Re: Lua design : why no lists ?

[Asko Kauppi <asko.kauppi@...>]

I like the open attitude with which you write, coming from the Python 
world.. :)

To cover the tuple issue first, yes, that has been discussed -quite 
intensively in fact- recently on this list.  No clear solution, yet, 
there are pros and cons.  I guess we're just waiting, what will be in 
5.1, am I right?

On dedicated lists, my first reaction was "why"?  This may be an issue 
where you have to delearn something. Personally, I couldn't come up 
with a single case where I'd needed lists with Lua.  And even if I did, 
a case where the runtime cost would have called for optimization.

There are, as you know, 'table.insert' and 'table.remove'.  These can 
be used either as a stack or as a list. You can close your eyes from 
the fact that they're really tables. Or rename to 'list.insert' and 
'list.remove' if you like? :P

If you have a good case, could you share that with us?  Something, 
where having a dedicated list object would really boost the performance 
of the application?  As Aaron pointed out, you'd be able to easily 
build your own mechanics using the building blocks of Lua. I would not, 
however, start making a list type.

-ak


13.9.2004 kello 22:09, Philippe Fremy kirjoitti:

> 	Hi,
>
> I am quite new to lua but I have a python background. I think lua is 
> great
> because it is _very_ easy to embed, and is quite a powerful language, 
> by
> its simplicity. I love that class as table thing for example.
>
> However, there are two things that I find strange:
> 1. the absence of list
> 2. the pack/unpack thing
>
> The absence of list surprise me. A list is quite a common need and
> implementing the current list on top of tables is not as convenient 
> and as
> simple as a real list. A list is quite simple, and I believe, easier to
> optimise than a full table. Why not provide one ? I find the hacks 
> around
> table to make it emulate list behaviour not very elegant, for something
> that common.
>
> The second thing which surprise me is the pack/unpack thing. In lua, 
> you
> have no object to represent the (1,2). You can pack them and unpack 
> them
> but it is difficult to get a hand on them. When a function return 
> a,b,c ,
> you can either store each of them but maniuplating the result without
> storing a,b,c into 3 variables is not very practicle. You need to
> pack/unpack them before doing anything. I find this quite suprising 
> given
> the simplicity and the power of the rest of the language.
>
> I like the two together. With a proper list implementation, it would be
> easier to manipulate packed data.
>
> I am curious about the design decision behind this. If somebody where 
> to
> implement list in lua, would it be rejected ?
>
> 	regards,
>
> 	Philippe
>
>
> --
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