/libfbjs

JavaScript parser and AST manipulation framework

Primary LanguageC++Apache License 2.0Apache-2.0

Archived Repo
=============
This is an archived project and is no longer supported or updated by Facebook. 
Please do not file issues or pull-requests against this repo. If you wish to 
continue to develop this code, we recommend you fork it.

Proceed and be bold!

== Building ==
It's recommended that you build this software with the latest versions of flex
and bison.

You can download flex here:
http://flex.sourceforge.net/

And bison here:
http://www.gnu.org/software/bison/

This software was developed using flex version 2.5.35 and bison version 2.3.
Please note that flex 2.5.4 is OLDER than 2.5.35, and will not be able to build
this software.

To build simply execute `make fbjs`. You can ignore the sign warning in
`yy_get_next_buffer`; I'm pretty sure that's a bug in flex and not in libfbjs.


== How to use ==
To apply the FBJS2 transformations to a program `make fbjs` and pipe a program
to `fbjs`. In cli.cpp you'll find the code needed to invoke this transformation.

To use the FBJS2 parser in other software you may want to check out
jsbeautify.cpp. Documentation is paltry, but it should be pretty easy to get up
to speed if you have a familiarity of Javascript and C++.


== Notes ==
* NodeString expressions are implemented poorly right now. Instead of parsing
  what's in the string we just grab the raw contents from code. This was just
  a hack because I didn't feel like writing the state machine to convert \x,
  \u, \0, etc into bytes.
* There will be a memory leak when you attempt to parse a program with a syntax
  error in it. This is because the authority of freeing allocated nodes is left
  to the parent node. The problem is that the allocated child nodes aren't added
  to the AST until the very last reduciton. Thus, when a ParseException is
  raised the allocated nodes are lost since they never became associated with a
  managed node.
* Handling of virtual semicolons is probably not to spec.