Lua packages

0.index.lua

_G.createContext()

local a = require('complex')
print( a.add(5, 6) )

1.global.lua

-- GLOBAL CHANGES --

-- make requires return the object --
_require = _G.require
_G.require = function (name)
  local original = _G[name]
  _require(name)
  local package = _G[name]
  _G[name] = original
  return package
end


-- creating contexts for files --
_G.createContext = function ()
  _G.createPackageContext(nil)
end

_G.createPackageContext = function (packageName)
  local exports = {};
  setmetatable(exports, {__index = _G})
  if (packageName) then
    _G[packageName] = exports;
  end
  setfenv(2, exports)
end

2.complex.lua

_G.createPackageContext(...)

function add(a, b)
  print('calculating')
  return a + b
end

3.output.txt

$ lua -l global index.lua
calculating
11

This allows you to require modules and store the result in a variable. It also provides helper methods that set the file context properly so that you don't create globals all over the place.