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Tacit programming: Difference between revisions
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== Trains == | == Trains == | ||
A train is a series of functions in isolation. An isolated function is either surrounded by parentheses or named. | A train is a series of functions in isolation. An isolated function is either surrounded by parentheses or named. Below, <source lang=apl inline>⍺</source> and <source lang=apl inline>⍵</source> refer to the arguments of the train. <source lang=apl inline>f</source>, <source lang=apl inline>g</source>, and <source lang=apl inline>h</source> are function (which themselves can be tacit or not), and <source lang=apl inline>A</source> is an array. The arguments are processed by the following rules: | ||
A 2-train is an ''atop'': | A 2-train is an ''atop'': | ||
<source lang=apl> | {| | ||
|<source lang=apl> (g h) ⍵</source>|| {{←→}} ||<source lang=apl>g ( h ⍵)</source> | |||
⍺ (g h) ⍵ | |- | ||
</source> | |<source lang=apl>⍺ (g h) ⍵</source>|| {{←→}} ||<source lang=apl>g (⍺ h ⍵)</source> | ||
|} | |||
A 3-train is a ''fork'': | A 3-train is a ''fork'': | ||
<source lang=apl> | {| | ||
|<source lang=apl> (f g h) ⍵</source>|| {{←→}} ||<source lang=apl>( f ⍵) g ( h ⍵)</source> | |||
⍺ (f g h) ⍵ | |- | ||
</source> | |<source lang=apl>⍺ (f g h) ⍵</source>|| {{←→}} ||<source lang=apl>(⍺ f ⍵) g (⍺ h ⍵)</source> | ||
|} | |||
The ''left tine'' of a fork can be an array: | |||
{| | |||
|<source lang=apl> (A g h)</source>|| {{←→}} ||<source lang=apl>A g ( h ⍵)</source> | |||
|- | |||
|<source lang=apl>⍺ (A g h) ⍵</source>|| {{←→}} ||<source lang=apl>A g (⍺ h ⍵)</source> | |||
|} | |||
Only [[dzaima/APL]] allows <source lang=apl inline>(A h)</source>, which it treats as <source lang=apl inline>A∘h</source>.<ref>dzaima/APL: [https://github.com/dzaima/APL/blob/ceea05e25687988ed0980a4abf4b9249b736543f/docs/differences.txt#L19 Differences from Dyalog APL]. Retrieved 09 Jan 2020.</ref> | Only [[dzaima/APL]] allows <source lang=apl inline>(A h)</source>, which it treats as <source lang=apl inline>A∘h</source>.<ref>dzaima/APL: [https://github.com/dzaima/APL/blob/ceea05e25687988ed0980a4abf4b9249b736543f/docs/differences.txt#L19 Differences from Dyalog APL]. Retrieved 09 Jan 2020.</ref> | ||