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On Mar 19, 2013, at 9:23 PM, William Sumner <> wrote:

> Lua's behavior of silently returning nil for undefined variables can lead to bugs that propagate undetected. Has thought been given to changing this in a major version update, or are there reasons for retaining this behavior? I'm aware of strict.lua, but it only provides safety for global/module scope.

Something like this perhaps?

  local error = error
  local print = print
  local _ENV = setmetatable( {}, { __index = function( self, aKey ) error( ( 'Undefined %q' ):format( aKey ) ) end } )

  foo = 1
  print( 1, foo )
  print( 2, bar )