return 0;