Danny, Jens Axel, Ian, Ray, Thanks for your input... I'm absorbing it all.
I need some really basic help getting my head around all of this. Where can I download a copy of "How to Design Macros"? :-) Tim On 16/01/13 17:22, Jens Axel Søgaard wrote:
Hi Tim, Danny explains the problem well. To accumulate a result, one must stay in the same same dynamic extent. One way to solve the problem is to use local-expand. In some cases one can write expanders for the forms, that needs analysing and call them directlye (rather than write a macro for the subform and then let the expander call a macro transformer). Below is a short example, which incidently shows an alternative solution the local-expand problem, I had the other day (see http://www.mail-archive.com/users@racket-lang.org/msg15937.html ). If you need local-expand, then see Matthews answer on how to use definition contexts with local-expand. /Jens Axel
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