Built Map, Reduce, & Filter

[Liam Goodacre]

Hey, I just found this and I'm having lots of fun with it!

I've built 'map', 'reduce', and 'filter' functions.

What do you think?

http://www.lastcalc.com/meQVUB5

I've added 'add', 'add10', 'mul', 'sub', and 'myfn' for testing they work.

Cheers,

Liam.

[Liam Goodacre]

These are my function definitions:

map(Fn) = map(Fn)

map(Fn)([]) = []

map(Fn)([H...T]) = [Fn(H)...map(Fn)(T)]

reduce(Fn) = reduce(Fn)

reduce(Fn)([H...T]) = reduce(Fn)(H)(T)

reduce(Fn)(V)([]) = V

reduce(Fn)(V)([H...T]) = reduce(Fn)(Fn(V)(H))(T)

filter(Fn) = filter(Fn)

filter(Fn)([]) = []

filter(Fn)([H...T]) = if Fn(H) then [H...filter(Fn)(T)] else filter(Fn)(T)

[Ian Clarke]

Liam,

I'm very excited that you're having fun :-)

Actually, I didn't anticipate doing function application in the way that you are doing it, although it makes perfect sense.  I guess that it is a good sign when people start doing things in ways I didn't anticipate :-)

On my to-do list is an explicit syntax for applying a pre-defined function, perhaps "apply X to BLAH".

Ultimately I want to add "native" support for a lot of these functional programming constructs, since they will be a lot faster than the user-defined versions.

Thanks for you interest, please keep playing around and let me know if you have any suggestions about how to make things better :-)

Ian.

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Ian Clarke

Blog: http://blog.locut.us/