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<H1><a name="Doxygen">17 SWIG and Doxygen Translation</a></H1>
<!-- INDEX -->
<div class="sectiontoc">
<ul>
<li><a href="#Doxygen_translation_overview">Doxygen translation overview</a>
<li><a href="#Doxygen_file_preparation">Preparations</a>
<ul>
<li><a href="#Doxygen_running_swig">Enabling Doxygen translation</a>
<li><a href="#Doxygen_features">Doxygen-specific %feature directives</a>
<ul>
<li><a href="#Doxygen_notranslate">doxygen:notranslate</a>
<li><a href="#Doxygen_alias">doxygen:alias:&lt;command-name&gt;</a>
<li><a href="#Doxygen_ignore">doxygen:ignore:&lt;command-name&gt;</a>
<li><a href="#Doxygen_nolinktranslate">doxygen:nolinktranslate</a>
<li><a href="#Doxygen_nostripparams">doxygen:nostripparams</a>
</ul>
<li><a href="#Doxygen_additional_options">Additional command line options</a>
</ul>
<li><a href="#Doxygen_to_javadoc">Doxygen to Javadoc</a>
<ul>
<li><a href="#Doxygen_basic_example">Basic example</a>
<li><a href="#Doxygen_javadoc_tags">Javadoc tags</a>
<li><a href="#Doxygen_unsupported_tags">Unsupported tags</a>
<li><a href="#Doxygen_further_details">Further details</a>
</ul>
<li><a href="#Doxygen_to_pydoc">Doxygen to Pydoc</a>
<ul>
<li><a href="#Doxygen_python_basic_example">Basic example</a>
<li><a href="#Doxygen_pydoc_tags">Pydoc translator</a>
<li><a href="#Doxygen_python_unsupported_tags">Unsupported tags</a>
<li><a href="#Doxygen_python_further_details">Further details</a>
</ul>
<li><a href="#Doxygen_troubleshooting">Troubleshooting</a>
<ul>
<li><a href="#troubleshooting_ifndef">Problem with conditional compilation</a>
</ul>
<li><a href="#Doxygen_developer_details">Developer information</a>
<ul>
<li><a href="#Doxygen_translator_design">Doxygen translator design</a>
<li><a href="#Doxygen_debugging_commands">Debugging the Doxygen parser and translator</a>
<li><a href="#Doxygen_tests">Tests</a>
</ul>
<li><a href="#Doxygen_language_extension">Extending to other languages</a>
</ul>
</div>
<!-- INDEX -->
<p>
This chapter describes SWIG's support for translating Doxygen comments
found in interface and header files into a target language's normal
documentation language. Currently only Javadoc and Pydoc is
supported.
</p>
<H2><a name="Doxygen_translation_overview">17.1 Doxygen translation overview</a></H2>
<p>
The Doxygen Translation module of SWIG adds an extra layer of
functionality to SWIG, allowing automated translation of <a href=
"http://www.doxygen.nl/manual/">Doxygen</a> formatted comments
from input files into a documentation language more suited for the
target language. Currently this module only translates into Javadoc
and Pydoc for the SWIG Java and Python modules.
Other extensions could be added at a later date.
The Doxygen Translation module originally started as
a <a href="https://developers.google.com/open-source/gsoc/2008/">Google Summer of
Code</a> proposal from Summer 2008.
</p>
<H2><a name="Doxygen_file_preparation">17.2 Preparations</a></H2>
<p>
To make use of the comment translation system, your documentation
comments must be in properly formatted <a href=
"http://www.doxygen.nl/manual/">Doxygen.</a> Doxygen comments can be
present in your main SWIG interface file or any header file that it
imports. You are advised to be validate that your comments compile
properly with Doxygen before you try to translate them. Doxygen
itself is a more comprehensive tool and can provide you better feedback for
correcting any syntax errors that may be present. Please look at
Doxygen's <a href=
"http://www.doxygen.nl/manual/docblocks.html"> Documenting the
code</a> for the full comment format specifications. However, SWIG's
Doxygen parser will still report many errors and warnings found
in comments (like unterminated strings or missing ending tags).
</p>
<p>
Currently, the whole subset of Doxygen comment styles is supported
(See <a href="http://www.doxygen.nl/manual/docblocks.html">
Documenting the code</a>). Here they are:
</p>
<div class="code"><pre>
/**
* Javadoc style comment, multiline
*/
/*!
* QT-style comment, multiline
*/
/**
Any of the above, but without intermediate *'s
*/
/// Single-line comment
//! Another single-line comment
</pre></div>
<p>
Also any of the above with '<tt>&lt;</tt>' added after comment-starting symbol,
like <tt>/**&lt;, /*!&lt;, ///&lt;, </tt> or <tt> //!&lt;</tt> will be
treated as a post-comment and will be assigned to the code before the
comment.
Any number of '<tt>*</tt>' or '<tt>/</tt>' within a Doxygen comment is
considered to be a separator and is not included in the final comment,
so you may safely use comments like <tt>/*********/</tt>
or <tt>//////////</tt>.
</p>
<p>
Please note, as SWIG parses the input file by itself with strict grammar,
there is only a limited support for various cases of comment placement
in the file.
</p>
<p>
Comments can be placed before C/C++ expressions on separate lines:
</p>
<div class="code"><pre>
/**
* Some comment
*/
void someOtherFunction();
/**
* Some comment
*/
void someFunction();
class Shape {
/*
* Calculate the area in cm^2
*/
int getArea();
}
</pre></div>
<p>
After C/C++ expressions at the end of the line:
</p>
<div class="code"><pre>
int someVariable = 9; ///&lt; This is a var holding magic number 9
void doNothing(); ///&lt; This does nothing, nop
</pre></div>
<p>
and in some special cases, like function parameter comments:
</p>
<div class="code"><pre>
void someFunction(
int a ///&lt; Some parameter
);
</pre></div>
<p>
or enum element comments:
</p>
<div class="code"><pre>
enum E_NUMBERS
{
EN_ZERO, ///&lt; The first enum item, gets zero as it's value
EN_ONE, ///&lt; The second, EN_ONE=1
EN_THREE
};
</pre></div>
<p>
Currently only comments directly before or after the code items
are supported. Doxygen also supports comments containing structural commands,
where the comments for a code item are not put directly before or after the code item.
These structural commands are stripped out by SWIG and are not assigned to anything.
</p>
<H3><a name="Doxygen_running_swig">17.2.1 Enabling Doxygen translation</a></H3>
<p>
Doxygen comments translation is disabled by default and needs to be explicitly
enabled using the command line <tt>-doxygen</tt> option for the languages that
do support it (currently Java and Python).
</p>
<H3><a name="Doxygen_features">17.2.2 Doxygen-specific %feature directives</a></H3>
<p>
Translation of Doxygen comments is influenced by the following <a
href="Customization.html#Customization_features">%feature directives</a>:
</p>
<H4><a name="Doxygen_notranslate">17.2.2.1 doxygen:notranslate</a></H4>
<p>
Turns off translation of Doxygen comments to the target language syntax: the
original comment will be copied to the output unchanged. This is useful if you
want to use Doxygen itself to generate documentation for the target language
instead of the corresponding language tool (<tt>javadoc</tt>, <tt>sphinx</tt>,
...).
</p>
<H4><a name="Doxygen_alias">17.2.2.2 doxygen:alias:&lt;command-name&gt;</a></H4>
<p>
Specify an alias for a Doxygen command with the given name. This can be useful
for custom Doxygen commands which can be defined using <tt>ALIASES</tt> option
for Doxygen itself but which are unknown to SWIG. <tt>"command-name"</tt> is the
name of the command in the Doxyfile, e.g. if it contains
</p>
<div class="code"><pre>
ALIASES = "sideeffect=\par Side Effects:\n"
</pre></div>
<p>
Then you could also specify the same expansion for SWIG with:
</p>
<div class="code"><pre>
%feature("doxygen:alias:sideeffect") "\par Side Effects:\n"
</pre></div>
<p>
Please note that command arguments are not currently supported with this
feature.
</p>
<p>
Notice that it is perfectly possible and potentially useful to define the alias
expansion differently depending on the target language, e.g. with
</p>
<div class="code"><pre>
#ifdef SWIGJAVA
%feature("doxygen:alias:not_for_java") "This functionality is not available for Java"
#else
%feature("doxygen:alias:not_for_java") ""
#endif
</pre></div>
<p>
you could use <tt>@not_for_java</tt> in the documentation comments of all
functions which can't, for whatever reason, be currently exposed in Java
wrappers of the C++ API.
</p>
<H4><a name="Doxygen_ignore">17.2.2.3 doxygen:ignore:&lt;command-name&gt;</a></H4>
<p>
This feature makes it possible to just ignore an unknown Doxygen command, instead of
replacing it with the predefined text that <tt>doxygen:alias</tt> does.
For example, you could use
</p>
<div class="code"><pre>
%feature("doxygen:ignore:transferfull") Fantastic();
/**
A fantastic function.
@transferfull Command ignored, but anything here is still included.
*/
int * Fantastic();
</pre></div>
<p>
if you use a custom Doxygen <tt>transferfull</tt> command to indicate that the
return value ownership is transferred to the caller, as this information doesn't
make much sense for the other languages without explicit ownership management.
</p>
<p>
Doxygen syntax is rather rich and, in addition to simple commands such as
<tt>@transferfull</tt>, it is also possible to define commands with arguments.
As explained in <a href="http://www.doxygen.nl/manual/commands.html">Doxygen documentation</a>,
the arguments can have a range of a single word, everything until the end of
line or everything until the end of the next paragraph. Currently, only the "end
of line" case is supported using the <tt>range="line"</tt> argument of the
feature directive:
</p>
<div class="code"><pre>
// Ignore occurrences of
//
// @compileroptions Some special C++ compiler options.
//
// in Doxygen comments as C++ options are not interesting for the target language
// developers.
%feature("doxygen:ignore:compileroptions", range="line") Amazing();
/**
An amazing function.
@compileroptions This function must be compiled with /EHa when using MSVC.
*/
void Amazing();
</pre></div>
<p>
In addition, it is also possible to have custom pairs of begin/end tags,
similarly to the standard Doxygen <tt>@code/@endcode</tt>, for example. Such
tags can also be ignored using the special value of <tt>range</tt> starting with
<tt>end</tt> to indicate that the range is an interval, for example:
</p>
<div class="code"><pre>
%feature("doxygen:ignore:forcpponly", range="end"); // same as "end:endforcpponly"
/**
An incredible function.
@forcpponly
This is C++-specific.
@endforcpponly
*/
void Incredible();
</pre></div>
<p>
would ignore everything between <tt>@forcpponly</tt> and <tt>@endforcpponly</tt>
commands in Doxygen comments. By default, the name of the end command is the
same as of the start one with "end" prefix, following Doxygen conventions, but
this can be overridden by providing the end command name after the colon.
</p>
<p>
This example shows how custom tags can be used to bracket anything specific to
C++ and prevent it from appearing in the target language documentation.
Conversely, another pair of custom tags could be used to put target language
specific information in the C++ comments. In this case, only the custom tags
themselves should be ignored, but their contents should be parsed as usual and
<tt>contents="parse"</tt> can be used for this:
</p>
<div class="code"><pre>
%feature("doxygen:ignore:beginPythonOnly", range="end:endPythonOnly", contents="parse");
/**
A splendid function.
@beginPythonOnly
This is specific to @b Python.
@endPythonOnly
*/
void Splendid();
</pre></div>
<p>
Putting everything together, if these directives are in effect:
</p>
<div class="code"><pre>
%feature("doxygen:ignore:transferfull");
%feature("doxygen:ignore:compileroptions", range="line");
%feature("doxygen:ignore:forcpponly", range="end");
%feature("doxygen:ignore:beginPythonOnly", range="end:endPythonOnly", contents="parse");
</pre></div>
<p>
then the following C++ Doxygen comment:
</p>
<div class="code"><pre>
/**
A contrived example of ignoring too many commands in one comment.
@forcpponly
This is C++-specific.
@endforcpponly
@beginPythonOnly
This is specific to @b Python.
@endPythonOnly
@transferfull Command ignored, but anything here is still included.
@compileroptions This function must be compiled with /EHa when using MSVC.
*/
int * Contrived();
</pre></div>
<p>
would be translated to this comment in Python:
</p>
<div class="code"><pre>
def func():
r"""
A contrived example of ignoring too many commands in one comment.
This is specific to **Python**.
Command ignored, but anything here is still included.
"""
...
</pre></div>
<H4><a name="Doxygen_nolinktranslate">17.2.2.4 doxygen:nolinktranslate</a></H4>
<p>
Turn off automatic link-objects translation.
This is only applicable to Java at the moment.
</p>
<H4><a name="Doxygen_nostripparams">17.2.2.5 doxygen:nostripparams</a></H4>
<p>
Turn off stripping of <tt>@param</tt> and <tt>@tparam</tt>
Doxygen commands if the parameter is not found in the function signature.
This is only applicable to Java at the moment.
</p>
<H3><a name="Doxygen_additional_options">17.2.3 Additional command line options</a></H3>
<p>
ALSO TO BE ADDED (Javadoc auto brief?)
</p>
<H2><a name="Doxygen_to_javadoc">17.3 Doxygen to Javadoc</a></H2>
<p>
If translation is enabled, Javadoc formatted comments should be
automatically placed in the correct locations in the resulting module
and proxy files.
</p>
<H3><a name="Doxygen_basic_example">17.3.1 Basic example</a></H3>
<p>
Here is an example segment from an included header file
</p>
<div class="code"><pre>
/*! This is describing class Shape
\author Bob
*/
class Shape {
public:
Shape() {
nshapes++;
}
virtual ~Shape() {
nshapes--;
};
double x, y; /*!&lt; Important Variables */
void move(double dx, double dy); /*!&lt; Moves the Shape */
virtual double area(void) = 0; /*!&lt; \return the area */
virtual double perimeter(void) = 0; /*!&lt; \return the perimeter */
static int nshapes;
};
</pre></div>
<p>
Simply running SWIG should result in the following code being present in Shapes.java
</p>
<div class="targetlang"><pre>
/**
* This is describing class Shape
* @author Bob
*
*/
public class Shape {
...
/**
* Important Variables
*/
public void setX(double value) {
ShapesJNI.Shape_x_set(swigCPtr, this, value);
}
/**
* Important Variables
*/
public double getX() {
return ShapesJNI.Shape_x_get(swigCPtr, this);
}
/**
* Moves the Shape
*/
public void move(double dx, double dy) {
ShapesJNI.Shape_move(swigCPtr, this, dx, dy);
}
/**
* @return the area
*/
public double area() {
return ShapesJNI.Shape_area(swigCPtr, this);
}
/**
* @return the perimeter
*/
public double perimeter() {
return ShapesJNI.Shape_perimeter(swigCPtr, this);
}
}
</pre></div>
<p>
The code Java-wise should be identical to what would have been
generated without the doxygen functionality enabled. When the Doxygen Translator
module encounters a comment that contains nothing useful or a doxygen comment that it cannot
parse, it will not affect the functionality of the SWIG generated
code.
</p>
<p>
The Javadoc translator will handle most of the tags conversions (see the
table below). It will also automatically translate link-objects
params, in \see and \link...\endlink commands. For example,
'someFunction(std::string)' will be converted to
'someFunction(String)'. If
you don't want such behaviour, you could turn this off by using the
'doxygen:nolinktranslate' feature. Also all '\param' and '\tparam'
commands are stripped out, if the specified parameter is not present in
the function. Use 'doxygen:nostripparams' to avoid.
</p>
<p>
Javadoc translator features summary
(see <a href="Customization.html#Customization_features">%feature
directives</a>):
</p>
<H3><a name="Doxygen_javadoc_tags">17.3.2 Javadoc tags</a></H3>
<p>
Here is the list of all Doxygen tags and the description of how they are translated to Javadoc
</p>
<div class="diagram">
<table border="0" summary="Java Doxygen tags">
<tr>
<th align="left">Doxygen tags</th>
</tr>
<tr>
<td>\a</td>
<td>wrapped with &lt;i&gt; html tag</td>
</tr>
<tr>
<td>\arg</td>
<td>wrapped with &lt;li&gt; html tag</td>
</tr>
<tr>
<td>\author</td>
<td>translated to @author</td>
</tr>
<tr>
<td>\authors</td>
<td>translated to @author</td>
</tr>
<tr>
<td>\b</td>
<td>wrapped with &lt;b&gt; html tag</td>
</tr>
<tr>
<td>\c</td>
<td>wrapped with &lt;code&gt; html tag</td>
</tr>
<tr>
<td>\cite</td>
<td>wrapped with &lt;i&gt; html tag</td>
</tr>
<tr>
<td>\code</td>
<td>translated to {@code ...}</td>
</tr>
<tr>
<td>\code{&lt;ext&gt;}</td>
<td>translated to {@code ...}; code language extension is ignored</td>
</tr>
<tr>
<td>\cond</td>
<td>translated to 'Conditional comment: &lt;condition&gt;'</td>
</tr>
<tr>
<td>\copyright</td>
<td>replaced with 'Copyright:'</td>
</tr>
<tr>
<td>\deprecated</td>
<td>translated to @deprecated</td>
</tr>
<tr>
<td>\e</td>
<td>wrapped with &lt;i&gt; html tag</td>
</tr>
<tr>
<td>\else</td>
<td>replaced with '}Else:{'</td>
</tr>
<tr>
<td>\elseif</td>
<td>replaced with '}Else if: &lt;condition&gt;{'</td>
</tr>
<tr>
<td>\em</td>
<td>wrapped with &lt;i&gt; html tag</td>
</tr>
<tr>
<td>\endcode</td>
<td>see note for \code</td>
</tr>
<tr>
<td>\endcond</td>
<td>replaced with 'End of conditional comment.'</td>
</tr>
<tr>
<td>\endif</td>
<td>replaced with '}'</td>
</tr>
<tr>
<td>\endlink</td>
<td>see note for \link</td>
</tr>
<tr>
<td>\endverbatim</td>
<td>see note for \verbatim</td>
</tr>
<tr>
<td>\exception</td>
<td>translated to @exception</td>
</tr>
<tr>
<td>\f$, \f[, \f], \f{, \f}</td>
<td>LateX formulas are left unchanged</td>
</tr>
<tr>
<td>\if</td>
<td>replaced with 'If: &lt;condition&gt; {'</td>
</tr>
<tr>
<td>\ifnot</td>
<td>replaced with 'If not: &lt;condition&gt; {'</td>
</tr>
<tr>
<td>\image</td>
<td>translated to &lt;img/&gt; html tag only if target=HTML</td>
</tr>
<tr>
<td>\li</td>
<td>wrapped with &lt;li&gt; html tag</td>
</tr>
<tr>
<td>\link</td>
<td>translated to {@link ...}</td>
</tr>
<tr>
<td>\n</td>
<td>replaced with newline char</td>
</tr>
<tr>
<td>\note</td>
<td>replaced with 'Note:'</td>
</tr>
<tr>
<td>\overload</td>
<td>prints 'This is an overloaded ...' according to Doxygen docs</td>
</tr>
<tr>
<td>\p</td>
<td>wrapped with &lt;code&gt; html tag</td>
</tr>
<tr>
<td>\par</td>
<td>replaced with &lt;p alt='title'&gt;...&lt;/p&gt;</td>
</tr>
<tr>
<td>\param</td>
<td>translated to @param</td>
</tr>
<tr>
<td>\param[&lt;dir&gt;]</td>
<td>translated to @param; parameter direction ('in'; 'out'; or 'in,out') is ignored</td>
</tr>
<tr>
<td>\remark</td>
<td>replaced with 'Remarks:'</td>
</tr>
<tr>
<td>\remarks</td>
<td>replaced with 'Remarks:'</td>
</tr>
<tr>
<td>\result</td>
<td>translated to @return</td>
</tr>
<tr>
<td>\return</td>
<td>translated to @return</td>
</tr>
<tr>
<td>\returns</td>
<td>translated to @return</td>
</tr>
<tr>
<td>\sa</td>
<td>translated to @see</td>
</tr>
<tr>
<td>\see</td>
<td>translated to @see</td>
</tr>
<tr>
<td>\since</td>
<td>translated to @since</td>
</tr>
<tr>
<td>\throw</td>
<td>translated to @throws</td>
</tr>
<tr>
<td>\throws</td>
<td>translated to @throws</td>
</tr>
<tr>
<td>\todo</td>
<td>replaced with 'TODO:'</td>
</tr>
<tr>
<td>\tparam</td>
<td>translated to @param</td>
</tr>
<tr>
<td>\verbatim</td>
<td>translated to {@literal ...}</td>
</tr>
<tr>
<td>\version</td>
<td>translated to @version</td>
</tr>
<tr>
<td>\warning</td>
<td>translated to 'Warning:'</td>
</tr>
<tr>
<td>\$</td>
<td>prints $ char</td>
</tr>
<tr>
<td>\@</td>
<td>prints @ char</td>
</tr>
<tr>
<td>\\</td>
<td>prints \ char</td>
</tr>
<tr>
<td>\&amp;</td>
<td>prints &amp; char</td>
</tr>
<tr>
<td>\~</td>
<td>prints ~ char</td>
</tr>
<tr>
<td>\&lt;</td>
<td>prints &lt; char</td>
</tr>
<tr>
<td>\&gt;</td>
<td>prints &gt; char</td>
</tr>
<tr>
<td>\#</td>
<td>prints # char</td>
</tr>
<tr>
<td>\%</td>
<td>prints % char</td>
</tr>
<tr>
<td>\&quot;</td>
<td>prints &quot; char</td>
</tr>
<tr>
<td>\.</td>
<td>prints . char</td>
</tr>
<tr>
<td>\::</td>
<td>prints ::</td>
</tr>
</table>
</div>
<H3><a name="Doxygen_unsupported_tags">17.3.3 Unsupported tags</a></H3>
<p>
Doxygen has a wealth of tags such as @latexonly that have no
equivalent in Javadoc (all supported tags are listed in
<a href="https://docs.oracle.com/javase/7/docs/technotes/tools/windows/javadoc.html">Javadoc documentation</a>).
As a result several tags have no
translation or particular use, such as some linking and section tags.
These are suppressed with their content just printed out (if the tag has any
sense, typically text content).
Here is the list of these tags:
</p>
<div class="diagram">
<b>Unsupported Doxygen tags</b>
<ul style="list-style-type:none;column-count:4;">
<li>\addindex</li>
<li>\addtogroup</li>
<li>\anchor</li>
<li>\attention</li>
<li>\brief</li>
<li>\bug</li>
<li>\callergraph</li>
<li>\callgraph</li>
<li>\category</li>
<li>\class</li>
<li>\copybrief</li>
<li>\copydetails</li>
<li>\copydoc</li>
<li>\date</li>
<li>\def</li>
<li>\defgroup</li>
<li>\details</li>
<li>\dir</li>
<li>\dontinclude</li>
<li>\dot</li>
<li>\dotfile</li>
<li>\enddot</li>
<li>\endhtmlonly</li>
<li>\endinternal</li>
<li>\endlatexonly</li>
<li>\endmanonly</li>
<li>\endmsc</li>
<li>\endrtfonly</li>
<li>\endxmlonly</li>
<li>\enum</li>
<li>\example</li>
<li>\extends</li>
<li>\file</li>
<li>\fn</li>
<li>\headerfile</li>
<li>\hideinitializer</li>
<li>\htmlinclude</li>
<li>\htmlonly</li>
<li>\implements</li>
<li>\include</li>
<li>\includelineno</li>
<li>\ingroup</li>
<li>\interface</li>
<li>\internal</li>
<li>\invariant</li>
<li>\latexonly</li>
<li>\line</li>
<li>\mainpage</li>
<li>\manonly</li>
<li>\memberof</li>
<li>\msc</li>
<li>\mscfile</li>
<li>\name</li>
<li>\namespace</li>
<li>\nosubgrouping</li>
<li>\package</li>
<li>\page</li>
<li>\paragraph</li>
<li>\post</li>
<li>\pre</li>
<li>\private</li>
<li>\privatesection</li>
<li>\property</li>
<li>\protected</li>
<li>\protectedsection</li>
<li>\protocol</li>
<li>\public</li>
<li>\publicsection</li>
<li>\ref</li>
<li>\related</li>
<li>\relatedalso</li>
<li>\relates</li>
<li>\relatesalso</li>
<li>\retval</li>
<li>\rtfonly</li>
<li>\section</li>
<li>\short</li>
<li>\showinitializer</li>
<li>\skip</li>
<li>\skipline</li>
<li>\snippet</li>
<li>\struct</li>
<li>\subpage</li>
<li>\subsection</li>
<li>\subsubsection</li>
<li>\tableofcontents</li>
<li>\test</li>
<li>\typedef</li>
<li>\union</li>
<li>\until</li>
<li>\var</li>
<li>\verbinclude</li>
<li>\weakgroup</li>
<li>\xmlonly</li>
<li>\xrefitem</li>
</ul>
</div>
<p>
If one of the following Doxygen tags appears as the first tag in a
comment, the whole comment block is ignored:
<!-- see parser.y, function isStructuralDoxygen() -->
</p>
<div class="diagram">
<b>Ignored Doxygen tags</b>
<ul style="list-style-type:none;column-count:4;">
<li>\addtogroup</li>
<li>\callergraph</li>
<li>\callgraph</li>
<li>\category</li>
<li>\class</li>
<li>\def</li>
<li>\defgroup</li>
<li>\dir</li>
<li>\enum</li>
<li>\example</li>
<li>\file</li>
<li>\fn</li>
<li>\headerfile</li>
<li>\hideinitializer</li>
<li>\interface</li>
<li>\internal</li>
<li>\mainpage</li>
<li>\name</li>
<li>\namespace</li>
<li>\nosubgrouping</li>
<li>\overload</li>
<li>\package</li>
<li>\page</li>
<li>\property</li>
<li>\protocol</li>
<li>\relates</li>
<li>\relatesalso</li>
<li>\showinitializer</li>
<li>\struct</li>
<li>\typedef</li>
<li>\union</li>
<li>\var</li>
<li>\weakgroup</li>
</ul>
</div>
<H3><a name="Doxygen_further_details">17.3.4 Further details</a></H3>
<p>
TO BE ADDED.
</p>
<H2><a name="Doxygen_to_pydoc">17.4 Doxygen to Pydoc</a></H2>
<p>
If translation is enabled, Pydoc formatted comments should be
automatically placed in the correct locations in the resulting module
and proxy files. The problem is that Pydoc has no tag mechanism like
Doxygen or Javadoc, so most of Doxygen commands are translated by merely
copying the appropriate command text.
</p>
<H3><a name="Doxygen_python_basic_example">17.4.1 Basic example</a></H3>
<p>
Here is an example segment from an included header file
</p>
<div class="code"><pre>
/*! This is describing class Shape
\author Bob
*/
class Shape {
public:
Shape() {
nshapes++;
}
virtual ~Shape() {
nshapes--;
};
double x, y; /*!&lt; Important Variables */
void move(double dx, double dy); /*!&lt; Moves the Shape */
virtual double area(void) = 0; /*!&lt; \return the area */
virtual double perimeter(void) = 0; /*!&lt; \return the perimeter */
static int nshapes;
};
</pre></div>
<p>
Simply running SWIG should result in the following code being present in Shapes.py
</p>
<div class="targetlang"><pre>
...
class Shape(_object):
"""
This is describing class Shape
Authors:
Bob
"""
...
def move(self, *args):
"""
Moves the Shape
"""
return _Shapes.Shape_move(self, *args)
def area(self):
"""
Return:
the area
"""
return _Shapes.Shape_area(self)
def perimeter(self):
"""
Return:
the perimeter
"""
return _Shapes.Shape_perimeter(self)
</pre></div>
<p>
If any parameters of a function or a method are documented in the Doxygen comment,
their description is copied into the generated output using
<a href="http://sphinx-doc.org/">Sphinx </a> documentation conventions. For example
</p>
<div class="code"><pre>
/**
Set a breakpoint at the given location.
@param filename The full path to the file.
@param line_number The line number in the file.
*/
bool SetBreakpoint(const char* filename, int line_number);
</pre></div>
<p>
would be translated to
</p>
<div class="targetlang"><pre>
def SetBreakpoint(filename, line_number):
r"""
Set a breakpoint at the given location.
:type filename: string
:param filename: The full path to the file.
:type line_number: int
:param line_number: The line number in the file.
"""
</pre></div>
<p>
The types used for the parameter documentation come from the "doctype" typemap which
is defined for all the primitive types and a few others (e.g. <tt>std::string</tt> and
<tt>shared_ptr&lt;T&gt;</tt>) but for non-primitive types is taken to be just the C++
name of the type with namespace scope delimiters (<tt>::</tt>) replaced with a dot. To
change this, you can define your own typemaps for the custom types, e.g:
</p>
<div class="code"><pre>
%typemap(doctype) MyDate "datetime.date";
</pre></div>
<p>
Currently Doxygen comments assigned to global variables and static member variables
are not present in generated code, so they have no comment translated for them.
</p>
<p>
<b>Whitespace and tables</b>
Whitespace is preserved when translating comments, so it makes
sense to have Doxygen comments formatted in a readable way. This
includes tables, where tags &lt;th&gt;, &lt;td&gt; and &lt;/tr&gt;are translated
to '|'. The line after line with &lt;th&gt; tags contains dashes.
If we take care about whitespace, comments in Python are much more
readable. Example:
<div class="code"><pre>
/**
* &lt;table border = '1'&gt;
* &lt;caption&gt;Animals&lt;/caption&gt;
* &lt;tr&gt;&lt;th&gt; Column 1 &lt;/th&gt;&lt;th&gt; Column 2 &lt;/th&gt;&lt;/tr&gt;
* &lt;tr&gt;&lt;td&gt; cow &lt;/td&gt;&lt;td&gt; dog &lt;/td&gt;&lt;/tr&gt;
* &lt;tr&gt;&lt;td&gt; cat &lt;/td&gt;&lt;td&gt; mouse &lt;/td&gt;&lt;/tr&gt;
* &lt;tr&gt;&lt;td&gt; horse &lt;/td&gt;&lt;td&gt; parrot &lt;/td&gt;&lt;/tr&gt;
* &lt;/table&gt;
*/
</pre></div>
<p>
translates to Python as:
</p>
<div class="diagram"><pre>
Animals
| Column 1 | Column 2 |
-----------------------
| cow | dog |
| cat | mouse |
| horse | parrot |
</pre></div>
<p>
<b>Overloaded functions</b>
Since all the overloaded functions in c++ are wrapped into one Python
function, Pydoc translator will combine every comment of every
overloaded function and put it into the comment for the one wrapper function.
</p>
<p>
If you intend to use resulting generated Python file with the Doxygen docs
generator, rather than Pydoc, you may want to turn off translation
completely (doxygen:notranslate feature). Then SWIG will just copy
the comments to the proxy file and reformat them if needed, but all
the comment content will be left as is. As Doxygen doesn't support
special commands in Python comments
(see <a href="http://www.doxygen.nl/manual/docblocks.html#pythonblocks">Doxygen
docs</a>), you may want to use some tool like doxypy
(<a href="https://pypi.org/project/doxypy/">doxypy</a>)
to do the work.
</p>
<H3><a name="Doxygen_pydoc_tags">17.4.2 Pydoc translator</a></H3>
<p>
Here is the list of all Doxygen tags and the description of how they are translated to Pydoc
</p>
<div class="diagram">
<table border="0" summary="Python Doxygen tags">
<tr>
<th align="left">Doxygen tags</th>
</tr>
<tr>
<td>\a</td>
<td>wrapped with '*'</td>
</tr>
<tr>
<td>\arg</td>
<td>prepended with '* '</td>
</tr>
<tr>
<td>\author</td>
<td>prints 'Author:'</td>
</tr>
<tr>
<td>\authors</td>
<td>prints 'Authors:'</td>
</tr>
<tr>
<td>\b</td>
<td>wrapped with '**'</td>
</tr>
<td>\c</td>
<td>wrapped with '``'</td>
</tr>
<tr>
<td>\cite</td>
<td>wrapped with single quotes</td>
</tr>
<tr>
<td>\code</td>
<td>replaced with '.. code-block:: c++'</td>
</tr>
<tr>
<td>\code{&lt;ext&gt;}</td>
<td>replaced with '.. code-block:: &lt;lang&gt;', where the following doxygen code languages are recognized: .c -&gt; C, .py -&gt; python, .java &gt; java</td>
</tr>
<tr>
<td>\cond</td>
<td>translated to 'Conditional comment: &lt;condition&gt;'</td>
</tr>
<tr>
<td>\copyright</td>
<td>prints 'Copyright:'</td>
</tr>
<tr>
<td>\deprecated</td>
<td>prints 'Deprecated:'</td>
</tr>
<tr>
<td>\e</td>
<td>wrapped with '*'</td>
</tr>
<tr>
<td>\else</td>
<td>replaced with '}Else:{'</td>
</tr>
<tr>
<td>\elseif</td>
<td>replaced with '}Else if: &lt;condition&gt;{'</td>
</tr>
<tr>
<td>\em</td>
<td>wrapped with '*'</td>
</tr>
<tr>
<td>\endcond</td>
<td>replaced with 'End of conditional comment.'</td>
</tr>
<tr>
<td>\endif</td>
<td>replaced with '}'</td>
</tr>
<tr>
<td>\example</td>
<td>replaced with 'Example:'</td>
</tr>
<tr>
<td>\exception</td>
<td>replaced with ':raises:'</td>
</tr>
<tr>
<td>\f$</td>
<td>rendered using ':math:``'</td>
</tr>
<tr>
<td>\f[</td>
<td>rendered using '.. math::'</td>
</tr>
<tr>
<td>\f{</td>
<td>rendered using '.. math::'</td>
</tr>
<tr>
<td>\if</td>
<td>replaced with 'If: &lt;condition&gt; {'</td>
</tr>
<tr>
<td>\ifnot</td>
<td>replaced with 'If not: &lt;condition&gt; {'</td>
</tr>
<tr>
<td>\li</td>
<td>prepended with '* '</td>
</tr>
<tr>
<td>\n</td>
<td>replaced with newline char</td>
</tr>
<tr>
<td>\note</td>
<td>replaced with 'Note:'</td>
</tr>
<tr>
<td>\overload</td>
<td>prints 'This is an overloaded ...' according to Doxygen docs</td>
</tr>
</tr>
<td>\p</td>
<td>wrapped with '``'</td>
</tr>
<tr>
<td>\par</td>
<td>replaced with 'Title: ...'</td>
</tr>
<tr>
<td>\param</td>
<td>add ':type:' and ':param:' directives</td>
</tr>
<tr>
<td>\param[&lt;dir&gt;]</td>
<td>same as \param, but direction ('in'; 'out'; 'in,out') is included in ':type:' directive</td>
</tr>
<tr>
<td>\remark</td>
<td>replaced with 'Remarks:'</td>
</tr>
<tr>
<td>\remarks</td>
<td>replaced with 'Remarks:'</td>
</tr>
<tr>
<td>\result</td>
<td>add ':rtype:' and ':return:' directives</td>
</tr>
<tr>
<td>\return</td>
<td>add ':rtype:' and ':return:' directives</td>
</tr>
<tr>
<td>\returns</td>
<td>add ':rtype:' and ':return:' directives</td>
</tr>
<tr>
<td>\sa</td>
<td>replaced with 'See also:'</td>
</tr>
<tr>
<td>\see</td>
<td>replaced with 'See also:'</td>
</tr>
<tr>
<td>\since</td>
<td>replaced with 'Since:'</td>
</tr>
<tr>
<td>\throw</td>
<td>replaced with ':raises:'</td>
</tr>
<tr>
<td>\throws</td>
<td>replaced wih ':raises:'</td>
</tr>
<tr>
<td>\todo</td>
<td>replaced with 'TODO:'</td>
</tr>
<tr>
<td>\tparam</td>
<td>add ':type:' and ':param:' directives</td>
</tr>
<tr>
<td>\verbatim</td>
<td>content copied verbatim</td>
</tr>
<tr>
<td>\version</td>
<td>replaced with 'Version:'</td>
</tr>
<tr>
<td>\warning</td>
<td>translated to 'Warning:'</td>
</tr>
<tr>
<td>\$</td>
<td>prints $ char</td>
</tr>
<tr>
<td>\@</td>
<td>prints @ char</td>
</tr>
<tr>
<td>\\</td>
<td>prints \ char</td>
</tr>
<tr>
<td>\&amp;</td>
<td>prints &amp; char</td>
</tr>
<tr>
<td>\~</td>
<td>prints ~ char</td>
</tr>
<tr>
<td>\&lt;</td>
<td>prints &lt; char</td>
</tr>
<tr>
<td>\&gt;</td>
<td>prints &gt; char</td>
</tr>
<tr>
<td>\#</td>
<td>prints # char</td>
</tr>
<tr>
<td>\%</td>
<td>prints % char</td>
</tr>
<tr>
<td>\&quot;</td>
<td>prints &quot; char</td>
</tr>
<tr>
<td>\.</td>
<td>prints . character</td>
</tr>
<tr>
<td>\::</td>
<td>prints ::</td>
</tr>
</table>
</div>
<H3><a name="Doxygen_python_unsupported_tags">17.4.3 Unsupported tags</a></H3>
<p>
Doxygen has a wealth of tags such as @latexonly that have no
equivalent in Pydoc. As a result several tags that have no
translation (or particular use, such as some linking and section tags)
are suppressed with their content just printed out (if it has any
sense, typically text content).
Here is the list of these tags:
</p>
<div class="diagram">
<b>Unsupported Python Doxygen tags</b>
<ul style="list-style-type:none;column-count:4;">
<li>\addindex</li>
<li>\addtogroup</li>
<li>\anchor</li>
<li>\attention</li>
<li>\brief</li>
<li>\bug</li>
<li>\callergraph</li>
<li>\callgraph</li>
<li>\category</li>
<li>\class</li>
<li>\copybrief</li>
<li>\copydetails</li>
<li>\copydoc</li>
<li>\date</li>
<li>\def</li>
<li>\defgroup</li>
<li>\details</li>
<li>\dir</li>
<li>\dontinclude</li>
<li>\dot</li>
<li>\dotfile</li>
<li>\enddot</li>
<li>\endhtmlonly</li>
<li>\endinternal</li>
<li>\endlatexonly</li>
<li>\endlink</li>
<li>\endmanonly</li>
<li>\endmsc</li>
<li>\endrtfonly</li>
<li>\endxmlonly</li>
<li>\enum</li>
<li>\extends</li>
<li>\file</li>
<li>\fn</li>
<li>\headerfile</li>
<li>\hideinitializer</li>
<li>\htmlinclude</li>
<li>\htmlonly</li>
<li>\image</li>
<li>\implements</li>
<li>\include</li>
<li>\includelineno</li>
<li>\ingroup</li>
<li>\interface</li>
<li>\internal</li>
<li>\invariant</li>
<li>\latexonly</li>
<li>\line</li>
<li>\link</li>
<li>\mainpage</li>
<li>\manonly</li>
<li>\memberof</li>
<li>\msc</li>
<li>\mscfile</li>
<li>\name</li>
<li>\namespace</li>
<li>\nosubgrouping</li>
<li>\package</li>
<li>\page</li>
<li>\paragraph</li>
<li>\post</li>
<li>\pre</li>
<li>\private</li>
<li>\privatesection</li>
<li>\property</li>
<li>\protected</li>
<li>\protectedsection</li>
<li>\protocol</li>
<li>\public</li>
<li>\publicsection</li>
<li>\ref</li>
<li>\related</li>
<li>\relatedalso</li>
<li>\relates</li>
<li>\relatesalso</li>
<li>\retval</li>
<li>\rtfonly</li>
<li>\section</li>
<li>\short</li>
<li>\showinitializer</li>
<li>\skip</li>
<li>\skipline</li>
<li>\snippet</li>
<li>\struct</li>
<li>\subpage</li>
<li>\subsection</li>
<li>\subsubsection</li>
<li>\tableofcontents</li>
<li>\test</li>
<li>\typedef</li>
<li>\union</li>
<li>\until</li>
<li>\var</li>
<li>\verbinclude</li>
<li>\weakgroup</li>
<li>\xmlonly</li>
<li>\xrefitem</li>
</ul>
</div>
<H3><a name="Doxygen_python_further_details">17.4.4 Further details</a></H3>
<p>
TO BE ADDED.
</p>
<H2><a name="Doxygen_troubleshooting">17.5 Troubleshooting</a></H2>
<p>
When running SWIG with command line option <tt>-doxygen</tt>, it may happen
that SWIG will fail to parse the code, which is valid C++ code and
is parsed without problems without the option. The problem is,
that Doxygen comments are not tokens (the C/C++ compiler actually never
sees them) and that they can appear anywhere in the code. That's why it is
practically impossible to handle all corner cases with the parser.
However, these problems can usually be avoided by minor changes in the
code or comment. Known problems and solutions are shown in this section.
</p>
<p>
Recommended approach is to first run SWIG without command line
option <tt>-doxygen</tt>. When it successfully processes the code,
include the option and fix problems with Doxygen comments.
</p>
<H3><a name="troubleshooting_ifndef">17.5.1 Problem with conditional compilation</a></H3>
<p>
Inserting a conditional compilation preprocessor directive between a
Doxygen comment and a commented item may break parsing:
</p>
<div class="code"><pre>
class A {
/**
* Some func.
*/
<font color='#ff0000'>#ifndef SWIG</font>
void myfunc()
{
}
#endif
};
</pre></div>
<p>
The solution is to move the directive above the comment:
</p>
<div class="code"><pre>
class A {
<font color='#00d000'>#ifndef SWIG</font>
/**
* Some func.
*/
void myfunc()
{
}
#endif
};
</pre></div>
<H2><a name="Doxygen_developer_details">17.6 Developer information</a></H2>
<p>
This section contains information for developers enhancing the Doxygen translator.
</p>
<H3><a name="Doxygen_translator_design">17.6.1 Doxygen translator design</a></H3>
<p>
If this functionality is turned on, SWIG places all comments found
into the SWIG parse tree. Nodes contain an additional attribute
called <tt>doxygen</tt> when a comment is present. Individual nodes
containing Doxygen with Structural Indicators, such as @file, as their
first command, are also present in the parse tree. These individual
"blobs" of Doxygen such as :
</p>
<div class="code"><pre>
/*! This is describing function Foo
\param x some random variable
\author Bob
\return Foo
*/
</pre></div>
<p>
are passed on individually to the Doxygen Translator module. This
module builds its own private parse tree and hands it to a separate
class for translation into the target documentation language. For
example, <tt>JavaDocConverter</tt> is the Javadoc module class.
</p>
<H3><a name="Doxygen_debugging_commands">17.6.2 Debugging the Doxygen parser and translator</a></H3>
<p>
There are two handy command line options, that enable lots of
detailed debug information printing.
</p>
<div class="shell"><pre>
-debug-doxygen-parser - Display Doxygen parser module debugging information
-debug-doxygen-translator - Display Doxygen translator module debugging information
</pre></div>
<H3><a name="Doxygen_tests">17.6.3 Tests</a></H3>
<p>
Doxygen tests have been added to the regular SWIG test-suite.
There are a number of tests beginning <tt>doxygen_</tt> in the Examples/test-suite sub-directory.
</p>
<p>
Like any other SWIG test case, the tests are included in Examples/test-suite/common.mk and can be tested with
commands like <tt>make check-test-suite</tt> or <tt>make check-python-test-suite</tt>.
To run them individually, type
<tt>make -s &lt;testname&gt;.cpptest</tt> in the language-specific sub-directory in
<tt>Examples/test-suite</tt> directory. For example:
</p>
<div class="shell"><pre>
Examples/test-suite/java $ make -s doxygen_parsing.cpptest
</pre></div>
<p>
If the test fails, both expected and translated comments are printed to
std out, but also written to files <i>expected.txt</i>
and <i>got.txt</i>. Since it is often difficult to find a single
character difference in several lines of text, we can use some diff
tool, for example:
</p>
<div class="shell"><pre>
Examples/test-suite/java $ kdiff3 expected.txt got.txt
</pre></div>
<p>
Runtime tests in Java are implemented using Javadoc doclets. To make that work, you
should have tools.jar from the JDK in your classpath. Or you should have JAVA_HOME
environment variable defined and pointing to the JDK location.
</p>
<p>
The Java's comment parsing code (the testing part) is located in commentParser.java.
It checks the generated code. It is possible
to run this file as a stand-alone program, with <tt>java commentParser &lt;some java package&gt;</tt>,
and it will print the list of comments found in the specified directory (in the format it has used
in the runtime tests). So, when you want to create a new Doxygen test case,
just copy an existing one and replace the actual comment content (section of entries in
form 'wantedComments.put(...)' with the output of the above command.
</p>
<p>
Runtime tests in Python are just plain string comparisons of the __doc__
properties.
</p>
<H2><a name="Doxygen_language_extension">17.7 Extending to other languages</a></H2>
<p>
In general, an extension to another language requires a fairly deep understanding of the target language module, such as Modules/python.cxx for Python.
Searching for "doxygen" in the java.cxx module can give you a good idea of the process for placing documentation comments into the correct areas.
The basic gist is that anywhere a comment may reside on a node, there needs to be a catch for it in front of where that function, class, or other object is written out to a target language file.
The other half of extension is building a target documentation language comment generator that handles one blob at a time.
However, this is relatively simple and nowhere near as complex as the wrapper generating modules in SWIG.
See Source/Doxygen/javadoc.cxx for a good example.
The target language module passes the Doxygen Translator the blob to translate, and receives back the translated text.
</p>
<p>
<b> What is given to the Doxygen Translator</b>
</p>
<div class="code"><pre>
/*! This is describing function Foo
\param x some random variable
\author Bob
\return Foo
*/
</pre></div>
<p>
<b> What is received back by java.cxx </b>
</p>
<div class="targetlang"><pre>
/** This is describing function Foo
*
* @param x some random variable
* @author Bob
* @return Foo
*/
</pre></div>
<p> Development of the comment translator itself is simplified by the fact that the Doxygen Translator module can easily include a <tt>main</tt> function and thus be developed, compiled, and tested independently of SWIG.
</p>
</body>
</html>