dynamic scopes? fluids?

[Klaus Schilling]

Robert Brown writes:
 > I would like to ensure that my variable is accessible within the current
 > scope/environment as well as any scopes or within any invokations of
 > functions under this scope, but without making it "global" (current
 > top-level environment).  After doing some web searching, it seems that
 > "fluids" will do what I want.  Is this correct?  Can I just make a fluid,
 > set it, and then use fluid-ref anywhere "below" as is done with dynamic
 > scoping/bindings?

Is it possible to turn the whole current environment into a fluid, so
that a local-eval inside the fluid block can't alter the variables
at the top level when exiting the block?

Klaus Schilling