stdlib: Add module erl_anno

Introduce erl_anno, an abstraction of the second element of tokens and
tuples in the abstract format. The convention that negative line
numbers can be used for silencing compiler warnings will no longer
work in OTP 19; instead the annotation 'generated' is to be used.

1 files changed, 308 insertions, 0 deletions

diff --git a/lib/stdlib/doc/src/erl_anno.xml b/lib/stdlib/doc/src/erl_anno.xml
new file mode 100644
index 0000000000..281feacdc4
--- /dev/null
+++ b/lib/stdlib/doc/src/erl_anno.xml
@@ -0,0 +1,308 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<!DOCTYPE erlref SYSTEM "erlref.dtd">
+
+<erlref>
+  <header>
+    <copyright>
+      <year>2015</year>
+      <year>2015</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 on line 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_anno</title>
+    <prepared>Hans Bolinder</prepared>
+    <responsible>Kenneth Lundin</responsible>
+    <docno>1</docno>
+    <approved></approved>
+    <checked></checked>
+    <date>2015-02-26</date>
+    <rev>A</rev>
+    <file>erl_anno.xml</file>
+  </header>
+  <module>erl_anno</module>
+
+  <modulesummary>
+    Abstract Datatype for the Annotations of the Erlang Compiler
+  </modulesummary>
+
+  <description>
+    <p>This module implements an abstract type that is used by the
+      Erlang Compiler and its helper modules for holding data such as
+      column, line number, and text. The data type is a collection of
+      <marker id="annotations"><em>annotations</em></marker> as
+      described in the following.</p>
+    <p>The Erlang Token Scanner returns tokens with a subset of
+      the following annotations, depending on the options:</p>
+    <taglist>
+      <tag><c>column</c></tag>
+      <item><p>The column where the token begins.</p></item>
+      <tag><c>location</c></tag>
+      <item><p>The line and column where the token begins, or
+        just the line if the column unknown.</p>
+      </item>
+      <tag><c>text</c></tag>
+      <item><p>The token's text.</p></item>
+    </taglist>
+    <p>From the above the following annotation is derived:</p>
+    <taglist>
+      <tag><c>line</c></tag>
+      <item><p>The line where the token begins.</p></item>
+    </taglist>
+    <p>Furthermore, the following annotations are supported by
+      this module, and used by various modules:</p>
+    <taglist>
+      <tag><c>file</c></tag>
+      <item><p>A filename.</p></item>
+      <tag><c>generated</c></tag>
+      <item><p>A Boolean indicating if the abstract code is
+        compiler generated. The Erlang Compiler does not emit warnings
+        for such code.</p>
+      </item>
+      <tag><c>record</c></tag>
+      <item><p>A Boolean indicating if the origin of the abstract
+        code is a record. Used by Dialyzer to assign types to tuple
+        elements.</p>
+      </item>
+    </taglist>
+    <p>The functions
+      <seealso marker="erl_scan#column/1">column()</seealso>,
+      <seealso marker="erl_scan#end_location/1">end_location()</seealso>,
+      <seealso marker="erl_scan#line/1">line()</seealso>,
+      <seealso marker="erl_scan#location/1">location()</seealso>, and
+      <seealso marker="erl_scan#text/1">text()</seealso>
+      in the <c>erl_scan</c> module can be used for inspecting
+      annotations in tokens.</p>
+    <p>The functions
+      <seealso marker="erl_parse#map_anno/2">map_anno()</seealso>,
+      <seealso marker="erl_parse#fold_anno/3">fold_anno()</seealso>,
+      <seealso marker="erl_parse#mapfold_anno/3">mapfold_anno()</seealso>,
+      <seealso marker="erl_parse#new_anno/1">new_anno()</seealso>,
+      <seealso marker="erl_parse#anno_from_term/1">
+      anno_from_term()</seealso>, and
+      <seealso marker="erl_parse#anno_to_term/1">
+      anno_to_term()</seealso> in the <c>erl_parse</c> module can be
+      used for manipulating annotations in abstract code.
+    </p>
+  </description>
+
+  <datatypes>
+    <datatype>
+      <name><marker id="type-anno">anno()</marker></name>
+      <desc><p>A collection of annotations.</p>
+      </desc>
+    </datatype>
+    <datatype>
+      <name name="anno_term"></name>
+      <desc>
+        <p>The term representing a collection of annotations. It is
+          either a <c>location()</c> or a list of key-value pairs.</p>
+      </desc>
+    </datatype>
+    <datatype>
+      <name name="column"></name>
+    </datatype>
+    <datatype>
+      <name name="line"></name>
+      <desc>
+      <p>To be changed to a non-negative integer in Erlang/OTP 19.0.</p>
+      </desc>
+    </datatype>
+    <datatype>
+      <name name="location"></name>
+    </datatype>
+    <datatype>
+      <name name="text"></name>
+    </datatype>
+  </datatypes>
+
+  <funcs>
+    <func>
+      <name name="column" arity="1"/>
+      <type name="column"></type>
+      <fsummary>Return the column</fsummary>
+      <desc>
+        <p>Returns the column of the annotations <anno>Anno</anno>.
+        </p>
+      </desc>
+    </func>
+    <func>
+      <name name="end_location" arity="1"/>
+      <type name="location"></type>
+      <fsummary>Return the end location of the text</fsummary>
+      <desc>
+        <p>Returns the end location of the text of the
+          annotations <anno>Anno</anno>. If there is no text,
+          <c>undefined</c> is returned.
+        </p>
+      </desc>
+    </func>
+    <func>
+      <name name="file" arity="1"/>
+      <type name="filename"></type>
+      <fsummary>Return the filename</fsummary>
+      <desc>
+        <p>Returns the filename of the annotations <anno>Anno</anno>.
+          If there is no filename, <c>undefined</c> is returned.
+        </p>
+      </desc>
+    </func>
+    <func>
+      <name name="from_term" arity="1"/>
+      <fsummary>Return annotations given a term</fsummary>
+      <desc>
+        <p>Returns annotations with the representation <anno>Term</anno>.
+        </p>
+        <!--
+        <p>Although it is possible to create new annotations by calling
+          <c>from_term/1</c>, the intention is that one should not do
+          so - the proper way to create annotations is to call
+          <c>new/1</c> and then modify the annotations
+          by calling the <c>set_*</c> functions.</p>
+        -->
+        <p>See also <seealso marker="#to_term/1">to_term()</seealso>.
+        </p>
+      </desc>
+    </func>
+    <func>
+      <name name="generated" arity="1"/>
+      <type name="generated"></type>
+      <fsummary>Return the generated Boolean</fsummary>
+      <desc>
+        <p>Returns <c>true</c> if the annotations <anno>Anno</anno>
+          has been marked as generated. The default is to return
+          <c>false</c>.
+        </p>
+      </desc>
+    </func>
+    <func>
+      <name name="is_anno" arity="1"/>
+      <fsummary>Test for a collection of annotations</fsummary>
+      <desc>
+        <p>Returns <c>true</c> if <anno>Term</anno> is a collection of
+          annotations, <c>false</c> otherwise.</p>
+      </desc>
+    </func>
+    <func>
+      <name name="line" arity="1"/>
+      <type name="line"></type>
+      <fsummary>Return the line</fsummary>
+      <desc>
+        <p>Returns the line of the annotations <anno>Anno</anno>.
+        </p>
+      </desc>
+    </func>
+    <func>
+      <name name="location" arity="1"/>
+      <type name="location"></type>
+      <fsummary>Return the location</fsummary>
+      <desc>
+        <p>Returns the location of the annotations <anno>Anno</anno>.
+        </p>
+      </desc>
+    </func>
+    <func>
+      <name name="new" arity="1"/>
+      <type name="location"></type>
+      <fsummary>Create a new collection of annotations</fsummary>
+      <desc>
+        <p>Creates a new collection of annotations given a location.</p>
+      </desc>
+    </func>
+    <func>
+      <name name="set_file" arity="2"/>
+      <type name="filename"></type>
+      <fsummary>Modify the filename</fsummary>
+      <desc>
+        <p>Modifies the filename of the annotations <anno>Anno</anno>.
+        </p>
+      </desc>
+    </func>
+    <func>
+      <name name="set_generated" arity="2"/>
+      <type name="generated"></type>
+      <fsummary>Modify the generated marker</fsummary>
+      <desc>
+        <p>Modifies the generated marker of the annotations
+          <anno>Anno</anno>.
+        </p>
+      </desc>
+    </func>
+    <func>
+      <name name="set_line" arity="2"/>
+      <type name="line"></type>
+      <fsummary>Modify the line</fsummary>
+      <desc>
+        <p>Modifies the line of the annotations <anno>Anno</anno>.
+        </p>
+      </desc>
+    </func>
+    <func>
+      <name name="set_location" arity="2"/>
+      <type name="location"></type>
+      <fsummary>Modify the location</fsummary>
+      <desc>
+        <p>Modifies the location of the annotations <anno>Anno</anno>.
+        </p>
+      </desc>
+    </func>
+    <func>
+      <name name="set_record" arity="2"/>
+      <type name="record"></type>
+      <fsummary>Modify the record marker</fsummary>
+      <desc>
+        <p>Modifies the record marker of the annotations <anno>Anno</anno>.
+        </p>
+      </desc>
+    </func>
+    <func>
+      <name name="set_text" arity="2"/>
+      <type name="text"></type>
+      <fsummary>Modify the text</fsummary>
+      <desc>
+        <p>Modifies the text of the annotations <anno>Anno</anno>.
+        </p>
+      </desc>
+    </func>
+    <func>
+      <name name="text" arity="1"/>
+      <type name="text"></type>
+      <fsummary>Return the text</fsummary>
+      <desc>
+        <p>Returns the text of the annotations <anno>Anno</anno>.
+        If there is no text, <c>undefined</c> is returned.
+        </p>
+      </desc>
+    </func>
+    <func>
+      <name name="to_term" arity="1"/>
+      <fsummary>Return the term representing a collection of
+        annotations</fsummary>
+      <desc>
+        <p>Returns the term representing the annotations <anno>Anno</anno>.
+        </p>
+        <p>See also <seealso marker="#from_term/1">from_term()</seealso>.
+        </p>
+      </desc>
+    </func>
+  </funcs>
+  <section>
+    <title>See Also</title>
+    <p><seealso marker="erl_scan">erl_scan(3)</seealso>,
+       <seealso marker="erl_parse">erl_parse(3)</seealso>
+    </p>
+  </section>
+</erlref>