[plt-scheme] Mutation of expansion time values not visible outside module

From: Noel Welsh (noelwelsh at yahoo.com)
Date: Thu Apr 6 00:22:15 EDT 2006

--- Matthew Flatt <mflatt at cs.utah.edu> wrote:

> The first time around, uses of the `add-val!' within the
> module are
> expanded, and they perform a side effect. But only the
> expansion result
> remains, so there's no effect for future compile-time
> runs.

Of course!  Thanks both to you and Robby, my understanding
of macros has inched up a bit.  Give me a century and I'll
master them! :-)


PS: I must admit some surprise no-one has scolded me on the
somewhat sleazy use of 3-D values.

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