View source for every/en

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{{DISPLAYTITLE:every}} 
[[Type signature|Type]]: <syntaxhighlight lang="haskell" inline>every :: Pattern Int -> (Pattern a -> Pattern a) -> Pattern a -> Pattern a</syntaxhighlight>

'''every''' is function, that allows you to apply another function conditionally. It takes three inputs, how often the function should be applied (e.g. <syntaxhighlight lang="haskell" inline>3</syntaxhighlight> to apply it every 3 cycles), the function to be applied, and the pattern you are applying it to. 

For example to reverse a pattern every three cycles (and for the other two play it normally):

<syntaxhighlight lang="haskell">
d1 $ every 3 rev $ n "0 1 [~ 2] 3" # sound "arpy"
</syntaxhighlight>

Note that if the function you're applying requires additional parameters itself (such as <syntaxhighlight lang="haskell" inline>fast 2</syntaxhighlight> to make a pattern twice as fast), then you'll need to wrap it in parenthesis, like so:

<syntaxhighlight lang="haskell">
d1 $ every 3 (fast 2) $ n "0 1 [~ 2] 3" # sound "arpy"
</syntaxhighlight>

Otherwise, the <syntaxhighlight lang="haskell" inline>every</syntaxhighlight> function will think it is being passed too many parameters.

See also [[every']].

[[Category:Functions]] [[Category:Higher-order functions]] [[Category:Conditional Transformers]]