[plt-scheme] custom reader

[Robert Nikander]

Hi,

I hear you can define a custom reader for a custom language, to use  
like:

#lang my-language

Does documentation exist yet for doing this?  Or examples?

I looked at collects/swindle, because I noticed it parsed :keywords,  
but all I see is a minimal file in lang/reader.ss that makes no sense  
to me.

thanks,
Rob