-- lualoader.lua: make LuaTeX's "require" behave more like Lua's
-- This file:
-- http://angg.twu.net/dednat6/dednat6/lualoader.lua
-- http://angg.twu.net/dednat6/dednat6/lualoader.lua.html
--         (find-angg "dednat6/dednat6/lualoader.lua")
-- By Eduardo Ochs <eduardoochs@gmail.com>
-- Version: 2022apr22
--
-- Loaded by:
--   (find-dn6 "dednat6.lua" "luatex-require")
--   (find-dn6 "dednat6.lua" "luatex-require" "lualoader")
-- Also here:
--   (find-angg "LUA/DednatRequire1.lua")

-- IMPORTANT: before april/2022 this file defined a function called
-- "dednatlualoader" and inserted it in the table package.searchers...
-- This approach was fragile, and buggy. Luatex includes this file in
-- its core:
--
--   https://github.com/latex3/lualibs/blob/main/lualibs-package.lua
--
-- and that file has this comment near its top:
--
--   "We overload the regular loader"
--
-- It turns out that that file redefines the table package.searchers
-- in a way in which the numbering of the entries is important. I was
-- doing this,
--
--   table.insert(package.searchers, 2, dednatlualoader)
--
-- which was making the entry 3 become the entry 4, the entry 4 become
-- the entry 5, and so on... my "table.insert" was causing subtle
-- bugs, and as I didn't understand the code of lualibs-package.lua
-- well I couldn't fix them.



-- «.compatibility»		(to "compatibility")
-- «.DednatRequire»		(to "DednatRequire")
--
-- Obsolete code:
--   «.dednatlualoader»		(to "dednatlualoader")
--   «.adddednatlualoader»	(to "adddednatlualoader")
--   «.temporary-fix»		(to "temporary-fix")



-- «compatibility»  (to ".compatibility")
-- Compatibility stuff.
-- See: http://www.lua.org/manual/5.1/manual.html#pdf-package.loaders
--      http://www.lua.org/manual/5.2/manual.html#pdf-package.searchers
--      http://www.lua.org/manual/5.1/manual.html#pdf-loadstring
--      http://www.lua.org/manual/5.2/manual.html#8.2 loadstring is deprecated
--      http://www.lua.org/manual/5.2/manual.html#8.2 .loaders -> .searchers
package.searchers = package.searchers or package.loaders
loadstring = loadstring or load



-- «DednatRequire»  (to ".DednatRequire")
-- Experimental, 2022apr22.
-- Note: my "real" classes are defined like this:
--
--   ClassName = Class { ..., __index = { ... } }
--
-- This is a "fake" class, that doesn't have __index,
-- and doesn't have a metatable. See:
--
--   http://angg.twu.net/LUA/eoo.lua.html
--   http://angg.twu.net/LUA/eoo.lua
--           (find-angg "LUA/eoo.lua")
--
oldrequire = oldrequire or require

DednatRequire = {
  --
  -- Method 0:
  alreadyloaded = function (modulename)
      if package.loaded[modulename] then
        return package.loaded[modulename]
      end
    end,
  --
  -- Method 1:
  findandload = function (modulename)
      local filename = DednatRequire.find(modulename)
      if not filename then return nil end
      return DednatRequire.loadfile(modulename, filename)
    end,
  find = function (modulename)
      local modulepath = string.gsub(modulename, "%.", "/")
      for path in string.gmatch(package.path, "([^;]+)") do
        local filename = string.gsub(path, "%?", modulepath)
        local file = io.open(filename, "rb")
        if file then
          file:close()
          return filename
        end
      end
    end,
  loadfile = function (modulename, filename)
      local runcode = assert(loadfile(filename))   -- the file must exist
      local retval = runcode()                     -- and this must succeed
      package.loaded[modulename] = retval or _G    -- mark as loaded
      return package.loaded[modulename]
    end,
  --
  newrequire = function (modulename)
      return DednatRequire.alreadyloaded(modulename) -- try the method 0
          or DednatRequire.findandload(modulename)   -- try the method 1
          or oldrequire(modulename)                  -- try the oldrequire
    end,
  --
  usenewrequire = function ()
      require = DednatRequire.newrequire
    end,
}


-- The default action of the block below is to replace the "old
-- require" by a "new require" that is a wrapper around the "old
-- require" (see above).
--
if adddednatlualoader == nil then   -- The default is to
  DednatRequire.usenewrequire()     -- use the new require
else
  adddednatlualoader()              -- Alternative action
end



-- Old code, commented out:
-- 
-- -- «dednatlualoader»  (to ".dednatlualoader")
-- -- Based on: http://lua-users.org/wiki/LuaModulesLoader
-- -- See: http://tug.org/pipermail/luatex/2015-February/005071.html (problem)
-- --      http://tug.org/pipermail/luatex/2015-February/005073.html (solution)
-- --      (find-es "luatex" "require")
-- dednatlualoader = function (modulename)
--     local errmsg = ""
--     -- Find source
--     local modulepath = string.gsub(modulename, "%.", "/")
--     for path in string.gmatch(package.path, "([^;]+)") do
--       local filename = string.gsub(path, "%?", modulepath)
--       local file = io.open(filename, "rb")
--       if file then
--         -- Compile and return the module.
--         -- Was:
--         --   return assert(loadstring(assert(file:read("*a")), filename))
--         -- but due to this issue,
--         --   http://tug.org/pipermail/luatex/2017-July/006589.html
--         --   http://tug.org/pipermail/luatex/2017-July/006590.html
--         -- I had to change it to:
--         file:close()
--         return assert(loadfile(filename))
--       end
--       errmsg = errmsg.."\n\tno file '"..filename.."' (checked with custom loader)"
--     end
--     return errmsg
--   end
-- 
-- 
-- 
-- -- «adddednatlualoader»  (to ".adddednatlualoader")
-- -- The default action is to add dednatlualoader to package.searchers,
-- -- but the "if" below lets me hack that while I don't I find a solution
-- -- to this problem:
-- --   https://tug.org/pipermail/luatex/2020-November/007426.html
-- --   https://github.com/latex3/lualibs/issues/4
-- if adddednatlualoader then
--   adddednatlualoader()
-- else
--   table.insert(package.searchers, 2, dednatlualoader)
-- end
-- 
-- 
-- 
-- -- «temporary-fix»  (to ".temporary-fix")
-- -- % If you are using TeXLive/MikTeX/whateverTeX 2020
-- -- % and dednat6 doesn't work there, a ___TEMPORARY SOLUTION___
-- -- % is to install a new dednat6 from
-- -- % 
-- -- %   http://angg.twu.net/dednat6.zip
-- -- % 
-- -- % and then add this to your .tex file:
-- --
-- -- \directlua{adddednatlualoader = function ()
-- --     require = function (stem)
-- --         local fname = dednat6dir..stem..".lua"
-- --         package.loaded[stem] = package.loaded[stem] or dofile(fname) or fname
-- --       end
-- --   end}
-- --
-- -- % just before the:
-- --
-- -- \catcode`\^^J=10
-- -- \directlua{dofile "dednat6load.lua"}  % (find-LATEX "dednat6load.lua")





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