caption: Macro Definitions
created: 20150220181617000
modified: 20220918115917656
tags: WikiText Macros
title: Macro Definitions
type: text/vnd.tiddlywiki

!! Introduction

This tiddler describes the different ways in which [[macros|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
```

!! Macro Definition with Set Widget

Macros are implemented as a special type of [[variable|Variables]] and so internally are actually defined with a <<.wlink SetWidget>> widget.

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

<<.note """that it is not currently possible to specify parameters when defining a macro with the  <<.wlink SetWidget>> widget.""">>

!! Importing Macro Definitions

The [[Pragma: \import]] or <<.wlink ImportVariablesWidget>> widget can be used to copy macro definitions from another tiddler.

!! Global Macro Definitions

Macros can be made available globally by placing them in a tiddler titled with the name of the global prefixed with `$:/global/`. See [[Global Definitions]] for details.

!! `$:/tags/Macro` Tag

For backwards compatibility, global macros can also be defined using the [[SystemTag: $:/tags/Macro]]. The new [[Global Definitions]] mechanism is [[preferred|Macro Pitfalls]] for new applications.

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 <<.js-macro-link "written as JavaScript modules">>.