Re: Detailed On-line Explanation of What's New in 5.1?

["Alex Davies" <alex.mania@...>]

Veli-Pekka Tätilä wrote:
> In particular, the new var-arg syntax baffles me even having read the 
> vararg second class citizen article in the Lua wiki. Why the change to 
> make vararg processing more cumbersome?
It's faster. A lot of vararg functions can be written now without any 
creating any objects, where as before trying to write, for example, assert 
in Lua would have been very slow. Now it just looks like this:

function assert(val, ...)
 if not val then
   error(... or "assertion failed")
 end
 return val, ...
end

Quite a bit nicer, neater and a lot faster then the old way where the last 
line would look like:
 return cond, unpack(arg)

And where you need to iterate over the arguments, or address them via 
number, the creation of a table is incredibly simple:
 local arg = {...}

> I do liek the fact that the list has a name like ... now, and you can even 
> pass such lists to modules. Which reminds me, can I pass extra args to 
> modules when requiring them, like i can in Perl's use operator? How does 
> the module magiclly get its name as the first element of ... anyway?

According to http://www.lua.org/manual/5.1/manual.html#pdf-require require 
passes modname to the loader, and does not take any additional arguments. 
Surprised actually, thought it would pass them on.

- Alex