= Wiki Processors =

Processors are WikiMacros designed to provide alternative markup formats for the [TracWiki Wiki engine]. Processors can be thought of as ''macro functions to process user-edited text''. 

The Wiki engine uses processors for various different purposes, 
and can be used in any Wiki text throughout Trac, for:
 - [#CodeHighlightingSupport syntax highlighting] or for rendering text verbatim
 - rendering [#HTMLrelated Wiki markup inside a context], 
   like <div> blocks or <span>, or within <td> or <th> table cells
 - using an alternative markup syntax, like [wiki:WikiHtml raw HTML] and
   [wiki:WikiRestructuredText Restructured Text],
   or [http://www.textism.com/tools/textile/ textile]


== Using Processors ==

To use a processor on a block of text, first delimit the lines using
a Wiki ''code block'':
{{{
{{{
The lines
that should be processed...
}}}
}}}

Immediately after the `{{{` or on the line just below, 
add `#!` followed by the ''processor name''.

{{{
{{{
#!processorname
The lines
that should be processed...
}}}
}}}

This is the "shebang" notation, familiar to most UNIX users.

Besides their content, some Wiki processors can also accept ''parameters'',
which are then given as `key=value` pairs after the processor name, 
on the same line. If `value` has to contain space, as it's often the case for
the style parameter, a quoted string can be used (`key="value with space"`).

Note that some processors are meant to process Wiki markup,
so in this case it's quite possible to ''nest'' processor blocks.
You may indent the content of nested blocks for increased clarity,
this extra indentation will be ignore when processing the content.


== Examples ==

||= Wiki Markup =||= Display =||
{{{#!td colspan=2 align=center style="border: none"

                __Example 1__: Inserting raw HTML
}}}
|-----------------------------------------------------------------
{{{#!td style="border: none"
{{{
#!html
<pre class="wiki">{{{
#!html
&lt;h1 style="color: grey"&gt;This is raw HTML&lt;/h1&gt;
}}}</pre>
}}}
}}}
{{{#!td valign=top style="border: none; padding-left: 2em"
{{{
#!html
<h1 style="color: grey">This is raw HTML</h1>
}}}
}}}
|-----------------------------------------------------------------
{{{#!td colspan=2 align=center style="border: none"

     __Example 2__: Highlighted Python code in a <div> block with custom style
}}}
|-----------------------------------------------------------------
{{{#!td style="border: none"
  {{{
  {{{#!div style="background: #ffd; border: 3px ridge"

  This is an example of embedded "code" block:

    {{{
    #!python
    def hello():
        return "world"
    }}}

  }}}
  }}}
}}}
{{{#!td valign=top style="border: none; padding: 1em"
  {{{#!div style="background: #ffd; border: 3px ridge"

  This is an example of embedded "code" block:

    {{{
    #!python
    def hello():
        return "world"
    }}}

  }}}
}}}

Note already at this point that HTML blocks have to be self-contained, 
i.e. you can't start an HTML element in one block and close it later in a second block. Use [#element element] processors for achieving a similar effect. 
More details on this in WikiHtml.


== Available Processors ==

The following processors are included in the Trac distribution:

 `#!default` :: Present the text verbatim in a preformatted text block. 
                This is the same as specifying ''no'' processor name
                (and no `#!`)
 `#!comment` :: Do not process the text in this section (i.e. contents exist
                only in the plain text - not in the rendered page).

=== HTML related ===

 `#!html`        :: Insert custom HTML in a wiki page.
 `#!htmlcomment` :: Insert an HTML comment in a wiki page (''since 0.12'').

  `#!div` :: Wrap an arbitrary Wiki content inside a <div> element
             (''since 0.11'').
 `#!span` :: Wrap an arbitrary Wiki content inside a <span> element 
             (''since 0.11''). 

 `#!td` :: Wrap an arbitrary Wiki content inside a <td> element (''since 0.12'')
 `#!th` :: Wrap an arbitrary Wiki content inside a <th> element (''since 0.12'') 
 `#!tr` :: Can optionally be used for wrapping `#!td` and `#!th` blocks,
       either for specifying row attributes of better visual grouping
       (''since 0.12'')

See WikiHtml for more details about these processors.

=== Other Markups ===

     `#!rst` :: Trac support for Restructured Text. See WikiRestructuredText.
 `#!textile` :: Supported if [http://cheeseshop.python.org/pypi/textile Textile] 
                is installed. 
                See [http://www.textism.com/tools/textile/ a Textile reference].


=== Code Highlighting Support ===

Trac includes processors to provide inline syntax highlighting:
 `#!c` (C), `#!cpp` (C++), `#!python` (Python), `#!perl` (Perl), 
 `#!ruby` (Ruby), `#!php` (PHP), `#!asp` (ASP), `#!java` (Java), 
 `#!js` (Javascript), `#!sql (SQL)`, `#!xml` (XML or highlighted HTML),
 `#!sh` (Bourne/Bash shell), etc.

Trac relies on external software packages for syntax coloring,
like [http://pygments.org Pygments]. 

See TracSyntaxColoring for informations about which languages
are supported and how to enable support for more languages.

Note also that by using the MIME type as processor, it is possible to syntax-highlight the same languages that are supported when browsing source code. For example, you can write:
{{{
{{{
#!text/html
<h1>text</h1>
}}}
}}}

The result will be syntax highlighted HTML code:
{{{
#!text/html
<h1>text</h1>
}}}

The same is valid for all other mime types supported.

=== Additional Processors ===
For more processor macros developed and/or contributed by users, visit: 
 * [trac:ProcessorBazaar]
 * [trac:MacroBazaar]
 * [th:WikiStart Trac Hacks] community site

Developing processors is no different from Wiki macros. 
In fact they work the same way, only the usage syntax differs. 
See WikiMacros#DevelopingCustomMacros for more information.


----
See also: WikiMacros, WikiHtml, WikiRestructuredText, TracSyntaxColoring, WikiFormatting, TracGuide