Re: *Why* are precomposed characters required for "backward

From: James E. Agenbroad (
Date: Wed Jul 10 2002 - 14:42:24 EDT

On Wed, 10 Jul 2002, John Cowan wrote:

> James E. Agenbroad scripsit:
> > The standards I cited use both
> > techniques (precomposed and decomposed letter+diacritic) but they don't
> > allow two ways of creating a single letter+diacritic combination the way
> > ISO10646/Unicode do.
> Even Unicode doesn't go so far as to decompose WITH STROKE.
> In fact, I would argue that the COMBINING HORN was a mistake. It would
> have been only slightly less efficient to include O WITH HORN and U WITH
> HORN (uc and lc) as undecomposable letters; HORN is really not a diacritic
> but a modification of the ordinary O and U.
> --
> John Cowan <>
> Yakka foob mog. Grug pubbawup zink wattoom gazork. Chumble spuzz.
> -- Calvin, giving Newton's First Law "in his own words"
                                                  Wednesday, July 10,2002
     I think back in the late 60's the justification for how the
library character set was designed was that (except for cedilla) if the
diacritic/modifier visually touched the letter the combination had its own
code, if it didn't the diacritic had its own code.
     It's may also be worth noting that codes for separate diacritics
preceded the letter they modified following manual typewriter "dead key"
practice. We weren't far-sighted enough to see that this would have led
to chaos with some other scripts. It also makes conversion between Unicode
and U.S. library encoding practices more "challenging". (The less said
about Vietnamese the better.)
          Jim Agenbroad ( )
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grow old, they grow old because they stop pursuing their dreams." Adapted
from a letter by Gabriel Garcia Marquez.
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