chop

/*
 *  call-seq:
 *     chop   => string
 *  
 *  Equivalent to <code>($_.dup).chop!</code>, except <code>nil</code>
 *  is never returned. See <code>String#chop!</code>.
 *     
 *     a  =  "now\r\n"
 *     $_ = a
 *     chop   #=> "now"
 *     $_     #=> "now"
 *     chop   #=> "no"
 *     chop   #=> "n"
 *     chop   #=> ""
 *     chop   #=> ""
 *     a      #=> "now\r\n"
 */

static VALUE
rb_f_chop()
{
    VALUE str = uscore_get();

    if (RSTRING(str)->len > 0) {
        str = rb_str_dup(str);
        rb_str_chop_bang(str);
        rb_lastline_set(str);
    }
    return str;
}