[Haskell-cafe] Comments and suggestions on code

[Jonathan Cast]

On 11 Jan 2008, at 2:24 PM, Andre Nathan wrote:

> processEntry :: DirStream -> IO ()
> processEntry ds = do
>   entry <- readDirStream ds
>   if entry =~ "^[0-9]+$"
>     then do
>       putStrLn entry
>       processEntry ds
>     else
>       if entry == "" then return () else processEntry ds
>
> bar :: IO ()
> bar = do
>   ds <- openDirStream "."
>   processEntry ds
>   closeDirStream ds

This is a 200% increase in code size for a 75% decrease in execution  
time.  (And, in general, the complexity can be much higher).  That's  
an engineering tradeoff, and one you'll have to decide yourself;  
there's not much that can be done to make it go away.

jcc