assertEquals(value,
TerminalParser.parse(parser, source.substring(0, source.length() - rest.length())));
}
static void assertOperator(Parser<?> parser, String source) {
Token actual = (Token) TerminalParser.parse(parser, source);
assertEquals(0, actual.index());
assertEquals(source.length(), actual.length());
// TODO: do we make adjacent() call Tokens.reserved()?
// That seems verbose unless we make Tokenizers public.
assertEquals(source, actual.value().toString());
}