Re: [ 5.4 ] Sequence Iteration - Knowing when to Stop?

[Dirk Laurie <dirk.laurie@...>]

What happened when it reached the end of the list?

2018-05-29 21:06 GMT+02:00 Soni "They/Them" L. <fakedme@gmail.com>:
>
>
> On 2018-05-29 03:58 PM, Dirk Laurie wrote:
>>
>> 2018-05-29 20:32 GMT+02:00 Russell Haley <russ.haley@gmail.com>:
>>>
>>>
>>> On Tue, May 29, 2018 at 9:53 AM, Roberto Ierusalimschy
>>> <roberto@inf.puc-rio.br> wrote:
>>>>>
>>>>>       Just musings, but... I hope they get in, and I hope that
>>>>> `lua_keyin`
>>>>> as well as the potential hypothetical `lua_keyvalue` include versions
>>>>> that
>>>>> get integers and fields for number / string arguments directly (as well
>>>>> as
>>>>> their raw version), making for a full suite that allows maximum
>>>>> performance
>>>>> and mimics the current Lua C API structure:
>>>>>
>>>>>       [...]
>>>>
>>>> We have decided that, at least for 5.4, we are not going on with
>>>> the nils-in-table proposal. Although we really like the idea, the
>>>> compatibility problems seem too big. As this message evidentiates again,
>>>> the language would need a lot of extra stuff (metamethods, API calls,
>>>> etc.), even when the option is off.
>>>>
>>>> -- Roberto
>>>>
>>> : - (
>>>
>>> That's too bad.  The behavior of holes in tables was a huge block for me
>>> when I started using Lua (and is still a pain in the ass IMO). I think
>>> allowing nil in tables removes a hole in the language (pun intended) and
>>> makes tables jmore friendly for newcomers and more practical for using as
>>> a
>>> sequence. Are we going to have to wait another 4 years for you to tease
>>> us
>>> with the possibility again?
>>>
>>> This is very disappointing news. (To be clear, the news disappoints me,
>>> not
>>> the people or the language. No flaming necessary).
>>
>> Nils in tables will be very counterintuitive for people who for
>> several years have used mainly Lua. (It may be OK for some people
>> still used to what their previous language did.)
>>
>> Some years ago, I had this bright idea. Self-initializing tables. The
>> first time you access tbl[i], the __index metamethod would kick in and
>> construct the object. Items you never access need never be
>> initialized. Brilliant.
>>
>> Until a table in which I had initialized everything was used in `for
>> k,v in ipairs(tbl) do`. Work out what happened. It was painful.
>>
>
> It initialized everything, in order, one by one, using a very slow integer
> factorization algorithm?
>
> Or was this pre-Lua 5.3?
>
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