Re: Bawden's remarks on characters

[Mike McMahon <MMcM at MIT-AI>]

    Date: 15 August 1980 1739-EDT (Friday)
    From: Guy.Steele at CMU-10A
    Yes, adding 23. to #/A to get #/X is a neat crock.  Writing
    (CODE-CHAR (+ 23. (CODE-CHAR #/A))) is not that much more work,
    is clearer as to what is going on, and no less efficient when
    compiled (on the LISP Machine CODE-CHAR and CHAR-CODE are probably
    identity macros -- but by putting in the calls to identify the explicit
    coercions we give the code half a chance of being compatible witrh
    other implementations).

(CHAR-CODE (+ 23. (CODE-CHAR #/A))) is #/Q in EBCDIC.  #/A is 301 and
#/X is 347.  In other words, the new functions haven't gained you
anything in transportability of code that chooses to do character
arithmetic.  What we have here it a solution in search of a problem.