[Haskell-cafe] Re: Proving my point

[Philippa Cowderoy]

On Fri, 16 May 2008, Achim Schneider wrote:

> Philippa Cowderoy <flippa at flippac.org> wrote:
> 
> > On Fri, 16 May 2008, Achim Schneider wrote:
> > 
> > Guess who ran into that with a separate token for
> > layout-inserted braces?
> > 
> It can't be me, as I attempted to be as lazy as possible, not going for
> a tokenising pass, and ended up being too lazy.
> 

Nah, you just picked the wrong way to attempt discipline. I don't use 
separate tokenising/lexing passes in a lot of my code (though you can't 
really avoid it when you want to do layout), it's a matter of knowing how 
it's done. Unless you've got a lexical structure that prevents it (which 
is to say, there're situations in which two tokens following each other 
aren't allowed to have whitespace between them), it's a good idea to have 
your token productions eat any whitespace following them, and then your 
toplevel becomes:

do {whitespace; r <- realTopLevel; eof; return r}

and then you need never worry about it again.

-- 
flippa at flippac.org

Ivanova is always right.
I will listen to Ivanova.
I will not ignore Ivanova's recomendations.
Ivanova is God.
And, if this ever happens again, Ivanova will personally rip your lungs out!