We're considering a modification to the version of Lua embedded in our game engine that would allow for this construct (which is currently a syntax error in Lua):
Under the present language rules, myInstance:instanceMethod is an error (as I understand it) because the colon notation is only valid in the context of function calls and function declarations, but is not valid in the context of specifying a function value. Currently, we can accomplish this goal by instead making the statement "CallbackManager.postMyCallback(function () myInstance:instanceMethod() end)", but that seems to be a great deal more typing than should be necessary.
I picked the IRC channel's collective brain on this issue, and we discussed the performance impact aspects of this design. But I also wanted to ask the mailing-list community: is there any syntactical reason that I would want to avoid allowing myInstance:instanceMethod to become a valid construct outside of a function declaration (as, for instance, a shorthand alias for constructing the closure as I described)? I'm nervous about getting halfway down the road of trying out this modification and then running headlong into a language ambiguity.
Thank you for the input!