Add mpc_checkf and mpc_check_withf combinators.

README.md

@@ -314,6 +314,8 @@ Returns a parser that applies function `f` (optionality taking extra input `x`)
 ```c
 mpc_parser_t *mpc_check(mpc_parser_t *a, mpc_check_t f, const char *e);
 mpc_parser_t *mpc_check_with(mpc_parser_t *a, mpc_check_with_t f, void *x, const char *e);
+mpc_parser_t *mpc_checkf(mpc_parser_t *a, mpc_check_t f, const char *fmt, ...);
+mpc_parser_t *mpc_check_withf(mpc_parser_t *a, mpc_check_with_t f, void *x, const char *fmt, ...);
 ```
 
 Returns a parser that applies function `f` (optionally taking extra input `x`) to the result of parser `a`. If `f` returns non-zero, then the parser succeeds and returns the value of `a` (possibly modified by `f`). If `f` returns zero, then the parser fails with message `e`.

mpc.c

@@ -1790,6 +1790,38 @@ mpc_parser_t *mpc_check_with(mpc_parser_t *a, mpc_check_with_t f, void *x, const
   return p;
 }
 
+mpc_parser_t *mpc_checkf(mpc_parser_t *a, mpc_check_t f, const char *fmt, ...) {
+  va_list        va;
+  char          *buffer;
+  mpc_parser_t  *p;
+
+  va_start(va, fmt);
+  buffer = malloc(2048);
+  vsprintf(buffer, fmt, va);
+  va_end(va);
+
+  p = mpc_check (a, f, buffer);
+  free (buffer);
+
+  return p;
+}
+
+mpc_parser_t *mpc_check_withf(mpc_parser_t *a, mpc_check_with_t f, void *x, const char *fmt, ...) {
+  va_list        va;
+  char          *buffer;
+  mpc_parser_t  *p;
+
+  va_start(va, fmt);
+  buffer = malloc(2048);
+  vsprintf(buffer, fmt, va);
+  va_end(va);
+
+  p = mpc_check_with (a, f, x, buffer);
+  free (buffer);
+
+  return p;
+}
+
 mpc_parser_t *mpc_predictive(mpc_parser_t *a) {
   mpc_parser_t *p = mpc_undefined();
   p->type = MPC_TYPE_PREDICT;

mpc.h

@@ -130,6 +130,8 @@ mpc_parser_t *mpc_apply(mpc_parser_t *a, mpc_apply_t f);
 mpc_parser_t *mpc_apply_to(mpc_parser_t *a, mpc_apply_to_t f, void *x);
 mpc_parser_t *mpc_check(mpc_parser_t *a, mpc_check_t f, const char *e);
 mpc_parser_t *mpc_check_with(mpc_parser_t *a, mpc_check_with_t f, void *x, const char *e);
+mpc_parser_t *mpc_checkf(mpc_parser_t *a, mpc_check_t f, const char *fmt, ...);
+mpc_parser_t *mpc_check_withf(mpc_parser_t *a, mpc_check_with_t f, void *x, const char *fmt, ...);
 
 mpc_parser_t *mpc_not(mpc_parser_t *a, mpc_dtor_t da);
 mpc_parser_t *mpc_not_lift(mpc_parser_t *a, mpc_dtor_t da, mpc_ctor_t lf);

tests/combinators.c

@@ -45,6 +45,42 @@ void test_check_with(void) {
   mpc_delete(p);
 }
 
+void test_checkf(void) {
+  int           success;
+  mpc_result_t  r;
+  mpc_parser_t* p = mpc_checkf(mpc_or(2, mpc_char('a'), mpc_char('b')), check_is_a, "Expected '%s'", "a");
+
+  success = mpc_parse("test", "a", p, &r);
+  PT_ASSERT(success);
+  PT_ASSERT_STR_EQ(r.output, "a");
+  if (success) free(r.output); else mpc_err_delete(r.error);
+
+  success = mpc_parse("test", "b", p, &r);
+  PT_ASSERT(!success);
+  PT_ASSERT_STR_EQ(r.error->failure, "Expected 'a'");
+  if (success) free(r.output); else mpc_err_delete(r.error);
+
+  mpc_delete(p);
+}
+
+void test_check_withf(void) {
+  int           success;
+  mpc_result_t  r;
+  mpc_parser_t* p = mpc_check_withf(mpc_or(2, mpc_char('a'), mpc_char('b')), check_is, "a", "Expected '%s'", "a");
+
+  success = mpc_parse("test", "a", p, &r);
+  PT_ASSERT(success);
+  if (success) PT_ASSERT_STR_EQ(r.output, "a");
+  if (success) free(r.output); else mpc_err_delete(r.error);
+
+  success = mpc_parse("test", "b", p, &r);
+  PT_ASSERT(!success);
+  if (!success) PT_ASSERT_STR_EQ(r.error->failure, "Expected 'a'");
+  if (success) free(r.output); else mpc_err_delete(r.error);
+
+  mpc_delete(p);
+}
+
 void suite_combinators(void) {
   pt_add_test(test_check,      "Test Check",      "Suite Combinators");
   pt_add_test(test_check_with, "Test Check with", "Suite Combinators");