Extend rb_scan_args to get keyword arguments

gistfile1.diff

diff --git a/array.c b/array.c
index 9a93d7f..b673c63 100644
--- a/array.c
+++ b/array.c
@@ -4429,7 +4429,7 @@ static VALUE sym_random;
 static VALUE
 rb_ary_shuffle_bang(int argc, VALUE *argv, VALUE ary)
 {
-    VALUE opts, randgen = rb_cRandom;
+    VALUE rnd, randgen = rb_cRandom;
     long i, len;
     static ID keyword_ids[1];
 
@@ -4437,14 +4437,10 @@ rb_ary_shuffle_bang(int argc, VALUE *argv, VALUE ary)
 	keyword_ids[0] = rb_intern("random");
     }
 
-    if (OPTHASH_GIVEN_P(opts)) {
-	VALUE rnd;
-	rb_get_kwargs(opts, keyword_ids, 0, 1, &rnd);
-	if (rnd != Qundef) {
-	    randgen = rnd;
-	}
+    rb_scan_args(argc, argv, "00:01", NULL, keyword_ids, &rnd);
+    if (rnd != Qundef) {
+	randgen = rnd;
     }
-    rb_check_arity(argc, 0, 0);
     rb_ary_modify(ary);
     i = len = RARRAY_LEN(ary);
     RARRAY_PTR_USE(ary, ptr, {
diff --git a/class.c b/class.c
index 66495eb..c13f4b3 100644
--- a/class.c
+++ b/class.c
@@ -1727,8 +1727,9 @@ rb_scan_args(int argc, const VALUE *argv, const char *fmt, ...)
     const char *p = fmt;
     VALUE *var;
     va_list vargs;
-    int f_var = 0, f_hash = 0, f_block = 0;
+    int f_var = 0, f_hash = 0, f_get_kwargs = 0, f_block = 0;
     int n_lead = 0, n_opt = 0, n_trail = 0, n_mand;
+    int n_keyword_required = 0, n_keyword_optional = 0;
     int argi = 0;
     VALUE hash = Qnil;
 
@@ -1757,6 +1758,18 @@ rb_scan_args(int argc, const VALUE *argv, const char *fmt, ...)
     if (*p == ':') {
 	f_hash = 1;
 	p++;
+	if (ISDIGIT(*p)) {
+	    f_get_kwargs = 1;
+	    n_keyword_required = *p - '0';
+	    p++;
+	    if (ISDIGIT(*p)) {
+		n_keyword_optional = *p - '0';
+		p++;
+	    }
+	    else {
+		rb_fatal("bad scan arg format: %s", fmt);
+	    }
+	}
     }
     if (*p == '&') {
 	f_block = 1;
@@ -1831,6 +1844,11 @@ rb_scan_args(int argc, const VALUE *argv, const char *fmt, ...)
     /* capture an option hash - phase 2: assignment */
     if (f_hash) {
 	var = va_arg(vargs, VALUE *);
+	if (f_get_kwargs) {
+	    ID *ids = va_arg(vargs, ID *);
+	    VALUE *values = va_arg(vargs, VALUE *);
+	    rb_get_kwargs(NIL_P(hash) ? 0 : hash, ids, n_keyword_required, n_keyword_optional, values);
+	}
 	if (var) *var = hash;
     }
     /* capture iterator block */