Re: Ada Popularity: Comparison of Ada/Charles with C++ STL (and Perl)

[anders@use.reply.to (Anders Gidenstam)]

In article <u6564dfge.fsf@obry.org>,
	Pascal Obry <pascal@obry.org> writes:
> 
> andreatta@mail.chem.sc.edu (Dan Andreatta) writes:
> 
>> And I write it in Haskell. 14 lines. OK, I cheated, I used GHC libraries.
> 
> And it is just unreadable ! I just can't understand how this is supposed
> to work!

It is not all that horrible once you realize that $ is function
application, for example

  putStr $ show $ take 10 $ count_words (map (map toLower) $ words f)

can also be written

  putStr (show (take 10 (count_words (map (map toLower) (words f)))))

Still, I'm not sure Dan's version behaves as expected since it sometimes
treats non-alphabetic characters as words.

Here is another Haskell version and this time in pure Haskell 98 at the
expense of one more line. Enjoy! 

module Main where

import System
import List
import Char

count_words :: [String] -> [(Int, String)]
count_words xs = sortBy comp $ init $ foldr count_same [(0, "")] $ sort xs
  where count_same w1 (y1@(c, w2):ys) = if (w1 == w2)
					then (c + 1, w1):ys else (1,w1):y1:ys 
        comp (c1, _) (c2, _) = compare c2 c1

main = do args <- getArgs
	  f <- readFile (args!!0)
          putStr $ concat $ map prettyShow $ take 10 $ count_words $ wordify f
       where wordify xs       = words $ map toLower $ map onlyAlpha xs
	     onlyAlpha x      = if isAlpha x then x else ' '
	     prettyShow (c,w) = w ++ " " ++ show c ++ "\n"


Well, I think it is nifty even if you don't :)

/Anders
-- 
"Luck is my middle name," said Rincewind, indistinctly. "Mind you,
 my first name is Bad." 
   -- (Terry Pratchett, Interesting Times)