Re: Next Version of Lua?

[Olivier Hamel <evilpineapple@...>]

steve donovan wrote:
> On Wed, Jun 10, 2009 at 12:02 PM, Olivier Hamel<evilpineapple@cox.net> wrote:
>   
> It does this already, last time I checked (-3 secs ago) Are you
> thinking of hex string literals?
>   
Oops, yah. My mistake, sorry!

> As operators? I think most of us would live with a set of 'blessed'
> functions to do this.
That could work, I just think it'd be/feel more elegant/neater to make 
them ops, then perhaps we can meta-overload them as well... ?
> The thing, we're used to the rule that multiple args only get expanded
> at the end of a table ctor. Maybe an explicit 'explode' function, but
> keeping the default behaviour? Changes like this can break lots of
> code.
>   
That will not be an issue, Roberto has already publicly confirmed he 
will be break everyone's code anyways:
"Lua 5.2 is allowed to make design changes that break full 
compatibility." :p

But I do get your point, but the problem is that such an explode 
function would also be under the restrictions as the original function 
unless it were hacked deep into Lua, something I doubt would be popular 
with Roberto + others (including me). Perhaps some sort of lexer marker 
instead?
> OK, so like __setindex if the key is nil, but works even otherwise.
> You can then override '=' for keys basically.  But there are tricks
> you can use already to get this effect, e.g. the key is actually
> called '_a' but use __setindex so that 'A.a = 2' updates _a, etc.
>   
No, no, I mean, if it's NOT nil then the metamethod get's called, it 
would allow you to create enforced single-assignment lists for example, 
or prevent overriding of a meta-method in the metatable. To prevent a 
new method from being inserted into the host table would require a 
__setindex sort of scheme, though with __setindex you could check for 
the current value of the key to check if it were nil. So __setindex 
solves both aspects! :)
(Correct me if I'm wrong, but __setindex doesn't sound like any vanilla 
meta-method I know of. Am I wrong?)

Olivier Hamel