Re: 'in' keyword today (was Re: mathlib)

[Coroutines <coroutines@...>]

On Wed, Apr 9, 2014 at 1:22 AM, Dirk Laurie <dirk.laurie@gmail.com> wrote:
> 2014-04-09 6:30 GMT+02:00 Coroutines <coroutines@gmail.com>:
>
>> I think I would suggest both an 'in' and 'from' so this would be possible:
>>
>> local a, b, c in some_table
>> local t_concat, t_insert = concat, insert from table
>
> The proposed 'in' is attractive to those whose programming style
> involves locals with the same name as globals (in _ENV) and
> nothing like it can be done in Lua without duplicating the names.
> Though this is a mere sugar, I would probably use it if available.
> The fact that it does not require another keyword also counts
> in its favour.
>
> The proposed 'from', on the other hand, is not too hard to imitate
> in pure Lua.
>
>     local t_concat, t_insert = from(table,"concat,insert")

I do like that -- I was suggesting both keywords but it read poorly
even while typing it.  The only issue then is that from() would have
to create a temporary table to then unpack() on return -- if this were
done by upstream it could be in C and trustworthy..

On the other hand if it winds up just being used for local
declarations at the head of files then performance isn't a concern and
it could be written in pure Lua just fine.

> I don't think the impact is dramatic enough to justify another keyword.
>
>> I'm thinking about making it of the form:  table.import(into, from,
>> options{}, ...)
>
> There is something not too dissimilar in Penlight -- maybe Steve can
> chip in here.
>

I kinda shy away from Penlight because it gives me that "big,
monolithic library" impression -- is it very interdependent or do you
have a lot of granularity to pull in just what you need.  I wouldn't
mind installing it -- the distribution size doesn't bother me, it's
keeping what I don't use out of memory that concerns me.  There are
places where I have to be pretty light on memory -- my NAS mostly.