Hi Andrew, I haven't read your whole message but if shortness is your goal, here are some ideas: Andrew Savige wrote:
rtoa c = 10^(205558`mod`(ord c)`mod`7)`mod`9995
I'm not suggesting that magic formulae are useful outside of golf and this second rtoa function, though shorter, is much less clear. I might add that this particular magic formula appears to be less useful in Haskell golf than the other languages because `mod` is five times longer than the % operator of the other languages. :)
Why not rename mod like so? (%)=mod rtoa c=10^(205558%ord c%7)%9995
Alternatively, you could write the rtoa function using an approach taken from the original HaskellWiki solution:
rtoa = fromJust . flip lookup (zip "IVXLCDM" [1,5,10,50,100,500,1000])
You can write this as: Just rtoa=flip lookup (zip "IVXLCDM" [1,5,10,50,100,500,1000]) Which is another few characters shorter. :-) HTH, Martijn.