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Overloading the operator in functional amend

How to overload an operator in functional amend?

s:string (`a1`b2`c3)
b:string til 2

using functional amend with , gives 

q)@[s;0 2;,;b]
("a10";"b2";"c31")

I want to overload the , (append) to prefix the content of list b to list a like : 

("0a1";"b2";"1c3")
Solution

  • You need to use a custom function {y,x} instead if , to achieve this 

    @[s;0 2;{y,x};b]
("0a1";"b2";"1c3")

    Please note that here , is a dyadic function; Any other dyadic function e.g. {y,x} can be used in functional amend with valance 4.

    The general format of functional amend is following, where f is dyadic function 

     @[L;I;f;y]

q)@[1 2 3 4 ;1 3;*;5 ]   // * is dyadic function {x*y} 
1j, 10j, 3j, 20j

    and when f is monadic function

     @[L;I;f]

q)@[1 2 3 4 ;1 3;neg ]
1j, -2j, 3j, -4j