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[REBOL] Re: Maplist?

From: larry:ecotope at: 8-Sep-2001 15:23

Hi David, Here is a short and simple version of MAP. I agree it would be nice if RT would implement a fast internal version of MAP. I find it extremely useful. map: func [f1 b /local out][ out: copy [] repeat el b [append/only out f1 :el] out ] Use it like this for a named function (note the : prefix is needed to delay full evaluation).
>> map :to-integer ["123" "45667"]
== [123 45667] If the named function needs a refinement switch you delay evaluation with a leading ' , like this:
>> map 'sine/radians [0 30 90]
== [0 -0.988031624092862 0.893996663600556] You can also use it with an anonymous function (defined on the fly) like this:
>> map func [x][x * x] [1 2 3]
== [1 4 9] I am very interested in the list operators of Scheme, Lisp, and modern functional languages like Haskell, Miranda, and Clean. I have implemented many of them in REBOL. So feel free to ask more on this topic. You might also benefit from Ladislav Mecir's highfun.r library: Cheers -Larry