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diff --git a/test/lua/compat_env.lua b/test/lua/compat_env.lua
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+++ b/test/lua/compat_env.lua
@@ -0,0 +1,391 @@
+--[[
+
+  compat_env v$(_VERSION) - Lua 5.1/5.2 environment compatibility functions
+
+SYNOPSIS
+
+  -- Get load/loadfile compatibility functions only if using 5.1.
+  local CL = pcall(load, '') and _G or require 'compat_env'
+  local load     = CL.load
+  local loadfile = CL.loadfile
+  
+  -- The following now works in both Lua 5.1 and 5.2:
+  assert(load('return 2*pi', nil, 't', {pi=math.pi}))()
+  assert(loadfile('ex.lua', 't', {print=print}))()
+  
+  -- Get getfenv/setfenv compatibility functions only if using 5.2.
+  local getfenv = _G.getfenv or require 'compat_env'.getfenv
+  local setfenv = _G.setfenv or require 'compat_env'.setfenv
+  local function f() return x end
+  setfenv(f, {x=2})
+  print(x, getfenv(f).x) --> 2, 2
+
+DESCRIPTION
+
+  This module provides Lua 5.1/5.2 environment related compatibility functions.
+  This includes implementations of Lua 5.2 style `load` and `loadfile`
+  for use in Lua 5.1.  It also includes Lua 5.1 style `getfenv` and `setfenv`
+  for use in Lua 5.2.
+ 
+API
+
+  local CL = require 'compat_env'
+  
+  CL.load (ld [, source [, mode [, env] ] ]) --> f [, err]
+
+    This behaves the same as the Lua 5.2 `load` in both
+    Lua 5.1 and 5.2.
+    http://www.lua.org/manual/5.2/manual.html#pdf-load
+    
+  CL.loadfile ([filename [, mode [, env] ] ]) --> f [, err]
+  
+    This behaves the same as the Lua 5.2 `loadfile` in both
+    Lua 5.1 and 5.2.
+    http://www.lua.org/manual/5.2/manual.html#pdf-loadfile
+    
+  CL.getfenv ([f]) --> t
+
+    This is identical to the Lua 5.1 `getfenv` in Lua 5.1.
+    This behaves similar to the Lua 5.1 `getfenv` in Lua 5.2.
+    When a global environment is to be returned, or when `f` is a
+    C function, this returns `_G`  since Lua 5.2 doesn't have
+    (thread) global and C function environments.  This will also
+    return `_G` if the Lua function `f` lacks an `_ENV`
+    upvalue, but it will raise an error if uncertain due to lack of
+    debug info.  It is not normally considered good design to use
+    this function; when possible, use `load` or `loadfile` instead.
+    http://www.lua.org/manual/5.1/manual.html#pdf-getfenv
+    
+  CL.setfenv (f, t)
+  
+    This is identical to the Lua 5.1 `setfenv` in Lua 5.1.
+    This behaves similar to the Lua 5.1 `setfenv` in Lua 5.2.
+    This will do nothing if `f` is a Lua function that
+    lacks an `_ENV` upvalue, but it will raise an error if uncertain
+    due to lack of debug info.  See also Design Notes below.
+    It is not normally considered good design to use
+    this function; when possible, use `load` or `loadfile` instead.
+    http://www.lua.org/manual/5.1/manual.html#pdf-setfenv
+    
+DESIGN NOTES
+
+  This module intends to provide robust and fairly complete reimplementations
+  of the environment related Lua 5.1 and Lua 5.2 functions.
+  No effort is made, however, to simulate rare or difficult to simulate features,
+  such as thread environments, although this is liable to change in the future.
+  Such 5.1 capabilities are discouraged and ideally
+  removed from 5.1 code, thereby allowing your code to work in both 5.1 and 5.2.
+  
+  In Lua 5.2, a `setfenv(f, {})`, where `f` lacks any upvalues, will be silently
+  ignored since there is no `_ENV` in this function to write to, and the
+  environment will have no effect inside the function anyway.  However,
+  this does mean that `getfenv(setfenv(f, t))` does not necessarily equal `t`,
+  which is incompatible with 5.1 code (a possible workaround would be [1]).
+  If `setfenv(f, {})` has an upvalue but no debug info, then this will raise
+  an error to prevent inadvertently executing potentially untrusted code in the
+  global environment.
+  
+  It is not normally considered good design to use `setfenv` and `getfenv`
+  (one reason they were removed in 5.2).  When possible, consider replacing
+  these with `load` or `loadfile`, which are more restrictive and have native
+  implementations in 5.2.
+  
+  This module might be merged into a more general Lua 5.1/5.2 compatibility
+  library (e.g. a full reimplementation of Lua 5.2 `_G`).  However,
+  `load/loadfile/getfenv/setfenv` perhaps are among the more cumbersome
+  functions not to have.
+
+INSTALLATION
+
+  Download compat_env.lua:
+  
+    wget https://raw.github.com/gist/1654007/compat_env.lua
+
+  Copy compat_env.lua into your LUA_PATH.
+  
+  Alternately, unpack, test, and install into LuaRocks:
+  
+     wget https://raw.github.com/gist/1422205/sourceunpack.lua
+     lua sourceunpack.lua compat_env.lua
+     (cd out && luarocks make)
+
+Related work
+
+  http://lua-users.org/wiki/LuaVersionCompatibility
+  https://github.com/stevedonovan/Penlight/blob/master/lua/pl/utils.lua
+    - penlight implementations of getfenv/setfenv
+  http://lua-users.org/lists/lua-l/2010-06/msg00313.html
+    - initial getfenv/setfenv implementation
+    
+References
+
+  [1] http://lua-users.org/lists/lua-l/2010-06/msg00315.html
+
+Copyright
+
+(c) 2012 David Manura.  Licensed under the same terms as Lua 5.1/5.2 (MIT license).
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+
+--]]---------------------------------------------------------------------
+
+local M = {_TYPE='module', _NAME='compat_env', _VERSION='0.2.20120124'}
+
+local function check_chunk_type(s, mode)
+  local nmode = mode or 'bt' 
+  local is_binary = s and #s > 0 and s:byte(1) == 27
+  if is_binary and not nmode:match'b' then
+    return nil, ("attempt to load a binary chunk (mode is '%s')"):format(mode)
+  elseif not is_binary and not nmode:match't' then
+    return nil, ("attempt to load a text chunk (mode is '%s')"):format(mode)
+  end
+  return true
+end
+
+local IS_52_LOAD = pcall(load, '')
+if IS_52_LOAD then
+  M.load     = _G.load
+  M.loadfile = _G.loadfile
+else
+  -- 5.2 style `load` implemented in 5.1
+  function M.load(ld, source, mode, env)
+    local f
+    if type(ld) == 'string' then
+      local s = ld
+      local ok, err = check_chunk_type(s, mode); if not ok then return ok, err end
+      local err; f, err = loadstring(s, source); if not f then return f, err end
+    elseif type(ld) == 'function' then
+      local ld2 = ld
+      if (mode or 'bt') ~= 'bt' then
+        local first = ld()
+        local ok, err = check_chunk_type(first, mode); if not ok then return ok, err end
+        ld2 = function()
+          if first then
+            local chunk=first; first=nil; return chunk
+          else return ld() end
+        end
+      end
+      local err; f, err = load(ld2, source); if not f then return f, err end
+    else
+      error(("bad argument #1 to 'load' (function expected, got %s)"):format(type(ld)), 2)
+    end
+    if env then setfenv(f, env) end
+    return f
+  end
+
+  -- 5.2 style `loadfile` implemented in 5.1
+  function M.loadfile(filename, mode, env)
+    if (mode or 'bt') ~= 'bt' then
+      local ioerr
+      local fh, err = io.open(filename, 'rb'); if not fh then return fh, err end
+      local function ld() local chunk; chunk,ioerr = fh:read(4096); return chunk end
+      local f, err = M.load(ld, filename and '@'..filename, mode, env)
+      fh:close()
+      if not f then return f, err end
+      if ioerr then return nil, ioerr end
+      return f
+    else
+      local f, err = loadfile(filename); if not f then return f, err end
+      if env then setfenv(f, env) end
+      return f
+    end
+  end
+end
+
+if _G.setfenv then -- Lua 5.1
+  M.setfenv = _G.setfenv
+  M.getfenv = _G.getfenv
+else -- >= Lua 5.2
+  -- helper function for `getfenv`/`setfenv`
+  local function envlookup(f)
+    local name, val
+    local up = 0
+    local unknown
+    repeat
+      up=up+1; name, val = debug.getupvalue(f, up)
+      if name == '' then unknown = true end
+    until name == '_ENV' or name == nil
+    if name ~= '_ENV' then
+      up = nil
+      if unknown then error("upvalues not readable in Lua 5.2 when debug info missing", 3) end
+    end
+    return (name == '_ENV') and up, val, unknown
+  end
+
+  -- helper function for `getfenv`/`setfenv`
+  local function envhelper(f, name)
+    if type(f) == 'number' then
+      if f < 0 then
+        error(("bad argument #1 to '%s' (level must be non-negative)"):format(name), 3)
+      elseif f < 1 then
+        error("thread environments unsupported in Lua 5.2", 3) --[*]
+      end
+      f = debug.getinfo(f+2, 'f').func
+    elseif type(f) ~= 'function' then
+      error(("bad argument #1 to '%s' (number expected, got %s)"):format(type(name, f)), 2)
+    end
+    return f
+  end
+  -- [*] might simulate with table keyed by coroutine.running()
+  
+  -- 5.1 style `setfenv` implemented in 5.2
+  function M.setfenv(f, t)
+    local f = envhelper(f, 'setfenv')
+    local up, val, unknown = envlookup(f)
+    if up then
+      debug.upvaluejoin(f, up, function() return up end, 1) -- unique upvalue [*]
+      debug.setupvalue(f, up, t)
+    else
+      local what = debug.getinfo(f, 'S').what
+      if what ~= 'Lua' and what ~= 'main' then -- not Lua func
+        error("'setfenv' cannot change environment of given object", 2)
+      end -- else ignore no _ENV upvalue (warning: incompatible with 5.1)
+    end
+    -- added in https://gist.github.com/2255007
+    return f
+  end
+  -- [*] http://lua-users.org/lists/lua-l/2010-06/msg00313.html
+
+  -- 5.1 style `getfenv` implemented in 5.2
+  function M.getfenv(f)
+    if f == 0 or f == nil then return _G end -- simulated behavior
+    local f = envhelper(f, 'setfenv')
+    local up, val = envlookup(f)
+    if not up then return _G end -- simulated behavior [**]
+    return val
+  end
+  -- [**] possible reasons: no _ENV upvalue, C function
+end
+
+
+return M
+
+--[[ FILE rockspec.in
+
+package = 'compat_env'
+version = '$(_VERSION)-1'
+source = {
+  url = 'https://raw.github.com/gist/1654007/$(GITID)/compat_env.lua',
+  --url = 'https://raw.github.com/gist/1654007/compat_env.lua', -- latest raw
+  --url = 'https://gist.github.com/gists/1654007/download',
+  md5 = '$(MD5)'
+}
+description = {
+  summary = 'Lua 5.1/5.2 environment compatibility functions',
+  detailed = [=[
+    Provides Lua 5.1/5.2 environment related compatibility functions.
+    This includes implementations of Lua 5.2 style `load` and `loadfile`
+    for use in Lua 5.1.  It also includes Lua 5.1 style `getfenv` and `setfenv`
+    for use in Lua 5.2.
+  ]=],
+  license = 'MIT/X11',
+  homepage = 'https://gist.github.com/1654007',
+  maintainer = 'David Manura'
+}
+dependencies = {}  -- Lua 5.1 or 5.2
+build = {
+  type = 'builtin',
+  modules = {
+    ['compat_env'] = 'compat_env.lua'
+  }
+}
+
+--]]---------------------------------------------------------------------
+
+--[[ FILE test.lua
+
+-- test.lua - test suite for compat_env module.
+
+local CL = require 'compat_env'
+local load     = CL.load
+local loadfile = CL.loadfile
+local setfenv  = CL.setfenv
+local getfenv  = CL.getfenv
+
+local function checkeq(a, b, e)
+  if a ~= b then error(
+    'not equal ['..tostring(a)..'] ['..tostring(b)..'] ['..tostring(e)..']')
+  end
+end
+local function checkerr(pat, ok, err)
+  assert(not ok, 'checkerr')
+  assert(type(err) == 'string' and err:match(pat), err)
+end
+
+-- test `load`
+checkeq(load('return 2')(), 2)
+checkerr('expected near', load'return 2 2')
+checkerr('text chunk', load('return 2', nil, 'b'))
+checkerr('text chunk', load('', nil, 'b'))
+checkerr('binary chunk', load('\027', nil, 't'))
+checkeq(load('return 2*x',nil,'bt',{x=5})(), 10)
+checkeq(debug.getinfo(load('')).source, '')
+checkeq(debug.getinfo(load('', 'foo')).source, 'foo')
+
+-- test `loadfile`
+local fh = assert(io.open('tmp.lua', 'wb'))
+fh:write('return (...) or x')
+fh:close()
+checkeq(loadfile('tmp.lua')(2), 2)
+checkeq(loadfile('tmp.lua', 't')(2), 2)
+checkerr('text chunk', loadfile('tmp.lua', 'b'))
+checkeq(loadfile('tmp.lua', nil, {x=3})(), 3)
+checkeq(debug.getinfo(loadfile('tmp.lua')).source, '@tmp.lua')
+checkeq(debug.getinfo(loadfile('tmp.lua', 't', {})).source, '@tmp.lua')
+os.remove'tmp.lua'
+
+-- test `setfenv`/`getfenv`
+x = 5
+local a,b=true; local function f(c) if a then return x,b,c end end
+setfenv(f, {x=3})
+checkeq(f(), 3)
+checkeq(getfenv(f).x, 3)
+checkerr('cannot change', pcall(setfenv, string.len, {})) -- C function
+checkeq(getfenv(string.len), _G) -- C function
+local function g()
+  setfenv(1, {x=4})
+  checkeq(getfenv(1).x, 4)
+  return x
+end
+checkeq(g(), 4) -- numeric level
+if _G._VERSION ~= 'Lua 5.1' then
+  checkerr('unsupported', pcall(setfenv, 0, {}))
+end
+checkeq(getfenv(0), _G)
+checkeq(getfenv(), _G) -- no arg
+checkeq(x, 5) -- main unaltered
+setfenv(function()end, {}) -- no upvalues, ignore
+checkeq(getfenv(function()end), _G) -- no upvaluse
+if _G._VERSION ~= 'Lua 5.1' then
+  checkeq(getfenv(setfenv(function()end, {})), _G) -- warning: incompatible with 5.1
+end
+x = nil
+
+print 'OK'
+
+--]]---------------------------------------------------------------------
+
+--[[ FILE CHANGES.txt
+0.2.20120124
+  Renamed module to compat_env (from compat_load)
+  Add getfenv/setfenv functions
+
+0.1.20120121
+  Initial public release
+--]]