Re: require() relative to calling file

[Javier Guerra Giraldez <javier@...>]

On 7 February 2017 at 02:23, Stephen Irons <stephen.irons@clear.net.nz> wrote:
> However, in the source code, it is package.searchpath() (file
> loadlib.c, function searchpath()) that implements the way Lua finds
> modules. searchpath() modifies the name of the module to find
> (replacing '.' with the directory separator), then takes a list of
> path templates (from package.path), replaces '?' with the modified
> name of the module, and passes each in turn to the C standard function
> fopen(). This code is all very straightforward, with no special cases.
>


What I would like is that package.searchpath() would replace another
character, like '$' with the directory where the function calling
'request' resides. a crude implementation:

--------------
local function getcallingdir(lvl)
    for i = (lvl or 2), 1000 do
        local fi = debug.getinfo(i, 'S')
        if not fi then break end
        if fi.source and fi.source:sub(1,1) == '@' then
            local fname = fi.short_src or fi.source:sub(2)
            return fname:match('^(.*)/[^/]*$') or fname
        end
    end
end

local oldsearch=package.searchpath

function package.searchpath (name, path, sep, rep)
    local calldir = getcallingdir(3)
    if calldir then
        path = path:gsub('%$', calldir)
    end
    return oldsearch(name, path, sep, rep)
end
-----------------------

something like this would make it easy to write multi-source-file
packages that can be installed anywhere, or even used as a "private"
part of a bigger bundle.  a "main" file could require() other
submodules with relative paths from itself, instead of having to
specify the whole path or making all pieces directly visible to all
scripts.


-- 
Javier