split compat53 Lua module into separate modules that do/don't modify the global env

1 files changed, 37 insertions, 0 deletions

diff --git a/compat53/module.lua b/compat53/module.lua
new file mode 100644
index 0000000..f6fd1f7
--- /dev/null
+++ b/compat53/module.lua
@@ -0,0 +1,37 @@
+local _G, _VERSION, debug, error, require, setfenv, setmetatable =
+      _G, _VERSION, debug, error, require, setfenv, setmetatable
+local lua_version = _VERSION:sub(-3)
+local M = require("compat53.base")
+
+local function findmain()
+   local i = 3
+   local info = debug.getinfo(i, "fS")
+   while info do
+      if info.what == "main" then
+         return info.func
+      end
+      i = i + 1
+      info = debug.getinfo(i, "fS")
+   end
+end
+
+local main = findmain()
+if not main then
+   error("must require 'compat53.module' from Lua")
+end
+local env = setmetatable({}, {
+   __index = M,
+   __newindex = _G,
+})
+if lua_version == "5.1" then
+   setfenv(main, env)
+elseif lua_version == "5.2" or lua_version == "5.3" then
+   debug.setupvalue(main, 1, env)
+else
+   error("unsupported Lua version")
+end
+
+-- return false to force reevaluation on next require
+return false
+
+-- vi: set expandtab softtabstop=3 shiftwidth=3 :