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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 yourself, we recommend you fork it.
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lex-pass allows you to automate changes to a php codebase, by writing
abstract-syntax-tree transformers in haskell. haskell is good because it is
well-suited for language manipulation and because it has good parsing libraries
that enable us to work with a nice abstract-syntax-tree.
to install
- ./install
depends on
- futil (git://
to use
- run `lex-pass` to see options
- to see an example run, run `lex-pass example-global` with a codebase in
~/www that uses some globals (e.g. "global $a;")
- note a large codebase could takes tens of minutes the first run because no
ast's are cached yet
- you can ^C it early after it does 'Saving' on a few files to see how the
changes work
- to write a new transformer
- see src/Transf/ for examples
- src/do-codegen (which is run by ./install) automatically detects new
transformers in src/Transf/
- if you are using git you may want to use a separate repo instead of just a
branch in an existing repo. files have mtime updated by branch-switching,
so there will be some unnecessary re-parsing.
notes for those hacking on lex-pass itself
- todo
- php: b'' type string literals
- maintain cached asts for codebase somewhere so ppl don't have to wait on
their first lex-pass run?
- better error on one-arg transf's if args wrong?
- better way to specify args in transf doc?
- make showing full transf list an option instead of default help?
- we might actually get better perf with our own lexer, or at least not
restarting php over and over again to do lexing. but not worth looking
into any time soon?
- resolve xWs/xWS, xAst/xAST variable-capitalization indecision
- future langs
- css - easy and relevant, but maybe a css-preprocessor is better to use
- js - relevant
- bash (we should probably just stop using..), c, python