native implementatino of for-each

src/proc.c

@@ -126,10 +126,39 @@ pic_proc_map(pic_state *pic)
   return pic_reverse(pic, ret);
 }
 
+static pic_value
+pic_proc_for_each(pic_state *pic)
+{
+  struct pic_proc *proc;
+  size_t argc;
+  pic_value *args;
+  int i;
+  pic_value cars;
+
+  pic_get_args(pic, "l*", &proc, &argc, &args);
+
+  do {
+    cars = pic_nil_value();
+    for (i = argc - 1; i >= 0; --i) {
+      if (! pic_pair_p(args[i])) {
+        break;
+      }
+      cars = pic_cons(pic, pic_car(pic, args[i]), cars);
+      args[i] = pic_cdr(pic, args[i]);
+    }
+    if (i >= 0)
+      break;
+    pic_apply(pic, proc, cars);
+  } while (1);
+
+  return pic_none_value();
+}
+
 void
 pic_init_proc(pic_state *pic)
 {
   pic_defun(pic, "procedure?", pic_proc_proc_p);
   pic_defun(pic, "apply", pic_proc_apply);
   pic_defun(pic, "map", pic_proc_map);
+  pic_defun(pic, "for-each", pic_proc_for_each);
 }