Hi José
there are occasions like when doing ... |> Enum.map(&first) |> ... where
pattern matching does not apply, and .. |> Enum.map(&elem(&1,0)) |> ... is
much less readable.
It was regarding these cases that I thought about tuple accessors.
Mário Guimarães
sexta-feira, 5 de Abril de 2019 às 12:42:11 UTC+1, José Valim escreveu:
>
> But perhaps, the most important, is that generally you should be pattern
> matching on tuples.
>
> Most of the times, you know exactly the size of the tuple you are working
> with, and pattern matching on it is more intention revealing.
>
> If you have large tuples and the size may change, then sure, pattern
> matching is not a good idea, but then the Record module becomes handy.
> Record allows you to work with tuples and give also them names, and the
> names are a better API than relying on indexes.
>
> *José Valim*
> www.plataformatec.com.br
> Skype: jv.ptec
> Founder and Director of R&D
>
>
> On Fri, Apr 5, 2019 at 1:13 PM Arjan Scherpenisse <scherp...@gmail.com
> <javascript:>> wrote:
>
>> If you really want this, you could metaprogram it yourself ;-)
>>
>> defmodule TupleAccess do
>> @names ~w(first second third fourth fifth sixth seventh eight ninth
>> tenth)a
>>
>> for {name, index} <- Enum.with_index(@names) do
>> def unquote(name)(tuple) do
>> elem(tuple, unquote(index))
>> end
>> end
>> end
>>
>> iex(5)> import TupleAccess
>> TupleAccess
>> iex(6)> first({:a})
>> :a
>> iex(7)> first({:a, :b})
>> :a
>> iex(8)> second({:a, :b})
>> :b
>>
>>
>> On Friday, April 5, 2019 at 1:05:35 PM UTC+2, Louis Pilfold wrote:
>>>
>>> Hey
>>>
>>> We have elem/2, which is quite clear and more concise.
>>>
>>> We don't need specific functions for each index because we are not
>>> limited by a static type system and so the index does not need to be known
>>> at compile time.
>>>
>>> Cheers,
>>> Louis
>>>
>>> On Fri, 5 Apr 2019, 11:29 Mário Guimarães, <mario.lui...@gmail.com>
>>> wrote:
>>>
>>>> Hello,
>>>>
>>>> any reason why there are no easy readable idioms like
>>>>
>>>> first, snd, third, ..., tenth (I guess is enough)
>>>>
>>>> to access tuples?
>>>>
>>>> Thanks
>>>>
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