[Haskell-cafe] A really bad way to say "all isSpace"

[Isaac Dupree]

Neil Mitchell wrote:
> Hi,
> 
> Reading through the code to read:
> 
> read s          =  case [x | (x,t) <- reads s, ("","") <- lex t] of
>            [x] -> x
>            []  -> error "Prelude.read: no parse"
>            _   -> error "Prelude.read: ambiguous parse"
> 
> Reading through the code to lex, it appear that it will return
> [("","")] if and only if all isSpace t.
> 
> If this is really the case, does it make sense to state all isSpace t?
> It has a much clearer meaning to me.

I think 'lex' is supposed to not understand (haskell-style) comments - 
which I agree with - so I agree that it would be "better" to say (all 
isSpace t).  I might even have thought that in passing when reading that 
code, I don't remember....

Isaac