[tex-live] epTeX weirdness with \numexpr

[Philip Taylor (RHUoL)]

My TeX Live 2018 does not appear to include eplatex :  ptex is known, 
eptex -- ditto --, but not eplatex.  If I invoke epLaTeX the 
old-fashioned way, the system fails to find the format file that it 
seeks to create :

eptex -ini  ^&latex untitled-1
This is e-pTeX, Version 3.14159265-p3.8.0-180226-2.6 (utf8.sjis) (TeX 
Live 2018/
W32TeX) (INITEX)
  restricted \write18 enabled.

kpathsea: Running mktexfmt latex.fmt

The command name is D:\TeX\Live\2018\bin\win32\mktexfmt
Running the command D:\TeX\Live\2018\bin\win32\fmtutil-user.exe

...

No pages of output.
Transcript written on latex.log.
fmtutil [INFO]: c:/users/philip 
taylor/.texlive2018/texmf-var/web2c/pdftex/latex
.fmt installed.
fmtutil [INFO]: Disabled formats: 6
fmtutil [INFO]: Successfully rebuilt formats: 1
fmtutil [INFO]: Not selected formats: 43
fmtutil [INFO]: Total formats: 50
fmtutil [INFO]: exiting with status 0
Sorry, I can't find the format `latex.fmt'; will try `eptex.fmt'.
entering extended mode
(./untitled-1.tex
! Missing ) inserted for expression.
<to be read again>
                    \relax
l.2 \message{\test{ 0 + ( 1 + 2 }
                                  }

Philip Taylor
--------
> Yes, that's because you are almost certainly using plain not LaTeX. 
> You can get the same error in plain if you load more 'stuff' (or at 
> least if you load the generic version of expl3).
>
> Joseph
>