Function array

A function array, or fnarray, is a value that is conceptually an array of functions. It can be applied to arguments, which applies each function independently and gives an array of results. Several languages that don't ordinarily support placing a function in an array have function arrays as a special construct: Dyalog APL, dzaima/APL, and Nial, which uses the name "atlas".

In dzaima/APL and Nial function arrays are constructed by the vector form of array notation, allowing only rank-1 function arrays. In Dyalog APL they can be produced by taking a field of an array of namespaces that all contain that field with a function value. fnarray in the dfns workspace wraps this functionality in an operator.^[1]

The FP language features a "function composition" construction that applies like a function array. In the I language, which has first-class functions, lists may be applied to arguments, and apply each element independently, so that a list of functions also behaves like a function array.

References

↑ Dfns workspace. fnarray ― Array of functions.

APL syntax [edit]
General	Comparison with traditional mathematics ∙ Precedence ∙ Tacit programming (Train, Hook, Split composition)
Array	Numeric literal ∙ String ∙ Strand notation ∙ Object literal ∙ Array notation (design considerations)
Function	Argument ∙ Function valence ∙ Derived function ∙ Derived operator ∙ Niladic function ∙ Monadic function ∙ Dyadic function ∙ Ambivalent function ∙ Defined function (traditional) ∙ Dfn ∙ Function train
Operator	Operand ∙ Operator valence ∙ Tradop ∙ Dop ∙ Derived operator
Assignment	Multiple ∙ Indexed ∙ Selective ∙ Modified
Other	Function axis ∙ Bracket indexing ∙ Branch ∙ Statement separator ∙ Quad name ∙ System command ∙ User command ∙ Keyword ∙ Dot notation ∙ Function-operator overloading ∙ Control structure ∙ Comment

[1] Dfns workspace. fnarray ― Array of functions.

[1]

Function array

References

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