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Re: Issue: EVAL-WHEN-NON-TOP-LEVEL (Version 5)
- To: KMP@STONY-BROOK.SCRC.Symbolics.COM, email@example.com
- Subject: Re: Issue: EVAL-WHEN-NON-TOP-LEVEL (Version 5)
- From: cperdue@Sun.COM (Cris Perdue)
- Date: Thu, 16 Feb 89 11:28:43 PST
- Cc: CL-Compiler@SAIL.Stanford.EDU, Moon@STONY-BROOK.SCRC.Symbolics.COM
My two bits worth:
All of Kent's examples of usage of EVAL-WHEN look like good
ones to me also. So do Sandra's examples.
Perhaps we need two proposals -- one compatible (or almost
compatible?) with CLtL, and one not.
The question of whether you would want to postpone
the action of a defmacro to loadtime is a red herring.
A more useful question is whether a programmer might reasonably want
to postpone *some* action normally done at compiletime so
it is done only at loadtime (using EVAL-WHEN). Even better
is the question of whether programmers should be able to
control exactly when forms get executed, even when they
themselves expand into EVAL-WHENs.
My answer to this last question is YES, so I favor full ability
to shadow inner EVAL-WHENs over greater compatibility with CLtL.
(EVAL-WHEN (:EXECUTE) . . . ) I don't know.