On Sat, Jul 29, 2023 at 08:07:54AM +0100, Joseph Wright wrote:
> On 29/07/2023 06:46, LARONDE Thierry wrote:
> > On Fri, Jul 28, 2023 at 08:31:53PM +0100, David Carlisle wrote:
> > > 
> > > % If this option is set to true, `tex a.b' will look first for a.b.tex
> > > % (within each path element), and then for a.b, i.e., we try standard
> > > % extensions first.  If this is false, we first look for a.b and then
> > > % a.b.tex, i.e., we try the name as-is first.
> > > %
> > > % Both names are always tried; the difference is the order in which they
> > > % are tried.  The setting applies to all searches, not just .tex.
> > > %
> > > % This setting only affects names being looked up which *already* have
> > > % an extension.  A name without an extension (e.g., `tex story') will
> > > % always have an extension added first.
> > > %
> > > % The default is true, because we already avoid adding the standard
> > > % extension(s) in the usual cases.  E.g., babel.sty will only look for
> > > % babel.sty, not babel.sty.tex, regardless of this setting.
> > > try_std_extension_first = t
> > 
> > I suppose that this behavior is in LaTeX code, not an engine?
> 
> That's from texmf.cnf, so affects most engines. (LuaMetaTeX like unaffected:
> I'd have to check.)

This does mean that this behavior is not in the engine but in the glue
code (the opening routines implemented in web2c/kpathsea)? So its
setting is done at configuration level in the distribution, and LaTeX
has no way to switch things from its macro files? Because in order to do
so, another primitive should be added?

Does LaTeX rely on a behavior that is not in the engines but only in the
web2c distribution?
-- 
        Thierry Laronde <tlaronde +AT+ polynum +dot+ com>
                     http://www.kergis.com/
                    http://kertex.kergis.com/
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