errp[1] = 1
        if(_is_null(hdlrs)) {
            _abort(_cdr(form), #_cons(_string("unhandled error"), _nil()),
                   env, d+1, hdlrs, st, errp)
        } else {
            # we have to get back to the (awk) frame where the handler
            # was added. there are checks for errp[1] in plenty of
            # places above that forestall further evaluation until the
            # handler kicks in.
            return _nil()
        }

        return _error(_cdr(form), env, d+1, hdlrs, st, errp)

function _error(errform, env, d, hdlrs, st, errp) {
    errp[1] = 1
    if(_is_null(hdlrs)) {
        _abort(errform, env, d, hdlrs, st, errp)
    } else {
        # we have to get back to the (awk) frame where the handler was
        # added. there are checks for errp[1] in plenty of places
        # above that forestall further evaluation until the handler
        # kicks in. since we are unwinding the (awk) stack, there is
        # no chance for the error to return anything: instead, the
        # (handle...) form will return the result of its handler.
        return _nil()
    }
}