Difference between revisions of "Dfn"

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== External links ==
 
== External links ==
 
* [[Wikipedia: Direct function]]
 
* [[Wikipedia: Direct function]]
* [[Dyalog Ltd.]]'s [https://dfns.dyalog.com dfns website] (created and maintained by John Scholes until his passing)
+
* [[Dyalog Ltd.]]'s [https://dfns.dyalog.com dfns website] (created and, until his passing, maintained by John Scholes)
 
{{APL syntax}}
 
{{APL syntax}}

Revision as of 12:28, 20 December 2019

A dfn (pronounced "dee fun") is an alternative way to define a function and operator, invented by John Scholes. A dfn operator can also be called a dop (pronounced "dee op").

As of 2020, dfns are fully implemented in Dyalog APL, NARS2000, ngn/apl, dzaima/APL, and partially in GNU APL.

Wikipedia has a full treatment of dfns.

Documentation

External links

APL syntax [edit]
General Comparison with traditional mathematicsPrecedenceTacit programming
Array Numeric literalStringStrand notationObject literalArray notation
Function ArgumentFunction valenceDerived functionDerived operatorNiladic functionMonadic functionDyadic functionAmbivalent functionDefined function (traditional)DfnFunction train
Operator OperandOperator valenceTradopDopDerived operator
Assignment MultipleIndexedSelectiveModified
Other Function axisBranchQuad nameSystem commandUser commandKeywordDot notationFunction-operator overloading