Nick Beaudrot  <niq@techhouse.brown.edu> wrote:
+---------------
| I'm trying to find an implementation of scheme that supports multiple
| interpreters running at the same time in the same process 
| (but in different threads). This is so that each thread can have
| different definitions of certain procedures.
+---------------

Take a look at MzScheme <URL:http://www.cs.rice.edu/CS/PLT/packages/
mzscheme/index.html>, not only at the thread stuff but also at
"namespaces" and "parameterizations", both of which are per-thread.
In particular, as it says in the docs under "Global Variable Namespaces":

	The current namespace is used by eval, load, compile, and
	expand-defmacro. Once an expression is evaled or compiled,
	the global variable references in the compiled expression
	are permanently attached to a particular namespace, so the
	current namespace at the time that the code is executed is
	*not* used as the namespace for referencing global variables
	in the expression.

I suspect that can be used to do what you want.


-Rob

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