tryRun

tryRun is used to run parser with provided input, throwing ParserError on failure.

Usage

Success

tryRun(string('hello world')).with('hello world')

{
  isOk: true,
  start: 0,
  end: 11,
  pos: 11,
  value: 'hello world',
  errors: []
}

Failure

tryRun(string('hello world')).with('bye')

ParserError {
  name: 'ParserError',
  message: 'hello world',
  span: { start: 0, end: 3 },
  pos: 0,
  label: null,
  errors: []
}

ParserError sets name to ParserError and message to what the parser expected. It also carries span, pos, the label set by commit, and errors, which holds the failures the run recovered from. A run that failed outright is described by the error itself, and that failure isn't repeated in errors.

tryRun is the strict entry point, so it throws even when every failure was recovered by recover and run would have returned isOk: true. The error is then built from the first recovered failure, with errors holding them all.