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Requested changes to R4RS
[Cc: Scheme-Standard deleted]
Date: Thu, 25 May 89 02:19:56 -0700
From: "Jonathan S. Shapiro" <email@example.com>
I think the peek-char debate centered around what peek-char's behavior
was in the face of rubout handlers, which evolved from the discussions
about char-ready?. The problem is that if we can't define the
semantics for char-ready?, a good argument can be made that for the
same reasons we can't define the semantics of peek-char. If it was
there to be peeked at, and we can define what that means, then we can
surely define what char-ready? means.
We need some suitable primitive to permit the construction of portable
readers. Right now there is now way a user can write READ or anything
similar because there is no way to find out when you've encountered
the end of a symbol or number without gobbling the character that
delimits then symbol or number. I don't care what the primitive is.
It doesn't have to be PEEK-CHAR, but we've got to have it. Don't
just argue against PEEK-CHAR; explain how we can solve the READ problem.
I think CHAR-READY? is a much less interesting and important question.
If it is made possible by progress on the READ problem, fine, but
that's a secondary issue.
What does X3J13 Common Lisp say about the interaction of PEEK-CHAR and