[Fontinst] eTeX and fontinst -- incompatible?

[Lars Hellström]

At 21.02 +0100 2003-12-08, Walter Schmidt wrote:
>Hi!
>
>it seems not to be possible to process fontinst scripts using
>eTeX.  A simple script such as
[snip]
>fails, apparently during the \installfont command:
>
>  ! Missing number, treated as zero.
>  <to be read again>
>                     \i-rawscale
>  \setscaledrawglyph ...unt =\int {rawscale}
>                                            \multiply \a_count \e_count...
[snip]
>This happens with both VTeX and MikTeX. (I have no teTeX
>available here.)   Is this a bug or a feature, or did I
>make any mistake?

This could indeed be a bug. The thing is, fontinst actually tries to take
advantage of the eTeX primitive \ifcsname (when it is defined) to implement
the \if_defined and \if_undefined conditionals, which in turn are used to
implement e.g. \ifisint.

Maybe there is a difference between \unless\ifcsname #1\endcsname (eTeX)
and \expandafter\ifx \csname #1\endcsname\relax (TeX). I'll have to look
into it.

Lars Hellström

PS: I see from your later mail that Heiko Oberdiek indeed confirms my
suspicions above. Probable fix is then to be more careful about how things
are \unset (\let...=\relax is not OK, but \let...=\undefined_command should
be).