Re: [ANN] Lua 5.2.0 (work1) now available

[Renato Maia <maia@...>]

On 14 Jan 2010, at 22:51, Klaus Ripke wrote:
> On Sat, Jan 09, 2010 at 12:52:33PM +0300, Alexander Gladysh wrote:
> > On Sat, Jan 9, 2010 at 12:37, steve donovan <steve.j.donovan@gmail.com 
> > > wrote:
> > > 2010/1/9 Ignacio Burgueño <ignaciob@inconcertcc.com>:
> > > > > 17. Documented behaviour of ipairs() is changed from "iterates  
> > > > > until
> > > > > *first nil*" to "traverses table length elements as defined by  
> > > > > length
> > > > > operator".
> >
> > > This is more consistent, but given how strange #t is when t has a
> > > number of holes, it isn't necessarily more useful.
> >
> > (1) Don't have holes in tables you want to measure with #, that's  
> > all.
>
> That's why this change to rely on #t is completely beyond me.

It might be intended for tables that redefine the meaning of #:

Lua 5.2.0 (work2)  Copyright (C) 1994-2010 Lua.org, PUC-Rio
> m={}
> m.__len = function() return 3 end
> m.__index = function(_, ...) return ... end
> t = setmetatable({}, m)
> for k,v in ipairs(t) do print(k,v) end
1	nil
2	nil
3	nil

As much as I love those metamethods tricks, I must say they seem to me  
more scary than useful when they do not come with their 'raw*'  
counterparts. I remember pretty well how it felt the few times all I  
wanted was a 'rawtostring', so I rather not think how it will feel nor  
the many times I might be hoping for a 'rawipairs' in the future. (or  
a 'rawlen' for that matter)

--
Renato Maia
Computer Scientist
Tecgraf/PUC-Rio
__________________________
http://www.inf.puc-rio.br/~maia/