# 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*.

Wiki processors can be used in any Wiki text throughout Trac, such as:

    - [#CodeHighlightingSupport syntax highlighting] or for rendering text verbatim
    - rendering [#HTMLrelated Wiki markup inside a context], like inside <div> blocks or <span> or within <td> or <th> table cells
    - using an alternative markup syntax, like [raw HTML] and [WikiRestructuredText Restructured Text] or [http://www.textism.com/tools/textile/ textile](WikiHtml)


## 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 and 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"`).

As some processors are meant to process Wiki markup, it's quite possible to *nest* processor blocks.
You may want to indent the content of nested blocks for increased clarity, this extra indentation will be ignored 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
<h1 style="color: grey">This is raw HTML</h1>
```
```
```
```#!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"
    ```

  ```
```
|-----------------------------------------------------------------
```#!td colspan=2 align=center style="border: none"

     __Example 3__: Searching tickets from a wiki page, by keywords.
```
|-----------------------------------------------------------------
```#!td style="border: none"
  ```
  ```
  #!html
  <form action="/query" method="get"><div>
  <input type="text" name="keywords" value="~" size="30"/>
  <input type="submit" value="Search by Keywords"/>
  <!-- To control what fields show up use hidden fields
  <input type="hidden" name="col" value="id"/>
  <input type="hidden" name="col" value="summary"/>
  <input type="hidden" name="col" value="status"/>
  <input type="hidden" name="col" value="milestone"/>
  <input type="hidden" name="col" value="version"/>
  <input type="hidden" name="col" value="owner"/>
  <input type="hidden" name="col" value="priority"/>
  <input type="hidden" name="col" value="component"/>
  -->
  </div></form>
  ```
  ```
```
```#!td valign=top style="border: none; padding: 1em"
  ```
  #!html
  <form action="/query" method="get"><div>
  <input type="text" name="keywords" value="~" size="30"/>
  <input type="submit" value="Search by Keywords"/>
  <!-- To control what fields show up use hidden fields
  <input type="hidden" name="col" value="id"/>
  <input type="hidden" name="col" value="summary"/>
  <input type="hidden" name="col" value="status"/>
  <input type="hidden" name="col" value="milestone"/>
  <input type="hidden" name="col" value="version"/>
  <input type="hidden" name="col" value="owner"/>
  <input type="hidden" name="col" value="priority"/>
  <input type="hidden" name="col" value="component"/>
  -->
  </div></form>
  ```
```

## 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. |
| **`#rtl`** | Introduce a Right-To-Left block with appropriate CSS direction and styling. *(since 0.12.2)* |
|| |
|| **[=#HTMLrelated HTML related]** |
| **`#html`** | Insert custom HTML in a wiki page. |
| **`#htmlcomment`** | Insert an HTML comment in a wiki page. (*since 0.12*) |
| | Note 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 the following processors for achieving a similar effect.  |
| **`#div`** | Wrap wiki content inside a <div> element. |
| **`#span`** | Wrap wiki content inside a <span> element. |
| **`#td`** | Wrap wiki content inside a <td> element. (*since 0.12*) |
| **`#th`** | Wrap 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 or better visual grouping. (*since 0.12*) |
| **`#table`** | Can optionally be used for wrapping `#tr`, `#td` and `#th` blocks, for specifying table attributes. One current limitation however is that tables cannot be nested. (*since 0.12*) |
| | See WikiHtml for example usage and more details about these processors. |
|| |
|| **Other Markups** |
| **`#rst`** | Trac support for Restructured Text. See WikiRestructuredText. |
| **`#textile`** | Supported if [Textile] is installed. See [http://www.textism.com/tools/textile/ a Textile reference](http://cheeseshop.python.org/pypi/textile). |
|| |
|| **[=#CodeHighlightingSupport Code Highlighting Support]** |
| **`#c`** [**`#cpp`** (C++) [[BR]] **`#python`** [[BR]] **`#perl`** [[BR]] **`#ruby`** [[BR]] **`#php`** [[BR]] **`#asp`** [[BR]] **`#java`** [[BR]] **`#js`** (Javascript) [[BR]] **`#sql`** [[BR]] **`#xml`** (XML or HTML) [[BR]] **`#sh`** (Bourne/Bash shell) [[BR]] **etc.** [[BR]] | Trac includes processors to provide inline syntax highlighting for source code in various languages. [[BR]] [[BR]] Trac relies on [http://pygments.org Pygments] for syntax coloring. [[BR]] [[BR]]([BR]]) See TracSyntaxColoring for information about which languages are supported and how to enable support for more languages. |
|| |


Since 1.1.2 the default, coding highlighting and MIME-type processors support the argument `lineno` for adding line numbering to the code block. When a value is specified, as in `lineno=3`, the numbering will start at the specified value. When used in combination with the `lineno` argument, the `marks` argument is also supported for highlighting lines. A single line number, set of line numbers and range of line numbers are allowed. For example, `marks=3`, `marks=3-6`, `marks=3,5,7` and `marks=3-5,7` are all allowed. The specified values are relative to the numbered lines, so if `lineno=2` is specified to start the line numbering at 2, `marks=2` will result in the first line being highlighted.

Using the MIME type as processor, it is possible to syntax-highlight the same languages that are supported when browsing source code.

|| **MIME Type Processors** |
|---|---|
```#!tr
```#!td
Some examples:
 ```
```#!text/html
<h1>text</h1>

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

The same is valid for all other [TracSyntaxColoring#SyntaxColoringSupport mime types supported].
```
```
```#!td
 ```
```#!diff
--- Version 55
+++ Version 56
@@ -115,8 +115,9 @@
     name='TracHelloWorld', version='1.0',
     packages=find_packages(exclude=['*.tests*']),
-    entry_points = """
-        [trac.plugins]
-        helloworld = myplugs.helloworld
-    """,
+    entry_points = {
+        'trac.plugins': [
+            'helloworld = myplugs.helloworld',
+        ],
+    },
 )
```
 ```
```
```#!td
'''`#!diff`''' has a particularly nice renderer:
 ```#!diff
--- Version 55
+++ Version 56
@@ -115,8 +115,9 @@
     name='TracHelloWorld', version='1.0',
     packages=find_packages(exclude=['*.tests*']),
-    entry_points = """
-        [trac.plugins]
-        helloworld = myplugs.helloworld
-    """,
+    entry_points = {
+        'trac.plugins': [
+            'helloworld = myplugs.helloworld',
+        ],
+    },
 )
 ```
```

Line numbers can be added to code blocks and lines can be highlighted //(since 1.1.2)//.
```
```#!python lineno=3 marks=3,9-10,16
def expand_markup(stream, ctxt=None):
    """A Genshi stream filter for expanding `genshi.Markup` events.

    Note: Expansion may not be possible if the fragment is badly
    formed, or partial.
    """
    for event in stream:
        if isinstance(event[1], Markup):
            try:
                for subevent in HTML(event[1]):
                    yield subevent
            except ParseError:
                yield event
        else:
            yield event
```
```
```#!python lineno=3 marks=3,9-10,16
def expand_markup(stream, ctxt=None):
    """A Genshi stream filter for expanding `genshi.Markup` events.

    Note: Expansion may not be possible if the fragment is badly
    formed, or partial.
    """
    for event in stream:
        if isinstance(event[1], Markup):
            try:
                for subevent in HTML(event[1]):
                    yield subevent
            except ParseError:
                yield event
        else:
            yield event
```

For more processor macros developed and/or contributed by users, visit the [Trac Hacks](https://trac-hacks.org) 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