You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 

987 B

tracer#trace()

Whether you are using the CLI or the API, as long as you pass the trace option, the generated parser can trace it's progress by calling tracer.trace( event ), which can then be overwritten by passing an alternative tracer in the options to the generated parser.

You can also optionally disable the default tracer by passing features: { DefaultTracer: false } to peg.generate or peg.compiler.compile, in which case a empry function will be called by default unless a tracer is passed to the parser.

The event passed to the trace method contains the following properties:

property description
type name of the event
rule rule that this event was emitted from
result the result of the match
location location in the grammar when the event was emitted

The type property will only be 1 of 3 values:

  1. rule.enter when entering a rule
  2. rule.match when matching a rule was successful
  3. rule.fail when matching a rule failed