created: 20220917112233317 modified: 20221019081352266 tags: Pragmas title: Pragma: \define type: text/vnd.tiddlywiki The ''\define'' [[pragma|Pragmas]] is used to [[define macros|Macro Definitions]]. It is a shortcut syntax for the SetVariableWidget. The usual form allows macros to span multiple lines. ``` \define ([:],[:]...) \end [] ``` Note that the `\end` marker can optionally specify the name of the macro to which it relates which allows macro definitions to be nested. There is also a single line form for shorter macros: ``` \define ([:],[:]...) ``` The first line of the definition specifies the macro name and any parameters. Each parameter has a name and, optionally, a default value that is used if no value is supplied on a particular call to the macro. The lines that follow contain the text of the macro text (i.e. the snippet represented by the macro name), until `\end` appears on a line by itself: <$codeblock code={{$:/editions/tw5.com/macro-examples/say-hi}}/> Alternatively, the entire definition can be presented on a single line without an `\end` marker: ``` \define sayhi(name:"Bugs Bunny") Hi, I'm $name$. ``` Macro definitions can be nested by specifying the name of the macro in the `\end` marker. For example: < \end actions <$button actions=<>> $caption$ \end special-button <> """>> A more formal [[presentation|Macro Definition Syntax]] of this syntax is also available.