Re: [ANN] Lua 5.2.0 (work3) now available

[Sean Conner <sean@...>]

It was thus said that the Great Petite Abeille once stated:
> 
> On May 19, 2010, at 8:59 AM, David Kastrup wrote:
> 
> > If both do exactly the same, the logical thing to keep would be ipairs,
> > not the numeric loop.  Simplifies the language.
> 
> FWIW, I would second that. Drop the numeric loop. And keep ipairs
> alongside the generic for statement.
> 
> Also, while we are at it, drop the while and repeat statement as well. How
> many loopy [sic] constructs does a language need?

  They're there for convenience.  Technically, all you need is a conditional
and a way of diverting flow control---basically, if and goto---and from
there you can build up all looping constructs:

	for i = 1 , 100 do		  i = 1
		...			X:
	end				  ...
					  i = i + 1
				          if i <= 100 then goto X end

	----------------------------------------------

	while morwork do		X:
		...			  if not morework then goto Y end
	end				  ...
					  goto X
					Y:

	-------------------------------------------------

	if foo then do			if not foo then goto X end
		...				...
	end				X:

	----------------------------------------------------

	if foo then do			if not foo then goto X end
		...				...
	else					goto Y
		...			X:
	end					...
					Y:

	----------------------------------------------------

	repeat				X:
		...				...
	until done			if not done then goto X end

  and so on.  Even C has the little used do while() construct.  The "loopy"
constructs are there as a means to express intent.  I hope from the example
above that using "if ... goto" hides the intent and makes it harder to
reason about the code.

  -spc (Just be thankful we don't have Common Lisp's LOOP or even
	INTERCAL's COMEFROM ... )