RE: [Haskell-cafe] Re: monad subexpressions

See also this thread http://www.haskell.org/pipermail/haskell-prime/2007-July/002269.html Magnus made a TH library that does something similar, see http://www.haskell.org/pipermail/haskell-prime/2007-July/002275.html Nesting is important. Consider do { a <- f x ; b <- g a ; return (2*b) } Then you'd like to linearise this to give do { return (2 * $(g $(f x))) } The hardest thing about this project is finding a suitable syntax! You can't use the same syntax as TH, but it does have a "splice-like" flavour, so something similar would make sense. $[ thing ] perhaps? Or %( thing )? Avoid anything that looks like a TH *quotation* because that suggests the wrong thing. (| thing |) is bad. A good plan can be to start a Wiki page that describes the problem, then the proposed extension, gives lots of exmaples, etc. Simon | -----Original Message----- | From: haskell-cafe-bounces@haskell.org [mailto:haskell-cafe-bounces@haskell.org] On Behalf Of Chris | Smith | Sent: 03 August 2007 04:30 | To: haskell-cafe@haskell.org | Subject: [Haskell-cafe] Re: monad subexpressions | | Neil Mitchell wrote: | > I think this is a fantastic idea, please do so! | > | | Okay, I'll do it then. If I have a good weekend, perhaps I'll volunteer | a talk at AngloHaskell after all! :) | | So what about syntax? I agree with your objections, so we've got | | ( <- expr ) -- makes sense, and I think it's unambiguous | ``expr`` -- back-ticks make sense for UNIX shell scripters | | The first is something Simon Peyton-Jones came up with (probably on-the- | fly) at OSCON, and I rather like it a lot; but I'm concerned about | ambiguity. The latter seems sensible as well. Any other ideas? | | -- | Chris Smith