path: root/lib/stdlib/doc/src/erl_id_trans.xml

<?xml version="1.0" encoding="latin1" ?>
<!DOCTYPE erlref SYSTEM "erlref.dtd">

<erlref>
  <header>
    <copyright>
      <year>1996</year>
      <year>2011</year>
      <holder>Ericsson AB, All Rights Reserved</holder>
    </copyright>
    <legalnotice>
  The contents of this file are subject to the Erlang Public License,
  Version 1.1, (the "License"); you may not use this file except in
  compliance with the License. You should have received a copy of the
  Erlang Public License along with this software. If not, it can be
  retrieved online at http://www.erlang.org/.

  Software distributed under the License is distributed on an "AS IS"
  basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
  the License for the specific language governing rights and limitations
  under the License.

  The Initial Developer of the Original Code is Ericsson AB.
    </legalnotice>

    <title>erl_id_trans</title>
    <prepared>Robert Virding</prepared>
    <responsible>Bjarne D&auml;cker</responsible>
    <docno>1</docno>
    <approved>Bjarne D&auml;cker</approved>
    <checked></checked>
    <date>97-01-21</date>
    <rev>B</rev>
    <file>erl_id_trans.sgml</file>
  </header>
  <module>erl_id_trans</module>
  <modulesummary>An Identity Parse Transform</modulesummary>
  <description>
    <p>This module performs an identity parse transformation of Erlang code.
      It is included as an example for users who may wish to write their own
      parse transformers. If the option <c>{parse_transform,Module}</c> is passed
      to the compiler, a user written function <c>parse_transform/2</c>
      is called by the compiler before the code is checked for
      errors.</p>
  </description>
  <funcs>
    <func>
      <name>parse_transform(Forms, Options) -> Forms</name>
      <fsummary>Transform Erlang forms</fsummary>
      <type>
        <v>Forms = [<seealso marker="erl_parse#type-abstract_form">erl_parse:abstract_form()</seealso>]</v>
        <v>Options = [<seealso marker="compile#type-option">compile:option()</seealso>]</v>
      </type>
      <desc>
        <p>Performs an identity transformation on Erlang forms, as an example.</p>
      </desc>
    </func>
  </funcs>

  <section>
    <title>Parse Transformations</title>
    <p>Parse transformations are used if a programmer wants to use
      Erlang syntax, but with different semantics. The original Erlang
      code is then transformed into other Erlang code.
      </p>
    <note>
      <p>Programmers are strongly advised not to engage in parse transformations and no support is offered for problems encountered.</p>
    </note>
  </section>

  <section>
    <title>See Also</title>
    <p><seealso marker="erl_parse">erl_parse(3)</seealso>,
    <seealso marker="compiler:compile">compile(3)</seealso>.</p>
  </section>
</erlref>