[Haskell-cafe] Re: Functors [Comments from OCaml Hacker Brian Hurt]

[Heinrich Apfelmus]

Andrew Coppin wrote:
> Heinrich Apfelmus wrote:
>> Andrew Coppin wrote:
>>  
>>>> instance (Monad m) => Functor m where
>>>>   fmap f ma = do a <- ma; return (f a)
>>>>         
>>> While that's quite interesting from a mathematical point of view, how is
>>> this "useful" for programming purposes?
>>>     
>>
>> Surely, you agree that  liftM  is "useful"? Because that's the same
>> thing.
>>   
> 
> Then why not just use liftM? (That way, you know what it does...)

   liftM (*1) [1..10]

 = [2,4,6,8,10,12,14,16,18,20]


Regards,
apfelmus

-- 
http://apfelmus.nfshost.com