Will Robertson wrote:
> On 07/12/2008, at 8:55 AM, Arno Trautmann wrote:
> 
>> I think, it’s only a tiny typo, but confused me some minutes: On page 17
>> of l3basics, version 2008/11/24, there is the description of
>> \engine_if_etex: which says
>> ”This function detects if we’re running an Aleph-based format.“
>> It should be ”running an eTeX format“, shouldn’t it?
> 
> Yes, silly typo by me :)
> This command will probably end up being removed, and an error called if
> eTeX is not being used -- it's too hard (or impossible, for somethings)
> not to use the extended features that eTeX offers.

Just to point out (again) that I don't see any test in expl3 for eTeX,
even though the extensions are required (see for example
\tlp_put_right:, where \unexpanded is used).  Surely l3names should have
something like

\begingroup
  \@ifundefined{eTeXversion}{%
    \PackageError{l3names}{Not running under e-TeX}
      {This package requires e-TeX. Try compiling the document with
       \MessageBreak `elatex' instead of `latex'. When using pdfTeX, try
       `pdfelatex' \MessageBreak instead of `pdflatex'}%
     \endgroup\endinput
  }{%
    \endgroup
}

near the beginning.
-- 
Joseph Wright