Update `mrb_get_args()` keyword argument support [incompatible]

* `mrb_kwargs` structure reordered (`values` and `rest` come last)
* take symbols instead of C `char*`

include/mruby.h

@@ -929,7 +929,7 @@ typedef const char *mrb_args_format;
  *      const char *kw_names[kw_num] = { "a", "b" };
  *      uint32_t kw_required = 0;
  *      mrb_value kw_values[kw_num];
- *      const mrb_kwargs kwargs = { kw_num, kw_values, kw_names, kw_required, NULL };
+ *      const mrb_kwargs kwargs = { kw_num, kw_required, kw_names, kw_values, NULL };
  *
  *      mrb_get_args(mrb, ":", &kwargs);
  *      if (mrb_undef_p(kw_values[0])) { kw_values[0] = mrb_fixnum_value(1); }
@@ -940,10 +940,10 @@ typedef const char *mrb_args_format;
  *
  *      mrb_value str, kw_rest;
  *      uint32_t kw_num = 3;
- *      const char *kw_names[kw_num] = { "x", "y", "z" };
+ *      const mrb_sym kw_names[kw_num] = { MRB_SYM(x), MRB_SYM(y), MRB_SYM(z) };
  *      uint32_t kw_required = 1;
  *      mrb_value kw_values[kw_num];
- *      const mrb_kwargs kwargs = { kw_num, kw_values, kw_names, kw_required, &kw_rest };
+ *      const mrb_kwargs kwargs = { kw_num, kw_required, kw_names, kw_values, &kw_rest };
  *
  *      mrb_get_args(mrb, "S:", &str, &kwargs);
  *      // or: mrb_get_args(mrb, ":S", &kwargs, &str);
@@ -954,11 +954,11 @@ typedef struct mrb_kwargs mrb_kwargs;
 
 struct mrb_kwargs
 {
-  uint32_t num;
-  mrb_value *values;
-  const char *const *table;
-  uint32_t required;
-  mrb_value *rest;
+  uint32_t num;                 /* number of keyword arguments */
+  uint32_t required;            /* number of required keyword arguments */
+  mrb_sym *table;               /* C array of symbols for keyword names */
+  mrb_value *values;            /* keyword argument values */
+  mrb_value *rest;              /* keyword rest (dict) */
 };
 
 /**

src/class.c

@@ -1254,7 +1254,7 @@ mrb_get_args(mrb_state *mrb, const char *format, ...)
         else {
           uint32_t kwnum = kwargs->num;
           uint32_t required = kwargs->required;
-          const char *const *kname = kwargs->table;
+          const mrb_sym *kname = kwargs->table;
           mrb_value *values = kwargs->values;
           uint32_t j;
           const uint32_t keyword_max = 40;
@@ -1264,16 +1264,16 @@ mrb_get_args(mrb_state *mrb, const char *format, ...)
           }
 
           for (j = required; j > 0; j --, kname ++, values ++) {
-            mrb_value k = mrb_symbol_value(mrb_intern_cstr(mrb, *kname));
+            mrb_value k = mrb_symbol_value(*kname);
             if (!mrb_hash_key_p(mrb, ksrc, k)) {
-              mrb_raisef(mrb, E_ARGUMENT_ERROR, "missing keyword: %s", *kname);
+              mrb_raisef(mrb, E_ARGUMENT_ERROR, "missing keyword: %n", *kname);
             }
             *values = mrb_hash_delete_key(mrb, ksrc, k);
             mrb_gc_protect(mrb, *values);
           }
 
           for (j = kwnum - required; j > 0; j --, kname ++, values ++) {
-            mrb_value k = mrb_symbol_value(mrb_intern_cstr(mrb, *kname));
+            mrb_value k = mrb_symbol_value(*kname);
             if (mrb_hash_key_p(mrb, ksrc, k)) {
               *values = mrb_hash_delete_key(mrb, ksrc, k);
               mrb_gc_protect(mrb, *values);