with

function with(scope)
  local cEnv = {}
  local oEnv = getfenv(2)
  local cEnvMT = {}
  local outT = {}
  local outMT = {}

  outMT.__index = function(t,k)
    return oEnv[k]
  end

  outMT.__newindex = function(t,k,v)
    oEnv[k]=v
  end

  outMT.__call = function(...)
    setfenv(2,oEnv)
    oEnv = nil
  end
  setmetatable(outT,outMT)

  cEnvMT.__index = function(t,k)
    if k == "out" then
      return outT
    else
      return scope[k] or outT[k]
    end
  end

  cEnvMT.__newindex = function(t,k,v)
    scope[k]=v
  end

  setmetatable(cEnv,cEnvMT)
  setfenv(2,cEnv)
end