Added copy function

README.md

@@ -530,6 +530,16 @@ void mpc_cleanup(int n, ...);
 
 To ease the task of undefining and then deleting parsers `mpc_cleanup` can be used. It takes `n` parsers as input, and undefines them all, before deleting them all.
 
+* * *
+
+```c
+mpc_parser_t *mpc_copy(mpc_parser_t *a);
+```
+
+This function makes a copy of a parser `a`. This can be useful when you want to 
+use a parser as input for some other parsers multiple times without retaining 
+it. 
+
 
 Library Reference
 =================

mpc.c

@@ -1364,6 +1364,18 @@ mpc_parser_t *mpc_new(const char *name) {
   return p;
 }
 
+mpc_parser_t *mpc_copy(mpc_parser_t *a) {
+  mpc_parser_t *p = mpc_undefined();
+  p->retained = a->retained;
+  p->type = a->type;
+  p->data = a->data;
+  if (a->name) {
+    p->name = malloc(strlen(a->name)+1);
+    strcpy(p->name, a->name);
+  }
+  return p;
+}
+
 mpc_parser_t *mpc_undefine(mpc_parser_t *p) {
   mpc_undefine_unretained(p, 1);
   p->type = MPC_TYPE_UNDEFINED;

mpc.h

@@ -81,6 +81,7 @@ typedef mpc_val_t*(*mpc_fold_t)(int,mpc_val_t**);
 */
 
 mpc_parser_t *mpc_new(const char *name);
+mpc_parser_t *mpc_copy(mpc_parser_t *a);
 mpc_parser_t *mpc_define(mpc_parser_t *p, mpc_parser_t *a);
 mpc_parser_t *mpc_undefine(mpc_parser_t *p);