[plt-scheme] How to use a custom procedure as read?

Ali wrote:
> Hi,
> I'm sorry to ask this question, since it has been asked before, but I 
> could not make any sense of it at all.
> My query is fairly simple, and after an hour or two of searching and 
> trial and error, I hope I can get the answer an easier way here!
>
> Looked in the reference, this seems to be what I want, but all I'm not 
> sure exactly how to use it.
> http://docs.plt-scheme.org/syntax/reader-helpers.html#(part._module-reader) 
> <http://docs.plt-scheme.org/syntax/reader-helpers.html#%28part._module-reader%29>
>
> Read this and seemed to make sense, but not sure how to apply it to my 
> problem.
> http://www.htus.org/Book/Staging/how-to-use-modules/
>
> I believe the answer is in here, but again, I haven't been able to get 
> it working.
> http://groups.google.com/group/plt-scheme/browse_thread/thread/8aabfc15e0a392df/8a67d42dfcdadcae?lnk=gst&q=reader#8a67d42dfcdadcae 
> <http://groups.google.com/group/plt-scheme/browse_thread/thread/8aabfc15e0a392df/8a67d42dfcdadcae?lnk=gst&q=reader#8a67d42dfcdadcae>
>
> Problem:
> I've got a Scheme procedure which I would like to temporarily use as 
> the read procedure, eg.
>
> (swap-the-reader-in)
> ... code using custom reader ...
> (swap-the-reader-out)
> ... normal reader again ...
>
> My MzScheme version is 372. I'd be really grateful for an example of 
> how to temporarily use a custom procedure as the reader function.
> Thanks, Al


You should put `code using custom reader' in a separate module that use 
your own reader, and rest code in other (normal) modules. Hope you can 
figure out the rest on your own by reading the docs.

Chongkai