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1= Trac Macros =
2
3[[PageOutline]]
4
5Trac macros are plugins to extend the Trac engine with custom 'functions' written in Python. A macro inserts dynamic HTML data in any context supporting WikiFormatting. Its syntax is `[[macro-name(optional-arguments)]]`.
6
7The WikiProcessors are another kind of macros. They typically deal with alternate markup formats and transformation of larger "blocks" of information (like source code highlighting). They are used for processing the multiline `{{{#!wiki-processor-name ... }}}` blocks.
8
9== Using Macros ==
10
11Macro calls are enclosed in two ''square brackets''. Like Python functions, macros can also have arguments, a comma separated list within parentheses.
12
13=== Getting Detailed Help ===
14The list of available macros and the full help can be obtained using the !MacroList macro, as seen [#AvailableMacros below].
15
16A brief list can be obtained via `[[MacroList(*)]]` or `[[?]]`.
17
18Detailed help on a specific macro can be obtained by passing it as an argument to !MacroList, e.g. `[[MacroList(MacroList)]]`, or, more conveniently, by appending a question mark (`?`) to the macro's name, like in `[[MacroList?]]`.
19
20
21
22=== Example ===
23
24A list of 3 most recently changed wiki pages starting with 'Trac':
25
26||= Wiki Markup =||= Display =||
27{{{#!td
28  {{{
29  [[RecentChanges(Trac,3)]]
30  }}}
31}}}
32{{{#!td style="padding-left: 2em;"
33[[RecentChanges(Trac,3)]]
34}}}
35|-----------------------------------
36{{{#!td
37  {{{
38  [[RecentChanges?(Trac,3)]]
39  }}}
40}}}
41{{{#!td style="padding-left: 2em;"
42[[RecentChanges?(Trac,3)]]
43}}}
44|-----------------------------------
45{{{#!td
46  {{{
47  [[?]]
48  }}}
49}}}
50{{{#!td style="padding-left: 2em"
51{{{#!html
52<div style="font-size: 80%" class="trac-macrolist">
53<h3><code>[[Image]]</code></h3>Embed an image in wiki-formatted text.
54
55The first argument is the file …
56<h3><code>[[InterTrac]]</code></h3>Provide a list of known <a class="wiki" href="/wiki/InterTrac">InterTrac</a> prefixes.
57<h3><code>[[InterWiki]]</code></h3>Provide a description list for the known <a class="wiki" href="/wiki/InterWiki">InterWiki</a> prefixes.
58<h3><code>[[KnownMimeTypes]]</code></h3>List all known mime-types which can be used as <a class="wiki" href="/wiki/WikiProcessors">WikiProcessors</a>.
59Can be …</div>
60}}}
61etc.
62}}}
63
64== Available Macros ==
65
66''Note that the following list will only contain the macro documentation if you've not enabled `-OO` optimizations, or not set the `PythonOptimize` option for [wiki:TracModPython mod_python].''
67
68[[MacroList]]
69
70== Macros from around the world ==
71
72The [http://trac-hacks.org/ Trac Hacks] site provides a wide collection of macros and other Trac [TracPlugins plugins] contributed by the Trac community. If you're looking for new macros, or have written one that you'd like to share with the world, please don't hesitate to visit that site.
73
74== Developing Custom Macros ==
75Macros, like Trac itself, are written in the [http://python.org/ Python programming language] and are developed as part of TracPlugins.
76
77For more information about developing macros, see the [trac:TracDev development resources] on the main project site.
78
79
80Here are 2 simple examples showing how to create a Macro with Trac 0.11.
81
82Also, have a look at [trac:source:tags/trac-0.11/sample-plugins/Timestamp.py Timestamp.py] for an example that shows the difference between old style and new style macros and at the [trac:source:tags/trac-0.11/wiki-macros/README macros/README] which provides a little more insight about the transition.
83
84=== Macro without arguments ===
85To test the following code, you should saved it in a `timestamp_sample.py` file located in the TracEnvironment's `plugins/` directory.
86{{{
87#!python
88from datetime import datetime
89# Note: since Trac 0.11, datetime objects are used internally
90
91from genshi.builder import tag
92
93from trac.util.datefmt import format_datetime, utc
94from trac.wiki.macros import WikiMacroBase
95
96class TimeStampMacro(WikiMacroBase):
97    """Inserts the current time (in seconds) into the wiki page."""
98
99    revision = "$Rev$"
100    url = "$URL$"
101
102    def expand_macro(self, formatter, name, text):
103        t = datetime.now(utc)
104        return tag.b(format_datetime(t, '%c'))
105}}}
106
107=== Macro with arguments ===
108To test the following code, you should saved it in a `helloworld_sample.py` file located in the TracEnvironment's `plugins/` directory.
109{{{
110#!python
111from genshi.core import Markup
112
113from trac.wiki.macros import WikiMacroBase
114
115class HelloWorldMacro(WikiMacroBase):
116    """Simple HelloWorld macro.
117
118    Note that the name of the class is meaningful:
119     - it must end with "Macro"
120     - what comes before "Macro" ends up being the macro name
121
122    The documentation of the class (i.e. what you're reading)
123    will become the documentation of the macro, as shown by
124    the !MacroList macro (usually used in the WikiMacros page).
125    """
126
127    revision = "$Rev$"
128    url = "$URL$"
129
130    def expand_macro(self, formatter, name, text, args):
131        """Return some output that will be displayed in the Wiki content.
132
133        `name` is the actual name of the macro (no surprise, here it'll be
134        `'HelloWorld'`),
135        `text` is the text enclosed in parenthesis at the call of the macro.
136          Note that if there are ''no'' parenthesis (like in, e.g.
137          [[HelloWorld]]), then `text` is `None`.
138        `args` are the arguments passed when HelloWorld is called using a
139        `#!HelloWorld` code block.
140        """
141        return 'Hello World, text = %s, args = %s' % \
142            (Markup.escape(text), Markup.escape(repr(args)))
143
144}}}
145
146Note that `expand_macro` optionally takes a 4^th^ parameter ''`args`''. When the macro is called as a [WikiProcessors WikiProcessor], it's also possible to pass `key=value` [WikiProcessors#UsingProcessors processor parameters]. If given, those are stored in a dictionary and passed in this extra `args` parameter. On the contrary, when called as a macro, `args` is  `None`. (''since 0.12'').
147
148For example, when writing:
149{{{
150{{{#!HelloWorld style="polite" -silent verbose
151<Hello World!>
152}}}
153
154{{{#!HelloWorld
155<Hello World!>
156}}}
157
158[[HelloWorld(<Hello World!>)]]
159}}}
160One should get:
161{{{
162Hello World, text = <Hello World!> , args = {'style': u'polite', 'silent': False, 'verbose': True}
163Hello World, text = <Hello World!> , args = {}
164Hello World, text = <Hello World!> , args = None
165}}}
166
167Note that the return value of `expand_macro` is '''not''' HTML escaped. Depending on the expected result, you should escape it by yourself (using `return Markup.escape(result)`) or, if this is indeed HTML, wrap it in a Markup object (`return Markup(result)`) with `Markup` coming from Genshi, (`from genshi.core import Markup`). 
168
169You can also recursively use a wiki Formatter (`from trac.wiki import Formatter`) to process the `text` as wiki markup, for example by doing:
170
171{{{
172#!python
173from genshi.core import Markup
174from trac.wiki.macros import WikiMacroBase
175from trac.wiki import Formatter
176import StringIO
177
178class HelloWorldMacro(WikiMacroBase):
179        def expand_macro(self, formatter, name, text, args):
180                text = "whatever '''wiki''' markup you want, even containing other macros"
181                # Convert Wiki markup to HTML, new style
182                out = StringIO.StringIO()
183                Formatter(self.env, formatter.context).format(text, out)
184                return Markup(out.getvalue())
185}}}
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