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[Sigh, the mailer barfed the first time I tried sending this...]

> Date: Mon, 26 Sep 88 18:13:54 EDT
> From: Dan L. Pierson <pierson%mist@multimax.ARPA>
> Would this (and other) problems be reduced if we defined a
> code-walking primitive and required it in the language?  Would this
> reduce Sandra's objection to forcing all interpreters to do a pre-pass?

My experience with code-walking primitives is that they don't work.  I
wrote one a few years ago that had all sorts of hooks in it to be as
general as possible.  I was actually using it for a while to implement
something similar to WITH-SLOTS.  Shortly afterwards, a group of us
here at Utah had a need for a code walker to do various kinds of
source-to-source transformations for PCLS.  Turns out my codewalker
was useless and they ended up writing specialized processors for each
pass.  Another person here tried again later with the same results.
Of course, I'd be much less skeptical if you came up with a specific
proposal and I found that I could actually use it for some of the
things I'm doing a code walk for now.

Also, it really isn't "my" objection to forcing interpreters to do a
pre-pass; I'm willing to go along with it if everybody else is.  I've
merely stated that it would be an incompatible change to the language
and a substantial change for implementations that don't already do
things that way.  Also, I know that some users (including a number of
people here at Utah) really hate implementations that do a pre-pass.