fonts in CLtL

[Masinter.pa@Xerox.ARPA]

Are there any implementations which use a value of CHAR-FONT-LIMIT other
than 1, or a non-vacuous definition for CHAR-FONT? If not, could we
remove this feature from the language? (Under the theory that "optional"
features which no implementation uses should be removed from the
specification.)

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Date: Tue, 17 Dec 85 20:43 EST
From: David A. Moon <Moon@SCRC-STONY-BROOK.ARPA>
Subject: fonts in CLtL
To: Daniel L. Weinreb <DLW@SCRC-QUABBIN.ARPA>, masinter.pa
cc: rpg@SU-AI.ARPA, sybalsky.pa
In-Reply-To: <851216230521.4.DLW@CHICOPEE.SCRC.Symbolics.COM>
Message-ID: <851217204330.5.MOON@EUPHRATES.SCRC.Symbolics.COM>

    Date: Mon, 16 Dec 85 23:05 EST
    From: Daniel L. Weinreb <DLW@SCRC-QUABBIN.ARPA>

	Date: 16 Dec 85 15:11 PST
	From: masinter.pa@Xerox.ARPA

	It was my impression looking over the latest Symbolics documentation
	that Symbolics has moved away from using font-bits in characters. We've
	found them impossible -- they don't contain enough information. If
there
	aren't any other implementations that use font-bits, maybe we could get
	rid of them.

	I thought I'd ask privately before broadcasting.

    Yes, I proposed this recently and I think that we have agreed to do
it.
    Our model of character styles does not include any mapping from
integers
    to styles (fonts) that is suitable for Common Lisp's model of the
font
    attribute.  (There is a mapping, but its lifetime is only over one
Lisp
    environment, so it would be meaningless to say #3\A in a file.)

    (I've CC'ed Moon so he can correct me if necessary.)

The above is all correct.  CHAR-FONT-LIMIT will be 1 in our next
release, CHAR-FONT will always return 0, and we will have a field in
characters, whose value is an instance rather than an integer, that
doesn't pretend to be any of the Common Lisp character fields.

NB: None of this has anything to do with CHAR-BITS, which we make good
use of.


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