Introduction

This tiddler describes the different ways in which macros can be defined.

Macro Definition Pragma

Macros are created using the Pragma: \define at the start of a tiddler. The definitions are available in the rest of the tiddler that defines them, plus any tiddlers that it transcludes.

\define mymacro(param)
This is the macro text (param=$param$)
\end

Nested Macro Definitions

Macro definitions can be nested to any number of required levels by specifying the name of the macro in the \end marker. Nested macro definitions must appear at the start of the definition that contains them. For example:

\define special-button(caption:"Click me")
\define actions()
<$action-sendmessage $message="tm-notify" $param="HelloThere"/>
\end actions
<$button actions=<<actions>>>
$caption$
</$button>
\end special-button

<<special-button>>

Note that the textual substitution of macro parameters that occurs when the outer macro is rendered will apply to the nested definitions as well. That generally means that textual substitution of macro parameters should not be used within nested macros.

Parameters of nested macros can also be accessed via the <<__variablename__>> syntax. As ordinary variables, these parameters are available within nested child macros (and grandchildren etc).

Macro Definition with Set Widget

Macros are implemented as a special type of variable and so internally are actually defined with a $set widget.

<$set name="mymacro" value="This is the macro text">
...
</$set>

Importing Macro Definitions

The Pragma: \import or $importvariables widget can be used to copy macro definitions from another tiddler.

$:/tags/Macro Tag

Global macros can be defined using the SystemTag: $:/tags/Macro.

The tag SystemTag: $:/tags/Macro/View is used to define macros that should only be available within the main view template and the preview panel.

The tag SystemTag: $:/tags/Macro/View/Body is used to define macros that should only be available within the main view template body and the preview panel.

JavaScript Macros

Macros can also be written as JavaScript modules.