concat

/*
 * call-seq:
 *   concat(str)
 *   <<(str)
 *
 * Appends +str+ to the string being scanned.
 * This method does not affect scan pointer.
 *
 *   s = StringScanner.new("Fri Dec 12 1975 14:39")
 *   s.scan(/Fri /)
 *   s << " +1000 GMT"
 *   s.string            # -> "Fri Dec 12 1975 14:39 +1000 GMT"
 *   s.scan(/Dec/)       # -> "Dec"
 */
static VALUE
strscan_concat(VALUE self, VALUE str)
{
    struct strscanner *p;

    GET_SCANNER(self, p);
    StringValue(str);
    rb_str_append(p->str, str);
    return self;
}