wiki:WikiMacros

Version 3 (modified by trac, 9 years ago) ( diff )

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Trac Macros

  1. Trac Macros
    1. Using Macros
      1. Getting Detailed Help
      2. Example
    2. Available Macros
    3. Macros from around the world
    4. Developing Custom Macros
      1. Macro without arguments
      2. Macro with arguments

Trac 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)]].

The 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.

Using Macros

Macro calls are enclosed in two square brackets [[..]]. Like Python functions, macros can also have arguments, a comma separated list within parentheses [[..(,)]].

Getting Detailed Help

The list of available macros and the full help can be obtained using the MacroList macro, as seen below.

A brief list can be obtained via [[MacroList(*)]] or [[?]].

Detailed 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?]].

Example

A list of the 3 most recently changed wiki pages starting with 'Trac':

Wiki Markup Display 
[[RecentChanges(Trac,3)]]

Nov 26, 2022

[[RecentChanges?(Trac,3)]]

[[RecentChanges]]

List all pages that have recently been modified, ordered by the time they were last modified.

This macro accepts two ordered arguments and a named argument. The named argument can be placed in any position within the argument list.

The first parameter is a prefix string: if provided, only pages with names that start with the prefix are included in the resulting list. If this parameter is omitted, all pages are included in the list.

The second parameter is the maximum number of pages to include in the list.

The group parameter determines how the list is presented:

group=date
The pages are presented in bulleted lists that are grouped by date (default).
group=none
The pages are presented in a single bulleted list.

Tip: if you only want to specify a maximum number of entries and don't want to filter by prefix, specify an empty first parameter, e.g. [[RecentChanges(,10,group=none)]]. 

[[?]]

[[Image]]

Embed an image in wiki-formatted text. The first argument is the file …

[[InterTrac]]

Provide a list of known InterTrac prefixes.

[[InterWiki]]

Provide a description list for the known InterWiki prefixes.

[[KnownMimeTypes]]

List all known mime-types which can be used as WikiProcessors. Can be …

etc.

Available Macros

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 mod_python.

[[BlogList]]

A macro to display list of posts and extracts outside (or inside) the Blog module - most commonly Wiki pages.

All arguments are optional: 

[[BlogList]]

Available named arguments:

  • recent= - max. number of posts
  • category= - a category
  • author= - an author
  • period= - time period of the format YYYY/MM
  • heading= - a heading for the list
  • format= - type of display (see below for details)
  • max_size= - max. number of characters to render for each post
  • meta= - use =off to hide date, author and categories (default 'on')

Example showing some available named arguments: 

[[BlogList(recent=5, max_size=250, period=2007/12, author=osimons, format=float, heading=Some Trac Posts)]]

The arguments for criteria are 'AND'-based, so the above example will render at most 5 posts by 'osimons' in December 2007.

There is no heading unless specified.

Without restriction on recent number of posts, it will use the number currently active in the Blog module as default for 'float' and 'full' rendering, but for rendering of 'inline' list it will render all found as default unless restricted. Additionally for 'float' and 'full' it will truncate content if it is larger than a max_size (if set).

The format= keyword argument supports rendering these formats:

format=inlineRenders an unordered list in the normal text flow (default).
format=floatA floating box out on the side of the page with slightly more detail.
format=fullFull rendering like on period, category and author listings inside blog.

The arguments can appear in any order.

Posts are rendered sorted by newest first for all modes.

[[ChangeLog]]

Write repository change log to output.

The ChangeLog macro writes a log of the last changes of a repository at a given path. Following variants are possible to use: 

1. [[ChangeLog([reponame:]path)]]
2. [[ChangeLog([reponame:]path@rev)]]
3. [[ChangeLog([reponame:]path@rev, limit)]]
4. [[ChangeLog([reponame:]path@from-to)]]
5. [[ChangeLog([reponame:]path, limit, rev)]]
  1. Default repository is used if reponame is left out. To show the last five changes of the default repository: 
    [[ChangeLog(/)]]
    To show the last five changes of the trunk folder in a named repo: 
    [[ChangeLog(otherrepo:/trunk)]]
  2. The ending revision can be set. To show the last five changes up to revision 99: 
    [[ChangeLog(otherrepo:/trunk@99)]]
  3. The limit can be set by an optional parameter. To show the last 10 changes, up to revision 99: 
    [[ChangeLog(otherrepo:/trunk@99, 10)]]
  4. A range of revisions can be logged. 
    [[ChangeLog(otherrepo:/trunk@90-99)]]
    To lists all changes: 
    [[ChangeLog(otherrepo:/trunk@1-HEAD)]]
    HEAD can be left out: 
    [[ChangeLog(otherrepo:/trunk@1-)]]
  5. For backwards compatibility, revision can be stated as a third parameter: 
    [[ChangeLog(otherrepo:/trunk, 10, 99)]]

limit and rev may be keyword arguments. 

[[ChangeLog(otherrepo:/trunk, limit=10, rev=99)]]

[[CommitTicketReference]]

Insert a changeset message into the output.

This macro must be called using wiki processor syntax as follows: 

{{{
#!CommitTicketReference repository="reponame" revision="rev"
}}}

where the arguments are the following:

  • repository: the repository containing the changeset
  • revision: the revision of the desired changeset

[[DiaVisView]]

Embed a Dia as an png image in wiki-formatted text. Will automatically convert a Dia to a png file. The first argument is the filename, after which the horizontal width can be given separated by a comma, as can other image parmaeters to position it. Will now also accept vdx format drawings, as well as compressed files.

One can select one or more layers with the layers parameter and a dot separated list, e.g. (DiaVisView(myfile, layers=0.1.2) (which shows only layers 0, 1, and 2.

Please see the image macro for more details on arguments.

Dia's output filter can be set in trac config thus:

[diavisview] output_filter = png-libart

Or even:

[diavisview] output_filter = svg extension = svg skip_width_check = true

Adapted from the Image.py macro created by Shun-ichi Goto <gotoh@…>

[[EasyPoll]]

EasyPoll: Fully featured Database driven poll plugin with permission controlls for voting and poll creation. Google charts for showing poll results. Description: The purpose of this plugin is to provide an easy way to integrate polls in Trac wiki and ticket pages. Easy poll uses mysql db for storing poll related data and uses google charts to show results of polls. Features:

  1. Response type: You can decide the response type for polls i.e whether you want single response poll(radio button poll) or multiple response poll(checkbox button poll).
  2. Google charts type: You can decide which type of chart you want to use for showing results.
  3. Poll options: Poll option can be any valid english string or any Ticket number(EasyPoll will fetch summary for ticket id given and use as a option text).
  4. Change vote: You can manage whether user can change their vote or not.

Sample Example:

[[EasyPoll( name = my first poll,

title = What's your favorite programming language?, response_type = single, options = Python : PHP : JAVA : C : Lisp, user_can_change_vote = false, chart_type = pie

)

]]

Attributes explanation:

  1. name(required) : name is used as a poll identifier, if you change the name value than it will be treated as new poll.

Nowhere in the poll the name will be shown. Don't change the name of the poll after poll creation

  1. title(required) : title will be used as a poll title. You can change it whenever you want. Each time the existing poll will be updated.
  2. options(required) : options should be separated by colon (:)

option can also have Ticket id as their option like options = #1 : #2 : #3 In this case the summary will be pulled out from the valid tickets and will be used as option text with ticket link.

  1. response(optional) : reponse can take two values (i) multiple and (ii) single. Default is (ii)single option

(i) multiple : multiple response type will generate poll with checkboxes, in this case user can choose multiple options. (ii) single : single reponse type will generate poll with radio buttons, in this case user can choose only one option

  1. user_can_change_vote(optional) : user_can_change_vote can take two values (i) false and (ii) true. Default is false

(i) false : once user cast their vote, they cannot change their vote, Poll will be disabled for them, however they can see poll results. (ii) true : user can change their vote anytime and many times. Poll will always be enabled for them and they can see poll results.

  1. chart_type(optional) : chart_type can take two values (i) pie and (ii) bar. Default is pie.

(i) pie : Pie chart will be used to show poll results. (ii) bar : Bar chart will be used to show poll results. User can see poll results only after casting their vote.

Permissions Explanation:

  1. EASYPOLL_CREATE : User who has EASYPOLL_CREATE or TRAC_ADMIN permission can create easy polls in wiki or ticket page.
  2. EASYPOLL_VOTE : User who has EASYPOLL_VOTE or TRAC_ADMIN permission can vote on easy polls in wiki or ticket page.

Every login user on Trac can see EasyPoll but can vote or create only if user has sufficient permissions.

Limitations:

  1. As of now only supports ascii characters.
  2. Don't use comma(,) while picking easy poll attributes. By design comma(,) is used as a attribute separator

[[Image]]

Embed an image in wiki-formatted text.

The first argument is the file specification. The file specification may reference attachments in three ways:

  • module:id:file, where module can be either wiki or ticket, to refer to the attachment named file of the specified wiki page or ticket.
  • id:file: same as above, but id is either a ticket shorthand or a Wiki page name.
  • file to refer to a local attachment named 'file'. This only works from within that wiki page or a ticket.

The file specification may also refer to:

  • repository files, using the source:file syntax (source:file@rev works also).
  • files, using direct URLs: /file for a project-relative, //file for a server-relative, or http://server/file for absolute location. An InterWiki prefix may be used.
  • embedded data using the ​rfc2397 data URL scheme, provided the URL is enclosed in quotes.

The remaining arguments are optional and allow configuring the attributes and style of the rendered <img> element:

  • digits and unit are interpreted as the size (ex. 120px, 25%) for the image
  • right, left, center, top, bottom and middle are interpreted as the alignment for the image (alternatively, the first three can be specified using align=... and the last three using valign=...)
  • link=some TracLinks... replaces the link to the image source by the one specified using a TracLinks. If no value is specified, the link is simply removed.
  • inline specifies that the content generated be an inline XHTML element. By default, inline content is not generated, therefore images won't be rendered in section headings and other one-line content.
  • nolink means without link to image source (deprecated, use link=)
  • key=value style are interpreted as HTML attributes or CSS style indications for the image. Valid keys are:
    • align, valign, border, width, height, alt, title, longdesc, class, margin, margin-(left,right,top,bottom), id and usemap
    • border, margin, and margin-* can only be a single number (units are pixels).
    • margin is superseded by center which uses auto margins

Examples: 

[[Image(photo.jpg)]]               # simplest
[[Image(photo.jpg, 120px)]]        # with image width size
[[Image(photo.jpg, right)]]        # aligned by keyword
[[Image(photo.jpg, nolink)]]       # without link to source
[[Image(photo.jpg, align=right)]]  # aligned by attribute

You can use an image from a wiki page, ticket or other module. 

[[Image(OtherPage:foo.bmp)]]    # from a wiki page
[[Image(base/sub:bar.bmp)]]     # from hierarchical wiki page
[[Image(#3:baz.bmp)]]           # from another ticket
[[Image(ticket:36:boo.jpg)]]    # from another ticket (long form)
[[Image(source:/img/bee.jpg)]]  # from the repository
[[Image(htdocs:foo/bar.png)]]   # from project htdocs dir
[[Image(shared:foo/bar.png)]]   # from shared htdocs dir (since 1.0.2)

Adapted from the Image.py macro created by Shun-ichi Goto <gotoh@…>

[[InterTrac]]

Provide a list of known InterTrac prefixes.

[[InterWiki]]

Provide a description list for the known InterWiki prefixes.

[[KnownMimeTypes]]

List all known mime-types which can be used as WikiProcessors.

Can be given an optional argument which is interpreted as mime-type filter.

[[MacroList]]

Display a list of all installed Wiki macros, including documentation if available.

Optionally, the name of a specific macro can be provided as an argument. In that case, only the documentation for that macro will be rendered.

Note that this macro will not be able to display the documentation of macros if the PythonOptimize option is enabled for mod_python!

[[PageOutline]]

Display a structural outline of the current wiki page, each item in the outline being a link to the corresponding heading.

This macro accepts four optional parameters:

  • The first is a number or range that allows configuring the minimum and maximum level of headings that should be included in the outline. For example, specifying "1" here will result in only the top-level headings being included in the outline. Specifying "2-3" will make the outline include all headings of level 2 and 3, as a nested list. The default is to include all heading levels.
  • The second parameter can be used to specify a custom title (the default is no title).
  • The third parameter selects the style of the outline. This can be either inline or pullout (the latter being the default). The inline style renders the outline as normal part of the content, while pullout causes the outline to be rendered in a box that is by default floated to the right side of the other content.
  • The fourth parameter specifies whether the outline is numbered or not. It can be either numbered or unnumbered (the former being the default). This parameter only has an effect in inline style.

[[PlantUml]]

Aliases: [[plantuml]] [[PlantUML]]

A wiki processor that renders PlantUML diagrams in wiki text.

Example: 

{{{
#!PlantUML
@startuml
Alice -> Bob: Authentication Reque
st
Bob --> Alice: Authentication Response
Alice -> Bob: Another authentication Request
Alice <-- Bob: another authentication Response
@enduml
}}}

Results in:

[[ProjectStats]]

Wiki macro listing some generic Trac statistics.

This macro accepts a comma-separated list of keyed parameters, in the form "key=value". Valid keys:

  • wiki -- statistics for TracWiki, values:
    • count -- show wiki page count
  • prefix -- use with wiki key: only names that start with that prefix are included

'count' is also recognized without prepended key name.

[[RecentChanges]]

List all pages that have recently been modified, ordered by the time they were last modified.

This macro accepts two ordered arguments and a named argument. The named argument can be placed in any position within the argument list.

The first parameter is a prefix string: if provided, only pages with names that start with the prefix are included in the resulting list. If this parameter is omitted, all pages are included in the list.

The second parameter is the maximum number of pages to include in the list.

The group parameter determines how the list is presented:

group=date
The pages are presented in bulleted lists that are grouped by date (default).
group=none
The pages are presented in a single bulleted list.

Tip: if you only want to specify a maximum number of entries and don't want to filter by prefix, specify an empty first parameter, e.g. [[RecentChanges(,10,group=none)]].

[[RepositoryIndex]]

Display the list of available repositories.

Can be given the following named arguments:

format
Select the rendering format:
  • compact produces a comma-separated list of repository prefix names (default)
  • list produces a description list of repository prefix names
  • table produces a table view, similar to the one visible in the Browse View page
glob
Do a glob-style filtering on the repository names (defaults to '*')
order
Order repositories by the given column (one of "name", "date" or "author")
desc
When set to 1, order by descending order

[[SubscriberList]]

Display a list of all installed notification subscribers, including documentation if available.

Optionally, the name of a specific subscriber can be provided as an argument. In that case, only the documentation for that subscriber will be rendered.

Note that this macro will not be able to display the documentation of subscribers if the PythonOptimize option is enabled for mod_python!

[[TicketQuery]]

Wiki macro listing tickets that match certain criteria.

This macro accepts a comma-separated list of keyed parameters, in the form "key=value".

If the key is the name of a field, the value must use the syntax of a filter specifier as defined in TracQuery#QueryLanguage. Note that this is not the same as the simplified URL syntax used for query: links starting with a ? character. Commas (,) can be included in field values by escaping them with a backslash (\).

Groups of field constraints to be OR-ed together can be separated by a literal or argument.

In addition to filters, several other named parameters can be used to control how the results are presented. All of them are optional.

The format parameter determines how the list of tickets is presented:

  • list -- the default presentation is to list the ticket ID next to the summary, with each ticket on a separate line.
  • compact -- the tickets are presented as a comma-separated list of ticket IDs.
  • count -- only the count of matching tickets is displayed
  • rawcount -- only the count of matching tickets is displayed, not even with a link to the corresponding query (since 1.1.1)
  • table -- a view similar to the custom query view (but without the controls)
  • progress -- a view similar to the milestone progress bars

The max parameter can be used to limit the number of tickets shown (defaults to 0, i.e. no maximum).

The order parameter sets the field used for ordering tickets (defaults to id).

The desc parameter indicates whether the order of the tickets should be reversed (defaults to false).

The group parameter sets the field used for grouping tickets (defaults to not being set).

The groupdesc parameter indicates whether the natural display order of the groups should be reversed (defaults to false).

The verbose parameter can be set to a true value in order to get the description for the listed tickets. For table format only. deprecated in favor of the rows parameter

The rows parameter can be used to specify which field(s) should be viewed as a row, e.g. rows=description|summary

The col parameter can be used to specify which fields should be viewed as columns. For table format only.

For compatibility with Trac 0.10, if there's a last positional parameter given to the macro, it will be used to specify the format. Also, using "&" as a field separator still works (except for order) but is deprecated.

[[TitleIndex]]

Insert an alphabetic list of all wiki pages into the output.

Accepts a prefix string as parameter: if provided, only pages with names that start with the prefix are included in the resulting list. If this parameter is omitted, all pages are listed. If the prefix is specified, a second argument of value hideprefix can be given as well, in order to remove that prefix from the output.

The prefix string supports the standard relative-path notation when using the macro in a wiki page. A prefix string starting with ./ will be relative to the current page, and parent pages can be specified using ../.

Several named parameters can be specified:

  • format=compact: The pages are displayed as comma-separated links.
  • format=group: The list of pages will be structured in groups according to common prefix. This format also supports a min=n argument, where n is the minimal number of pages for a group.
  • format=hierarchy: The list of pages will be structured according to the page name path hierarchy. This format also supports a min=n argument, where higher n flatten the display hierarchy
  • depth=n: limit the depth of the pages to list. If set to 0, only toplevel pages will be shown, if set to 1, only immediate children pages will be shown, etc. If not set, or set to -1, all pages in the hierarchy will be shown.
  • include=page1:page*2: include only pages that match an item in the colon-separated list of pages. If the list is empty, or if no include argument is given, include all pages.
  • exclude=page1:page*2: exclude pages that match an item in the colon- separated list of pages.

The include and exclude lists accept shell-style patterns.

[[TracAdminHelp]]

Display help for trac-admin commands.

Examples: 

[[TracAdminHelp]]               # all commands
[[TracAdminHelp(wiki)]]         # all wiki commands
[[TracAdminHelp(wiki export)]]  # the "wiki export" command
[[TracAdminHelp(upgrade)]]      # the upgrade command

[[TracGuideToc]]

Display a table of content for the Trac guide.

This macro shows a quick and dirty way to make a table-of-contents for the Help/Guide. The table of contents will contain the Trac* and WikiFormatting pages, and can't be customized. See the ​TocMacro for a more customizable table of contents.

[[TracIni]]

Produce documentation for the Trac configuration file.

Typically, this will be used in the TracIni page. The macro accepts two ordered arguments and two named arguments.

The ordered arguments are a configuration section filter, and a configuration option name filter: only the configuration options whose section and name start with the filters are output.

The named arguments can be specified:

section
a glob-style filtering on the section names
option
a glob-style filtering on the option names

[[UserQuery]]

Wiki macro listing users that match certain criteria.

This macro accepts a comma-separated list of keyed parameters, in the form "key=value". Valid keys:

  • perm -- show only that users, a permission action given by value has been granted to
  • locked -- retrieve users, who's account has/has not been locked depending on boolean value
  • format -- output style: 'count', 'list' or comma-separated values (default)
  • nomatch -- replacement wiki markup that is displayed, if there's no match and output style isn't 'count' either

'count' is also recognized without prepended key name. Other non-keyed parameters are:

  • locked -- alias for 'locked=True'
  • visit -- show a list of accounts with last-login information, only available in table format
  • name -- forces replacement of maching username with their corresponding full names, if available; adds a full names column if combined with 'visit'
  • email -- append email address to usernames, if available

Requires USER_VIEW permission for output in any format other then 'count'. A misc placeholder with this statement is presented to unprivileged users.

[[Workflow]]

Render a workflow graph.

This macro accepts a TracWorkflow configuration and renders the states and transitions as a directed graph. If no parameters are given, the current ticket workflow is rendered.

In WikiProcessor mode the width and height arguments can be specified (Defaults: width = 800 and height = 600).

The repository-scoped path of a workflow file can be specified as either a macro or WikiProcessor file argument. The file revision can be specified by appending @<rev> to the path. The file argument value must be enclosed in single or double quotes. (Since 1.3.2).

Examples: 

[[Workflow()]]

[[Workflow(go = here -> there; return = there -> here)]]

[[Workflow(file=/contrib/workflow/enterprise-workflow.ini@1)]]

{{{#!Workflow file="/contrib/workflow/enterprise-workflow.ini"
}}}

{{{#!Workflow width=700 height=700
leave = * -> *
leave.operations = leave_status
leave.default = 1

create = <none> -> new
create.default = 1

create_and_assign = <none> -> assigned
create_and_assign.label = assign
create_and_assign.permissions = TICKET_MODIFY
create_and_assign.operations = may_set_owner

accept = new,assigned,accepted,reopened -> accepted
accept.permissions = TICKET_MODIFY
accept.operations = set_owner_to_self

resolve = new,assigned,accepted,reopened -> closed
resolve.permissions = TICKET_MODIFY
resolve.operations = set_resolution

reassign = new,assigned,accepted,reopened -> assigned
reassign.permissions = TICKET_MODIFY
reassign.operations = set_owner

reopen = closed -> reopened
reopen.permissions = TICKET_CREATE
reopen.operations = del_resolution
}}}

Macros from around the world

The ​Trac Hacks site provides a wide collection of macros and other Trac plugins contributed by the Trac community. If you are looking for new macros, or have written one that you would like to share with the world, don't hesitate to visit that site.

Developing Custom Macros

Macros, like Trac itself, are written in the ​Python programming language and are developed as part of TracPlugins.

For more information about developing macros, see the ​development resources on the main project site.

Here are 2 simple examples showing how to create a Macro. Also, have a look at ​Timestamp.py for an example that shows the difference between old style and new style macros and at the ​macros/README which provides a little more insight about the transition.

Macro without arguments

To test the following code, you should saved it in a timestamp_sample.py file located in the TracEnvironment's plugins/ directory. 

from datetime import datetime
# Note: since Trac 0.11, datetime objects are used internally

from genshi.builder import tag

from trac.util.datefmt import format_datetime, utc
from trac.wiki.macros import WikiMacroBase

class TimeStampMacro(WikiMacroBase):
    """Inserts the current time (in seconds) into the wiki page."""

    revision = "$Rev$"
    url = "$URL$"

    def expand_macro(self, formatter, name, text):
        t = datetime.now(utc)
        return tag.strong(format_datetime(t, '%c'))

Macro with arguments

To test the following code, you should save it in a helloworld_sample.py file located in the TracEnvironment's plugins/ directory. 

from genshi.core import Markup

from trac.wiki.macros import WikiMacroBase

class HelloWorldMacro(WikiMacroBase):
    """Simple HelloWorld macro.

    Note that the name of the class is meaningful:
     - it must end with "Macro"
     - what comes before "Macro" ends up being the macro name

    The documentation of the class (i.e. what you're reading)
    will become the documentation of the macro, as shown by
    the !MacroList macro (usually used in the WikiMacros page).
    """

    revision = "$Rev$"
    url = "$URL$"

    def expand_macro(self, formatter, name, text, args):
        """Return some output that will be displayed in the Wiki content.

        `name` is the actual name of the macro (no surprise, here it'll be
        `'HelloWorld'`),
        `text` is the text enclosed in parenthesis at the call of the macro.
          Note that if there are ''no'' parenthesis (like in, e.g.
          [[HelloWorld]]), then `text` is `None`.
        `args` are the arguments passed when HelloWorld is called using a
        `#!HelloWorld` code block.
        """
        return 'Hello World, text = %s, args = %s' % \
            (Markup.escape(text), Markup.escape(repr(args)))

Note that expand_macro optionally takes a 4th parameter args. When the macro is called as a WikiProcessor, it's also possible to pass key=value 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).

For example, when writing: 

{{{#!HelloWorld style="polite" -silent verbose
<Hello World!>
}}}

{{{#!HelloWorld
<Hello World!>
}}}

[[HelloWorld(<Hello World!>)]]

One should get: 

Hello World, text = <Hello World!> , args = {'style': u'polite', 'silent': False, 'verbose': True}
Hello World, text = <Hello World!> , args = {}
Hello World, text = <Hello World!> , args = None

Note 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).

You can also recursively use a wiki Formatter (from trac.wiki import Formatter) to process the text as wiki markup: 

from genshi.core import Markup
from trac.wiki.macros import WikiMacroBase
from trac.wiki import Formatter
import StringIO

class HelloWorldMacro(WikiMacroBase):
    def expand_macro(self, formatter, name, text, args):
        text = "whatever '''wiki''' markup you want, even containing other macros"
        # Convert Wiki markup to HTML, new style
        out = StringIO.StringIO()
        Formatter(self.env, formatter.context).format(text, out)
        return Markup(out.getvalue())
Note: See TracWiki for help on using the wiki.