[Haskell-beginners] A first try

[Panagiotis Koutsourakis]

Thank you very much Jared. Much appreciated.

On Fri, Jun 24, 2011 at 4:51 PM, Jared Hance <jaredhance at gmail.com> wrote:
> Okay, I'm going to give some more stylistic notes.
>
>> 8. let combined = parseArgs Args
>
> You don't need this one.
>
>> Lines 9 - 11
>> let sep = separateFiles args
>>      fl = head (fst sep)
>> showResultsFile fl (snd sep)
>
> Why not:
>
> let (f, s) = separateFiles args
> showResultsFile (head f) s
>
>> Lines 19-20
>> processFile fl flags =
>>   mapM dispatch [(flag, fl) | flag <- flags]
>
> Why isn't this on one line? Its not particularly long.
>
>> Lines 25-31
>> dispatch (fl, fn) = do
>>   handle <- openFile fl ReadMode
>>   contents <- hGetContents handle
>>   let cnt = getCounter fn
>>       res = cnt contents
>>   hClose handle
>>   return res
>
> Cleaner is:
>
> dispatch (fl, fn) = do contents <- withFile fl ReadMode hGetContents
>                       return $ getCounter fn contents
>
> However also note that you are defining a function of the form
>
> f :: (a, b) -> c
>
> rather than the better
>
> f :: a -> b -> c
>
> Naturally, I see that the reason is that you are calling it from mapM.
> However, I would define dispatch as a curried function, and then use
> `curry dispatch` in your mapM. It makes dispatch much cleaner.
>
>> Lines 36-44
>> a bunch of putStrLn
>
> You could also use mapM_ putStrLn [list of string to put out], removing
> duplicate uses of putStrLn here.
>
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-- 
Panagiotis Koutsourakis