/*
 * call-seq: check(pattern)
 *
 * This returns the value that #scan would return, without advancing the scan
 * pointer.  The match register is affected, though.
 *
 *   s = StringScanner.new("Fri Dec 12 1975 14:39")
 *   s.check /Fri/               # -> "Fri"
 *   s.pos                       # -> 0
 *   s.matched                   # -> "Fri"
 *   s.check /12/                # -> nil
 *   s.matched                   # -> nil
 *
 * Mnemonic: it "checks" to see whether a #scan will return a value.
 */
static VALUE
strscan_check(self, re)
    VALUE self, re;
{
    return strscan_do_scan(self, re, 0, 1, 1);
}