Merge pull request #7942 from fnchooft/add-xmerl-indent-module

Add formatting module for xml output

The xmerl_xml_indent module was added to provide indented output instead of the standard xmerl_xml output.

OTP-18922

lib/xmerl/doc/src/xmerl_ug.xmlsrc

@@ -11,15 +11,15 @@
       Licensed under the Apache License, Version 2.0 (the "License");
       you may not use this file except in compliance with the License.
       You may obtain a copy of the License at
- 
+
           http://www.apache.org/licenses/LICENSE-2.0
 
       Unless required by applicable law or agreed to in writing, software
       distributed under the License is distributed on an "AS IS" BASIS,
       WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
       See the License for the specific language governing permissions and
       limitations under the License.
-    
+
     </legalnotice>
 
     <title>xmerl</title>
@@ -171,7 +171,7 @@ Grand Danois\
     <p>If you want to parse the XML file motorcycles.xml you run
       it in the Erlang shell like:</p>
     <pre>
-3> {ParsResult,Misc}=xmerl_scan:file("motorcycles.xml"). 
+3> {ParseResult,Misc}=xmerl_scan:file("motorcycles.xml").
 {{xmlElement,motorcycles,
              motorcycles,
              [],
@@ -279,7 +279,7 @@ Grand Danois\
       <item>Name = atom()</item>
       <item>Value = IOString | atom() | integer()</item>
     </list>
-    <p>See also reference manual for 
+    <p>See also reference manual for
       <seeerl marker="xmerl#export_simple-3">xmerl</seeerl></p>
     <p>If you want to add the information about a black Harley
       Davidsson 1200 cc Sportster motorcycle from 2003 that is in
@@ -359,6 +359,18 @@ Data =
     ...    </pre>
     <p>The result will be: </p>
     <codeinclude file="new_motorcycles2.txt" tag="" type="none"></codeinclude>
+    <p>
+
+    The generated XML above was formatted for readability.
+
+    Another exporter which indents the code with 2 spaces can also be used.
+
+    In order to use it one only needs to change the export-module:</p>
+    <pre>
+      ...
+        Export=xmerl:export_simple([NewRootEl],xmerl_xml_indent,[{prolog,Prolog}]),
+      ...
+    </pre>
   </section>
 
   <section>
@@ -488,4 +500,3 @@ template(E = #xmlElement{name='bike'}) ->
       elements and the 'manufacturer' elements are not in order.</p>
   </section>
 </chapter>
-

lib/xmerl/src/Makefile

@@ -77,6 +77,7 @@ MODULES = $(EDOC_MODULES) \
 	xmerl_validate \
 	xmerl_xlate \
 	xmerl_xml \
+	xmerl_xml_indent \
 	xmerl_xpath_lib \
 	xmerl_xpath_parse \
 	xmerl_xpath_pred \

lib/xmerl/src/xmerl.app.src

@@ -27,6 +27,7 @@
 	xmerl_validate,
 	xmerl_xlate,
 	xmerl_xml,
+	xmerl_xml_indent,
 	xmerl_xpath,
 	xmerl_xpath_lib,
 	xmerl_xpath_parse,

lib/xmerl/src/xmerl_xml_indent.erl

@@ -0,0 +1,86 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2003-2016. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% %CopyrightEnd%
+%%
+
+%% Description  : Callback module for exporting complete or simple forms to indented XML.
+%%
+%% This module indents the xml with 2 spaces and a newline \n.
+%% Currently the implementation does not allow it to be configured.
+%% The implementation is based on the same Elixir implementation.
+%% https://hexdocs.pm/xmerl_xml_indent/readme.html
+
+-module(xmerl_xml_indent).
+
+-export(['#xml-inheritance#'/0]).
+
+-export(['#root#'/4,
+	 '#element#'/5,
+	 '#text#'/1]).
+
+-import(xmerl_lib, [markup/3, empty_tag/2, export_text/1]).
+
+-include("xmerl.hrl").
+-include("xmerl_internal.hrl").
+
+
+'#xml-inheritance#'() -> [].
+
+
+%% The '#text#' function is called for every text segment.
+
+'#text#'(Text) ->
+    export_text(Text).
+
+
+%% The '#root#' tag is called when the entire structure has been
+%% exported. It does not appear in the structure itself.
+
+'#root#'(Data, [#xmlAttribute{name=prolog,value=V}], [], _E) ->
+    [V,Data];
+'#root#'(Data, _Attrs, [], _E) ->
+    ["<?xml version=\"1.0\"?>\n", Data].
+
+
+%% The '#element#' function is the default handler for XML elements.
+
+'#element#'(Tag, [], Attrs, _Parents, _E) ->
+    empty_tag(Tag, Attrs);
+'#element#'(Tag, Data, Attrs, Parents, _E) ->
+    IsCharData = is_char(Data),
+    NewData =
+        case IsCharData of
+            true ->
+                LengthParents = length(Parents),
+                %% Push all the data over Lvl spaces.
+                [
+                    indent(LengthParents + 1) ++ DataEntry
+                 || DataEntry <- Data
+                ] ++ indent(LengthParents);
+            false ->
+                Data
+        end,
+    markup(Tag, Attrs, NewData).
+
+is_char([[X|_]|_]) ->
+    not is_integer(X);
+is_char(Data) when is_list(Data) ->
+    false.
+
+indent(Level) ->
+    [$\n | lists:duplicate(2 * Level, $\s)].