parse_trans/doc

The parse_trans application

The parse_trans application

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

Authors: Ulf Wiger (ulf.wiger@erlang-consulting.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`

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Current limitations

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Modules

ct_expand

exprecs

parse_trans

parse_trans_codegen

parse_trans_pp