[Haskell-cafe] module Crypt_Discordian - code critique requested

[Arthur van Leeuwen]

On Wed, Feb 23, 2005 at 12:27:19AM +0000, Terrence Brannon wrote:
> 
> Hi, I am getting into Haskell so I decided to convert a Perl module of
> mine:
> 
>         http://cpan.uwinnipeg.ca/htdocs/Crypt-Discordian/Crypt/Discordian.html
> 
> into Haskell. I was pleased at the cleanliness and conciseness of the
> Haskell code. However, I am sure that it can be improved on and am
> soliciting any feedback you may have about this module.
> 
> Thanks,
> metaperl on #haskell
> 
> module Crypt_Discordian 
>     where
> 
> import List
> 
> vowel_list = "aeiouAEIOU"
> 
> is_vowel c = c `elem` vowel_list
> 
> move_vowels lis = move_vowels' lis [] []
> 
> move_vowels' []     c v = v ++ c
> move_vowels' (x:xs) c v
>     | is_vowel x  = move_vowels' xs    c  (x:v)
>     | otherwise   = move_vowels' xs (x:c)    v
> 
> remove_spaces str = filter (\x -> x /= ' ') str
> 
> encrypt str = List.sort $ move_vowels $ remove_spaces str

How about

> module CryptDiscordian
> where
>
> import List
>
> vowels = "aeiouAEIOU"
> isVowel = (flip elem) vowel_list
>
> moveVowels xs = filter (not . isSpace) $ 
>                     (filter (not . isVowel) xs ++ filter (is_vowel) xs)
>
> encryptDiscordian xs = map chr $ sort $ map (ord . toLower) $ 
>                             reverse $ moveVowels xs

[snip description of algorithm]

Obviously, if it is implemented differently it won't be the Discordian
encryption anymore, now will it? Note that my version is more conforming
than yours, as you don't convert to numbers and back...

Unfortunately, the algorithm doesn't state how to deal with capitalization,
so I chose to just map to lowercase...

Doei, Arthur.

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