[plt-scheme] reduction-semantics with multiple languages

From: Jacob Matthews (jacobm at cs.uchicago.edu)
Date: Mon Mar 14 17:19:19 EST 2005

Martin Gasbichler wrote:

>The term (- 27) should have only one possible reduction in
>LANG. However, if LANG2 is defined as above (and before LANG) the
>tracer shows two possible reductions in LANG (27 and -27). The system
>obviously uses LANG2's definition of X. Changing the definition of the
>non-terminal X in LANG2 to LANG's definitions fixes the problem. I
>don't think it's intensional that the definitions of the languages
>affect each other. I'm using PLT 208p1. Can anybody tell me what's
>going wrong here?
This is a bug that existed for a long time but was fixed recently. The 
version of PLT Redex in CVS has the bug fixed.


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