[Fontinst] Re: \glyph_parameter change proposal

[Vladimir Volovich]

"LH" == Lars Hellström writes:

 >> it is possible that there is a need to refer to glyph metrics for
 >> unencoded glyphs - e.g. when re-encoding the font to OT2 encoding,
 >> one may still wish to be able to access the \height{x} to set
 >> fontdimen parameters;

 LH> One can already do this by saying \height{x-not}.

but i cannot know in advance whether the glyphs x is encoded or not,
so i will then have to bloat the code with
\ifisglyph{x}\then\height{x}\else\height{x-not}\fi
instead of just \height{x}

 LH> But wouldn't the height of "cyrillic small letter ha" (U+0445) be
 LH> more appropriate in this context?

for xheight, it might me the case (although it still might be good to
refer to x since all latin letters are usually also present in
cyrillic fonts), but for other parameters (e.g. ascender and
descender) i don't know which cyrillic glyphs would be right to use
instead of d and g respectively.

 >> or when building faked glyphs, it might me useful to refer to
 >> glyph metrics of some other glyphs which might me unencoded.

 LH> Again, it is already perfectly possible to do this. But you (as
 LH> the author of an MTX file) have to bother to explicitly access
 LH> the metrics of this unencoded glyph.

understood; though it makes the code unnecessarily bloated (or
requires one more macro)...

 >> will the proposed change to the \glyph_parameter command have some
 >> undesired effects? if not, why not change it? :)

 LH> As I explained, the proposed change does indeed have undesired
 LH> effects, for example because of the \edef that \glyph_parameter
 LH> needs to survive.

no - the proposed \glyph_parameter perfectly survives in all cases
when the current \glyph_parameter survives.

do you know of any other undesired effects?

Best,
v.