ReferenceError: head is not defined

Hello & thank you for your work on peggy and for picking up where pegjs left off.

I’m one of the maintainers of amqplib and investigating https://github.com/amqp-node/amqplib/issues/453. amqplib uses pegjs via bitsyntax to generate a parser from the grammar specified here.

bitsyntax’s last working parser was generated using pegjs@0.7.0 and upgrading to pegjs@0.1.0, peggy@^1.0.0 or peggy@latest results in a broken parser.

/Users/steve/Development/squaremo/bitsyntax-js/lib/parser.js:256
  var peg$f17 = function() { return head + tail.join(''); };
                             ^

ReferenceError: head is not defined

I’m completely new to pegjs/peggy and was hoping it’s an easy fix. Can you give me any pointers please?

Thanks

[Mingun]

Actually, your original grammar worked because of a bug, fixed in pegjs@0.10.0:

Fixed label scoping so that labels in expressions like (a:"a") or (a:"a" b:"b" c:"c") aren’t visible from the outside.

Also, you could simplify your grammar much more using a new @ operator, for example, here:

segmentTail
    = ws ',' ws @segment

and using a $ operator instead of return text():

identifier
    = $([_a-zA-Z] [_a-zA-Z0-9]*)

[hildjj]

Let us know if you’d like more help with the grammar. Happy to pitch in as needed.