not method
Returns a parser (logical not-predicate) that succeeds with the Failure whenever the receiver fails, but never consumes input.
For example, the parser char('_').not().seq(identifier)
accepts
identifiers that do not start with an underscore character. If the parser
char('_')
accepts the input, the negation and subsequently the
complete parser fails. Otherwise the parser identifier
is given the
ability to process the complete identifier.
Implementation
@useResult
Parser<Failure> not([String message = 'success not expected']) =>
NotParser(this, message);