Re: [Groff] unicode support - where to compose?

[Bruno Haible]

Hello Werner,

> > So I imagine that noone will object if troff combines
> >
> >              x\[u0302]\[u0301]
> > into
> >              \[u0078_0302_0301]
>
> I think this is OK.  Currently, there is a single non-spacing glyph
> used in groff (`slashnot' in devdvi; the other non-spacing glyphs from
> the various DVI fonts have no names), and this has to be placed before
> the base character.  Additionally, it isn't a valid Unicode character
> so there is no conflict.

Does the separator need to be a glyph? I haven't looked yet how exactly
\& works, but for most devices I expect it to be an input node, but not
a glyph.

> I've thought that you suggest to handle
>
>   <U+0078><U+0302><U+0301> -> \[x u0302 u0301]
>
> in preconv, and
>
>   x\[u0302]\[u0301] -> \[x u0302 u0301]
>
> within groff.

Actually I want to do one _or_ the other. If it's done inside troff, there
is no need to do it in preconv as well.

> The latter is quite
> complicated -- the node merging code in GNU troff is, well, not easy
> to understand --

I'll try to put it there nevertheless, because composed characters in
Unicode are a concept similar to ligatures; I would like to avoid implementing
two similar things in two very different ways.

Bruno