Re: hpairs?

[Emmanuel Oga <emmanueloga@...>]

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EmmanuelOga.com - Software Developer



On Sun, Jan 2, 2011 at 8:25 PM, Axel Kittenberger <axkibe@gmail.com> wrote:
> Try it with {1, 2, nil, nil, 5}.
>
> will 5 turn up in the not ipairs part?

It won't, but since ipairs stops iterating when it finds the first
nil, the at_ipairs function will stop there too:

a = arrayTable{1, 2, nil, nil, 5}

for i, v in at_ipairs(a) do
  print(v) --> prints 1 \n 2
end

for i, v in at_pairs(a) do
  print(i, v)  --> does not print anything, all keys are integers
end

print(a[1]) --> 1
print(a[2]) --> 2
print(a[3]) --> nil
print(a[4]) --> nil
print(a[5]) --> 5

>
> On Mon, Jan 3, 2011 at 12:00 AM, Emmanuel Oga <emmanueloga@gmail.com> wrote:
>> I came up with this experiment involving __index and __newindex to
>> segregate a table in its array part and non-array part:
>>
>> https://gist.github.com/762890
>>
>> Caveats:
>>
>> It requires an special constructor to create the table:
>>
>>  t = arrayTable{1, 2, a = 1}
>>  t[1.5]=1.5
>>
>> It requires special iterators replacing both ipairs and pairs:
>>
>>  for k,v in at_ipairs(t) do print(k, v) end
>>  for k,v in at_pairs(t) do print(k, v) end
>>
>> Alternatively you can use the indexes to the real table/array provided
>> in the table
>>
>>  for k,v in ipairs(t.___array) do print(k, v) end
>>  for k,v in pairs(t.___table) do print(k, v) end
>>
>> Which I believe is even more ugly than using the iterators above.
>>
>> I tried to override __len on the metatable but apparently that does
>> not work in lua 5.1 (I read somewhere __len will be overridable for
>> tables/strings in 5.2?)
>>
>> --------------------------------------------------------------
>> EmmanuelOga.com - Software Developer
>>
>>
>
>