On Mon, 12 Feb 2001, David Carlisle wrote:
> 1) make every character active and look ahead to see if it is being
> followed by a combining char.
> This is possible and fun to code in TeX but I don't really think it
> is a long term stable solution.
> 2) use perl (or anything else) to detect all combining characters
> and replace them by some command placed before the base.
> This is quick and easy to arrange, but if you are having a perl
> pre-pass before TeX, it may as well go further and decode the
> entire character stream into "latex internal form" ie 7bit ascii tex
> markup. In which case we may as well stay with that markup as latexs
> internal form.
These two are not clean enough. That's the reason Omega OTPs exist. Yannis
and John disliked these two approaches. They now avoid active characters
as much as possible (eg '~' is not active anymore), and also avoid
pre-passes. Both solutions were needed when I was working on FarsiTeX: I
needed to pre-pass to do contextual shaping, and I needed active Tatweels
inserted between letters to stretch them to fit the line of text. I don't
need any of them now.
BTW, it seems that I have turned into a fan of Omega, without any big
experince with it, I've only played.