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Re: Issue: DECLARE-TYPE-FREE (Version 9)
- To: Kent M Pitman <KMP@STONY-BROOK.SCRC.Symbolics.COM>
- Subject: Re: Issue: DECLARE-TYPE-FREE (Version 9)
- From: masinter.pa@Xerox.COM
- Date: 3 Jan 89 11:35 PST
- Cc: masinter.pa@Xerox.COM, Moon@STONY-BROOK.SCRC.Symbolics.COM, CL-Cleanup@SAIL.STANFORD.EDU
- In-reply-to: Kent M Pitman <KMP@STONY-BROOK.SCRC.Symbolics.COM>'s message of Tue, 3 Jan 89 01:31 EST
Well, I think it is enforcable, if you have specialized storage.
I think the direction of your inference is backward. ALLOW is more powerful
than LEXICAL. A program that is correct using ALLOW semantics remains
correct using LEXICAL semantics. Thus, an implementation that can only
enforce LEXICAL will still accept programs that are correct under ALLOW.
The converse is not true.
Thus, ALLOW is more restrictive, and it allows implementations more
freedom, while not putting any unreasonable constraints on programs that
want to use declarations.