I noticed that StateT can enclose IO actions for instance. So you are saying the whole Parsec library would need to be rewritten as something like a ParsecT transformer monad for this to work? If this is the case I suppose I will stick with returning my list of include files. - Greg ----- Original Message ---- From: Bulat Ziganshin To: Gregory Propf Cc: haskell-cafe@haskell.org Sent: Saturday, August 11, 2007 11:33:00 PM Subject: Re: Fw: [Haskell-cafe] IO within parser Hello Gregory, Sunday, August 12, 2007, 9:32:04 AM, you wrote:

...

I've been struggling with writing a parser that needs to parse include files within source files.

Parsec can't accomplish with without using unsafePerformIO because it's monad is pure. it's algorithmically impossible to have any i/o actions inside it. there was plans to rewrite Parsec in monad-transformer way and afair it was even one of GSOC projects -- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com ____________________________________________________________________________________ Fussy? Opinionated? Impossible to please? Perfect. Join Yahoo!'s user panel and lay it on us. http://surveylink.yahoo.com/gmrs/yahoo_panel_invite.asp?a=7