Function axis: Difference between revisions

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462 bytes added ,  08:59, 4 November 2019
Remove name "Bracket Axis" and explain derived functions with axis
Miraheze>Marshall
m (Marshall moved page Bracket axis to Function axis over redirect: Eh, axis applies to the derived function (even if it was initially attached to an operator). We should name things after the functionality and not the syntax unless there is a really strong reason to do so.)
Miraheze>Marshall
(Remove name "Bracket Axis" and explain derived functions with axis)
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{{Built-in|Bracket axis|[ax]}} or '''function axis''' is the a special syntax whereby many APLs allow the behavior of a function to be modified, for example <source lang=apl inline>⌽[2]</source> to [[Rotate]] along the second [[axis]]. Axis specification was a feature of [[Iverson notation]] and was ubiquitous in early APLs; many newer APLs which adhere to [[leading axis theory]] reject the use of axis specification in favor of the [[Rank operator]] because it is a fully general operator while the behavior of functions with axis must be defined for each function separately.
{{Built-in|Function axis|[ax]}} is a special syntax which modifies the behavior of a function, for example <source lang=apl inline>⌽[2]</source> to [[Rotate]] along the second [[axis]]. Axis specification was a feature of [[Iverson notation]] and was ubiquitous in early APLs; many newer APLs which adhere to [[leading axis theory]] reject the use of axis specification in favor of the [[Rank operator]] because it is a fully general operator while the behavior of functions with axis must be defined for each function separately.


== Functions ==
== Functions ==
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* [[Scan]] works on the specified right argument axis.
* [[Scan]] works on the specified right argument axis.


In [[Dyalog APL]], a slash with axis retains its [[function-operator overloading]]: it can be applied as an operator or as a dyadic function ([[Replicate]] or [[Expand]]).
In [[SHARP APL]], [[Replicate]] and [[Expand]] are also included in this category as they are operators and not functions.
 
Axis specification always modifies the [[derived function]] obtained from an operator, and not the operator itself. The exact syntax may vary: in most cases a set of brackets is parsed like a monadic operator and applies directly to the derived function; sometimes brackets can be applied directly to an operator, in which case the derived function produced by this operator is modified. In [[Dyalog APL]], a slash with axis retains its [[function-operator overloading]]: it can be applied as an operator or as a dyadic function ([[Replicate]] or [[Expand]]).


== External links ==
== External links ==
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