default

/*
 *  call-seq:
 *     hsh.default(key=nil)   => obj
 *  
 *  Returns the default value, the value that would be returned by
 *  <i>hsh</i>[<i>key</i>] if <i>key</i> did not exist in <i>hsh</i>.
 *  See also <code>Hash::new</code> and <code>Hash#default=</code>.
 *     
 *     h = Hash.new                            #=> {}
 *     h.default                               #=> nil
 *     h.default(2)                            #=> nil
 *     
 *     h = Hash.new("cat")                     #=> {}
 *     h.default                               #=> "cat"
 *     h.default(2)                            #=> "cat"
 *     
 *     h = Hash.new {|h,k| h[k] = k.to_i*10}   #=> {}
 *     h.default                               #=> 0
 *     h.default(2)                            #=> 20
 */

static VALUE
rb_hash_default(argc, argv, hash)
    int argc;
    VALUE *argv;
    VALUE hash;
{
    VALUE key;

    rb_scan_args(argc, argv, "01", &key);
    if (FL_TEST(hash, HASH_PROC_DEFAULT)) {
        if (argc == 0) return Qnil;
        return rb_funcall(RHASH(hash)->ifnone, id_call, 2, hash, key);
    }
    return RHASH(hash)->ifnone;
}