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- To: common-lisp@su-ai
- From: Walter van Roggen <Walter.VanRoggen@CMU-CS-A> (C410WV50)
- Date: Wed, 08 Jun 1983 15:50:00 -0000
- - - - Begin forwarded message - - - -
Date: Wed, 08 Jun 1983 15:47:00 -0000
From: Walter van Roggen <Walter.VanRoggen@CMU-CS-A> (C410WV50)
To: David A. Moon <Moon%SCRC-TENEX%MIT-MC@SU-DSN>
Subject: Re: DEFCONSTANT
In-Reply-To: "David A. Moon's message of 7 Jun 83 21:16-EST"
Indeed, I have occasionally had problems with the compiler environment
getting altered undesirably; DEFMACRO has the same effects you describe.
Unlike what you say in (2), I believe that macros do get put into the
compiler's environment. So the potential problems with DEFCONSTANT as I
saw them are no different. In any case, I had hoped packages would
help avoid confusion when compiling the compiler or the lisp system.
But apparently the intent of DEFCONSTANT (according to Guy) is different
from all 4 options you list: it's like DEFPARAMETER with an implicit
declaration saying "if you can figure out what the value is without
changing the semantics (i.e., not copying), go ahead and use it, else
use the load-time value (which should be the same as just referring
to the special value, since it's constant)".
I'm happy with that definition. I just thought the one that corresponds
to DEFMACRO is also very useful and deserves its own name;.
- - - - End forwarded message - - - -
- From: Bernard S. Greenberg <BSG%SCRC-TENEX%MIT-MC@SU-DSN>