On 29/07/2023 08:37, LARONDE Thierry wrote: > 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? Yes, as file handling is of course not part of the portable TeX code. > Because in order to do > so, another primitive should be added? Why? The current behaviour is well defined. > Does LaTeX rely on a behavior that is not in the engines but only in the > web2c distribution? No, and we *don't here*: adding .tex is a feature of TeX not web2c. Joseph