Re: input 39 in ansinew.def

[Berthold Horn <bkph@ai.mit.edu>]

At 05:27 PM 10/30/98 +0000, Chris Rowley wrote:

>Berthold wrote --

>> Good rules.  And easy to live by if you are on a system that uses ASCII

>Yes, character encodings incompatible with 7-bit printable ascii are
>impossible for us at present.  This is due to the fundamentals of the
>way Don Knuth set-up TeX and which we do not have the time (or skill?)
>to change right now.

I think the natural way to deal with such encodings is via an input remapping
(8-bit number to 8-bit number) option in the TeX implementation and/or
an input replacement (8-bit number to TeX code string).  Several
TeX implementations provide such capabilities.

>I had only recently realised that ANSI is not ASCII-compatible 
>(add usual grumble about things emerging from A:-).

You are focusing on the wrong letter :-) The problem is the `S' in 
ASCII and ANSI.  Still, give them credit for not adopting EBCDIC!

>I still think that the IS0-LATINs are but I am probably wrong.

Err, no.  Windows ANSI is a superset of ISO Latin 1.  Hence ISO Latin 1
is not `compatible' with ASCII either (Neither is Macintosh standard roman 
encoding).

By the way, keep in mind that there is the actual ISO standard and then
there are de facto ISO's where people have `done the right thing' to fix
some of the bugs.  The actual ISO standard is a bit odd.  Here are some
of the tricky points:

=27     U+0027  APOSTROPHE	is this quotesingle? or something else?

=2D     U+002D  HYPHEN-MINUS	well, which is it? de facto it is hyphen...

=5E     U+005E  CIRCUMFLEX ACCENT	not asciicircum as in ASCII

=60     U+0060  GRAVE ACCENT	not quoteleft, sigh...

=7E     U+007E  TILDE ACCENT	not asciitilde as in ASCII

There is more higher up 160-255, but this may not be relevant here.

>> Unicode.

>If this is not ascii-compatible then "We" need to revise both LaTeX
>and Plain TeX or even Plain eTeX pdq!

Yes.  Unicode is a super set of ISO Latin 1.  So it is not ASCII compatible.

>>  And once you get rid of all the unneccesary use of octal 
>> notation it actually doesn't interfere too badly with most style files.

>Now this is something we have gone to some trouble to remove, in the
>sense that we do not use it ourselves and no one else needs to use it.

I noticed. Thank you.  Great!

Berthold.