From: Daniel Berger <Daniel.Berger@...>
Date: 2005-11-04T01:30:43+09:00
Subject: Question about NUM2LONG, symbols

Hi all,

The various NUM2x functions (NUM2LONG, NUM2INT, etc) include builtin type 
checks.  However, they still seem to blindly accept symbols.  Why?

/* foo.c */
#include "ruby.h"
#include <stdio.h>

static VALUE foo_test(VALUE self, VALUE num)
{
    long x;
    x = NUM2LONG(num);

    printf("NUM: %ld\n", x);

    return Qnil;
}

void Init_foo(){
    VALUE cFoo = rb_define_class("Foo", rb_cObject);
    rb_define_method(cFoo, "test", foo_test, 1);
}

# foo.rb
require "foo"

Foo.new.test("foo")        # TypeError, expected
Foo.new.test("foo".to_sym) # NUM: 10201 - yikes!

Regards,

Dan