[R6RS] `eqv?' on immutable records

William D Clinger will at ccs.neu.edu
Tue May 15 14:23:20 EDT 2007

Kent wrote:
> What I meant was that programmers can perform a
> transformation that apparently violates the language semantics but doesn't
> actually because of knowledge the programmer has about the program.  For
> example, a programmer may know that a program doesn't apply eq? or eqv?
> to any quoted constants or procedures, allowing the use of ordinary beta
> substitutions, even if the semantics would not otherwise support that use.

There is no difference here between programmers and
automated tools.

What you are advocating is a semantics that adds new
side conditions to the beta rule, which reduces the
number of transformations that are legal, and also
makes the legal ones more difficult to justify.

You can rationalize that however you want, but that's
what you're doing.


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