[Haskell-beginners] Function nesting
Joe Van Dyk
joe at fixieconsulting.com
Thu Jan 21 21:28:52 EST 2010
On Thu, Jan 21, 2010 at 6:55 AM, Daniel Fischer
<daniel.is.fischer at web.de> wrote:
> Am Donnerstag 21 Januar 2010 15:02:11 schrieb Zbigniew Stanasiuk:
>> Hi all,
>>
>> I've just started learning Haskell and I have no idea how to nest
>> function in following structure:
>> Mod(5*Mod(4*Mod(3*Mod(2*Mod(1, m), m), m), m), m) ... etc.
>> Could someone help me.
>
> Instead of func(a,b), write func a b. Arguments which are compund
> expressions themselves must be parenthesized, so
>
> mod (5*mod (4*mod (3*mod (2*mod 1 m) m) m) m) m
>
> But that is completely unreadable.
>
> foldl' (\z x -> (x*z) `mod` m) 1 [1 .. 5]
To the untrained eye, the first version contains a lot less weird
syntax. You only have to know what mod does, and how parenthesis
work, both of which you learn in the third grade or so.
--
Joe Van Dyk
http://fixieconsulting.com
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