Thanks Matthias and Sam, the macro expansion now works as I intended, with
the following change:
(define-syntax-rule (with-monad (<unit-f> <bind-f>) <body>)
(let ((u <unit-f>)
(b <bind-f>))
(syntax-parameterize ([bind (make-rename-transformer #'b)])
(syntax-parameterize ([unit
(make-rename-transformer #'u)])
<body>))))
2011/7/19 Sam Tobin-Hochstadt <sa...@ccs.neu.edu>
> On Tue, Jul 19, 2011 at 2:06 PM, Ismael Figueroa Palet
> <ifiguer...@gmail.com> wrote:
> > Hi all, I'm trying to implement some simple macros to use monads in
> racket
> > using a Haskell-like do notation. I have the following macros, and my
> > problem is that I want the do macro to capture the bind identifier
> created
> > by with-monad, and in each recursive step of the do macro expansion keep
> the
> > same identifier. I don't know it is possible, I tried using (with-syntax
> > ((bind (datum->syntax 'bind) ))) but it doesn't work.
>
> I think the right solution here is to use syntax parameters [1]. This
> blog post by Eli provides a good intro:
> http://blog.racket-lang.org/2008/02/dirty-looking-hygiene.html
>
> [1] http://docs.racket-lang.org/reference/stxparam.html
> --
> sam th
> sa...@ccs.neu.edu
>
--
Ismael
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