# [luatex] Logging of font names in box log output

Hans Hagen pragma at wxs.nl
Tue Sep 8 22:22:19 CEST 2015

On 9/8/2015 9:49 PM, David Carlisle wrote:
> Hi I have a feeling this has come up before, but  the plain tex file
>
>
> \font\a=cmr10
> \font\b=cmr10
>
> \setbox0\hbox{\a x\b y}
> \scrollmode
> \tracingonline1
> \showbox0
> \bye
>
>
> produces a log of
>
> ..\b x
> ..\b y
>
>
>
> in tex/pdftex/xetex/ptex/uptex
>
> but in luatex it produces a log of
>
> ..\a x
> ..\b y
>
> This is a major problem for the latex regression suite as it is very
> hard to normalize out (as we do for the direction logging difference
> where
> "direction TLT" in luatex or  "yoko direction" in  ptex occur in
> well defined places and can be factored into the comparison).
>
> Would it be possible for luatex to match other tex variants and log
> font names by the last name under which the font was loaded?

luatex doesn't have the same low level font loading / sharing code; in
fact it is (pdf)tex that is weird in printing \b for \a and the logging
in luatex is right (one of things we made sure of, as this confusing

also, be prepared for more differences in logging as log compatibility
is not guaranteed (esp when we have cleaned up that bit)

you cannot even assume that luatex has the same output as pdftex (i.e.
slightly different hyphenation and ligaturing code), again, we try to be
very compatible but when we can make things cleaner (or better, for what
it's worth, often meaning: removing an optimization or limitation no
longer needed) we'll do it

an option (for you) is to just ignore the font name (or patch your font
switch macro to write something to the log that you can compare)

Hans

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