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Re: CHPROP problems
- Subject: Re: CHPROP problems
- From: RMS at MIT-AI
- Date: Fri ,16 Aug 80 16:12:35 EDT
Here are some problems with CHPROP.
0) There is no function for turning a character
into a fixnum, or vice versa, assuming those data types are different.
These operations are important.
CHAR-CODE returns only part of the character.
1) There is no need for functions CHAR<, CHAR=, CHAR>.
The functions <, = and > should be used for this,
and they should be willing to compare a character
object with a number if those data types are different.
Having separate functions for comparison of characters
does not accomplish anything, because on systems which
implement characters with fixnums, they would be the same
as the fixnum comparison functions anyway, and on systems with
character objects there is no difficulty with making
the functions "<", etc., generic.
2) #/x is supposed to return a character object
if they exist. It sounds like people agree now
that this should not happen, so why not fix CHPROP?
3) #=nnn is superfluous when there is #/nnn.
4) The convention of a package called "*" seems like
a bad idea. I don't think the Lisp machine will adopt it.
5) Right now on the Lisp machine there is one sort of
character which can have bits and another which can
have a font. There is no sort which can have both.
It might be an improvement if there were, but it might
also be a lot of work. This might prevent the Lisp machine
from adopting CHPROP.