Basic combinators for tokenizing. Unfortunately, I can't use va_args because it…

Basic combinators for tokenizing. Unfortunately, I can't use va_args because it can't handle the signatures of function pointers.

src/parser/prefix_primitives.c

 #include <ctype.h>
 #include <string.h>
 #include <stdio.h>
+#include <stdarg.h>
 #include "prefix_primitives.h"
 
 int prefix_is_exactly(char *src, char* pre) {
@@ -33,6 +34,12 @@ int prefix_is_delimited_by(char *src, char *beg, char *end, int esc) {
   }
 }
 
+int prefix_try_alternatives(char *src, int (*m[])(char *)) {
+  int p = 0;
+  while (m && !(p = (*m)(src))) m++;
+  return p;
+}
+
 DEFINE_SINGLE_CTYPE_MATCHER(space);
 DEFINE_SINGLE_CTYPE_MATCHER(alpha);
 DEFINE_SINGLE_CTYPE_MATCHER(digit);
@@ -52,8 +59,12 @@ DEFINE_DELIMITED_MATCHER(single_quoted_string, "'", "'", 1);
 DEFINE_DELIMITED_MATCHER(interpolant, "#{", "}", 0);
 
 int prefix_is_string(char *src) {
-  int len = prefix_is_double_quoted_string(src);
-  return len ? len : prefix_is_single_quoted_string(src);
+  int (*ms[])(char *) = {
+    prefix_is_double_quoted_string,
+    prefix_is_single_quoted_string,
+    NULL
+  };
+  return prefix_try_alternatives(src, ms);
 }
 
 DEFINE_EXACT_MATCHER(lparen, "(");

src/parser/test.c

@@ -16,14 +16,16 @@ void printn(char *s, int n) {
 
 int main() {
   char *s = "'this \\'is\\' a \"string\" now' blah blah blah";
-  char *t = "/* this is a c comment \\x */ blah blah";
-  char *u = "#{ this is an interpolant \\x } blah blah";
+  char *t = "/* this is a c comment \\*/ blah blah";
+  char *u = "#{ this is an interpolant \\} blah blah";
   char *v = "hello my name is aaron";
+  
+  int (*funcs[])(char *) = { prefix_is_string, prefix_is_block_comment, NULL };
 
-  printn(s, prefix_is_string(s));
+  printn(s, funcs[0](s));
   printn(s, prefix_is_one_of(s, "abcde+'"));
   printn(s, prefix_is_some_of(s, "'abcdefghijklmnopqrstuvwxyz "));
-  printn(t, prefix_is_block_comment(t));
+  printn(t, funcs[1](t));
   printn(u, prefix_is_interpolant(u));
   printn(v, prefix_is_alphas(v));
   printn(v, prefix_is_one_alpha(v));