created: 20181031175129475
modified: 20211030223407188
tags: [[subfilter Operator]] [[Operator Examples]]
title: subfilter Operator (Examples)
type: text/vnd.tiddlywiki

\define recent-mods() [has[modified]!sort[modified]limit[5]]
\define display-variable(name)
''<$text text=<<__name__>>/>'': <code><$text text={{{ [<__name__>getvariable[]] }}}/></code>
\end

Literal filter operands can be used, but such cases are better rewritten without using <<.op subfilter>>:
<<.operator-example 1 "[subfilter[one two three]addsuffix[!]]" "same as `one two three +[addsuffix[!]]`">>

The <<.op subfilter>> operator can be used to dynamically define parts of a [[filter run|Filter Run]]. This is useful for sharing a common pieces of a filter across multiple filters.

For example, this variable:

* <<display-variable recent-mods>>

can be used in one filter like this:

<<.operator-example 2 "[tag[Filter Operators]subfilter<recent-mods>addsuffix[!]]" "same as `[tag[Filter Operators]has[modified]!sort[modified]limit[5]addsuffix[!]]`">>

and in another similar filter like this:
<<.operator-example 3 "[tag[ActionWidgets]subfilter<recent-mods>addprefix[!]]">>

Variables are not the only way to define dynamic subfilters. [[Text references|TextReference]] can be used to load a subfilter from a tiddler field (see also [[Filter Parameter]]):
<<.operator-example 4 "[subfilter{$:/StoryList!!list}limit[5]]">>
<<.operator-example 5 "[subfilter{$:/StoryList!!list}subfilter<recent-mods>]">>