Higher Order Function Question

Alex Peake <>
Fri May 24 05:56:02 CEST 2002


Can someone help me with this (no doubt simple) problem.

I try:

1> attr:isPk(Attr).
false

2> not attr:isPk(Attr).
true

3> not(attr:isPk(Attr)).
true

but cannot find a permutation/combination of:

4> apply({attr, isPk}, [A1]).
false

that can include "not" and work.

Actually, I am trying to lists:filter( ...not isPk... SomeList).

The simple is to define notIsPk(Attr), or perhaps lists:filter( fun(Attr) ->
.. end  but they are not an abstraction of "complement".

Perhaps I should define a function complement(Fn) that returns a function
that is the complement of the function passed?

Perhaps there is already an Erlang way to do this (I hope).

Alex





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