Re: Features you would like to see

[David Given <dg@...>]

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Patrick Donnelly wrote:
[...]
> What features would you like to see added?

I'd like a goto.

The whole goto-considered-harmful myth has done the world a vast disservice.
goto is *entirely* the right construct for dealing with certain software
problems: for example, state machines. (And, in fact, Dijkstra was completely
up front about this in his original paper.) They're also very handy for doing
things like cleanup on error:

	if not function1() then
		goto exit
	end
	if not function2() then
		goto cleanup1_and_exit
	end
	if not function3() then
		goto cleanup2_and_exit
	end
	return success

	cleanup3()
cleanup2_and_exit:
	cleanup2()
cleanup1_and_exit:
	cleanup1()
	return failure

The alternative approach is to use lots of nested if statements, which can
quickly get out of control if your logic is at all complicated --- and if you
need an exit strategy from within, say, a loop, you're basically stuffed. You
have to either duplicate code or use flag variables.

(They can also be trivially used for 'continue' and multi-level 'break'.)

...and while I'm whinging, it would also be nice to have some
try/catch/finally/throw syntactic sugar around pcall and error. I know it's
Not The Lua Way to provide high-level functionality like that, but exceptions
are so useful, and doing them yourself with pcall is so wordy, that I reckon
it's worth doing in this case.

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