10 lines
882 B
Plaintext
10 lines
882 B
Plaintext
created: 20230726143929233
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modified: 20230726150604831
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tags: [[Variable Usage]]
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title: Behaviour of variables invoked via filter expression function call
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type: text/vnd.tiddlywiki
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|tc-first-col-min-width|k
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|!how declared|!behaviour|
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|\define, <<.wlink SetWidget>>, <<.wlink LetWidget>>, <<.wlink VarsWidget>>, \procedure, \widget|Every function is a variable, but only variables defined using \function are invokable using the <<.olink function>> filter operator. Attempts to use a non-function variable is the same as if the function doesn't exist. The behavior in this case is like the identity function. All filter input is passed unchanged to the output.|
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|\function|The body text of the function is treated as a filter expression and evaluated. This filter expression can itself contain a function call. Filter expressions can be factored out into functions arbitrarily deep.| |