[tex-k] Potential bug in MF: missing output in transcript file & long diagnostics on terminal
dominik.leininger at t-online.de
Thu Aug 17 23:39:39 CEST 2023
I've come across the following strange behavior of MF, which doesn't
seem to be described in The MFbook, and therefore may not be intended
Running MF with `\ show tracingonline; show origin..right; end' (either
on the command line after `mf' or immediately after `**') will give the
>> Path at line 0:
(0,0)..controls (0.33333,0) and (0.66667,0)
Transcript written on mfput.log.
According to `>> 0', the path should not be displayed on the terminal,
but it does. The second thing I noticed is that you should see the path
in the transcript file, but mfput.log only contains the following line
after the MF's welcoming:
**\ show tracingonline; show origin..right; end
If you just type \ after **, hit enter and then type the show command
after the single `*', everything works as expected.
Note that the transcript file also lacks the output of message commands
when used immediately after `**':
**\ message "A";
**\ message "A";
I also checked picture variables (`\ show unitpixel;') and pen variables
(`\ show pensquare;') for tracingonline:=0 (which is default).
I also checked for tracingonline:=-1.
I tested on Windows 10 (METAFONT, Version 2.71828182 (TeX Live 2023))
and Ubuntu 22.04 (also METAFONT, Version 2.71828182 (TeX Live 2023)).
What am I missing here? Is this behavior intended? If so, I cannot find
a description of it in The MFbook. The behavior feels strange,
especially that the transcript file does not include the output of
show/message commands when used immediately after `**'. My understanding
is that everything after `**\' should behave the same as after `*'.
Summary of unexpected behaviors:
- output of message and show commands immediately after `**' (or after
`mf \' in the command line) don't get logged in the transcript file.
- paths, pens and pictures are shown on the terminal even though
tracingonline<=0 when the show command is used immediately after `**'
(or after `mf \' in the command line)
Has anyone experienced this behavior or can anyone reproduce it?
Thanks and best regards,
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