bug in fontinst 1.801: duplicated kernings (was: ae fonts Q)

[Vladimir Volovich]

"LH" == Lars Hellström writes:

 LH> This complicates things. One would still want the exclusive
 LH> behaviour for fonts that should be used with normal TeX.

 >> The new ligature/kerning builder is able to first create ligatures
 >> (ignoring all kerning instructions in the font's lig/kern table)
 >> and then insert appropriate kerning between the resulting char
 >> resp. ligature nodes (ignoring all ligature instructions).  As one
 >> positive side effect of the new routines this will allow you to
 >> insert kerning between two ligatures which is currently not
 >> possible with TeX.
[...]
 LH> Hmm... Due to the fact that it primarily is normal TeX that
 LH> should be supported, I believe it actually would be simpler to
 LH> implement a version that would impose the one ligature limit as
 LH> well (i.e., as you described above). Switching between normal TeX
 LH> settings and e-TeX settings can be simplified to redefining one
 LH> control sequence.

as far as i understand, implementing different fontinst behavior (for
original TeX and for e-TeX) is not needed: it is sufficient (and more
simple/preferable) to implement just the discussed extension to
fontinst. The original TeX anyway will not be able to use these
extended kerning features, will it? So, e.g. if some _font_ contains
kern between two ligatures, and this font is loaded by "original" TeX,
then TeX will behave exactly like it did before (i.e. it will be able
to create ligatures and will not be able to insert a kern between
them). But e-TeX being feeded with the _same_ font, will benefit of
this? Or am i wrong?

	Best regards, -- Vladimir.