parse_trans/README.md

#The parse_trans application#

Authors: Ulf Wiger (ulf@feuerlabs.com).

A generic parse transform library This library is intended to simplify the task of writing parse transform modules for Erlang.

#Introduction to parse transforms#

##The simplest transform##

The very simplest transform we can make is one that doesn't change a thing. For convenience, we will at least print the forms. This will enlighten us as to what the forms actually look like.

-module(test_pt).

-export([parse_transform/2]).
parse_transform(Forms, _Options) ->
io:fwrite("Forms = ~p~n", [Forms]),
Forms.

Trying this with a very simple module:

-module(ex1).
-export([add/2]).

add(X,Y) ->
X + Y.

1> c(ex1, [{parse_transform,test_pt}]).
Forms = [{attribute,1,file,{"./ex1.erl",1}},
{attribute,1,module,ex1},
{attribute,2,export,[{add,2}]},
{function,4,add,2,
[{clause,4,
[{var,4,'X'},{var,4,'Y'}],
[],
[{op,5,'+',{var,5,'X'},{var,5,'Y'}}]}]},
{eof,6}]
{ok,ex1}

##transform/4##

...

#Current limitations#

...

##Modules##

ct_expand

exprecs

parse_trans

parse_trans_codegen

parse_trans_mod

parse_trans_pp