bug#25425: cannot express search path

[ludo@gnu.org (Ludovic Courtès)]

Hello!

Ricardo Wurmus <rekado@elephly.net> skribis:

> Ludovic Courtès <ludo@gnu.org> writes:
>
>> I think this should work:
>>
>>        (search-path-specification
>>          (variable "LUA_PATH")
>>          (separator ";")
>>          (files '("share/lua/5.3"))
>>          (file-pattern "\\.lua$")
>>          (file-type 'regular))
>
> I tried this very same thing but it doesn’t work because Lua expects
> placeholders (“?”) in the search paths.  The placeholders are replaced
> with the actual package names.  If the actual file name does not exist
> it will try the next pattern.  If the file *does* exist – which *will* be
> the case for any of the files on LUA_PATH that have been generated by
> the search-path-specification — Lua will try to load the package from
> that path.
>
> This will fail because a search for the “lpeg” module would be satisfied
> by the file “re.lua”, because that’s the first valid file on the
> LUA_PATH.  “re.lua” requires “lpeg” itself, so another lookup is
> performed, which will again result in “re.lua” to be loaded…
>
> AIUI we must generate a value for LUA_PATH that keeps the placeholders
> intact.

So are you saying that it’s important for the question marks to remain
intact?

This sounds terrible.  I’m not sure how to address it, and I don’t feel
like stretching the search path mechanism this much.

Thoughts?

Ludo’.