I'm also in favor of including an `id` function.
On Tue, Jul 2, 2019 at 8:52 AM Bruce Tate <br...@grox.io> wrote:
> Strong +1 from me.
>
> I also think we need default functions for some Enum functions, such as
> filter.
>
> -bt
>
> On Tue, Jul 2, 2019 at 5:54 AM Wiebe-Marten Wijnja <w...@resilia.nl> wrote:
>
>> I would usually be against introducing concepts to the core's standard
>> library that can be readily and easily expressed in user code.
>> However, in this case I think there are two strong arguments for
>> including the identity function in the standard library:
>>
>> 1. It is a great tool to help people new to functional programming with
>> their understanding.
>> 2. It is a lot more clear in its purpose than `&(&1)` because it has a
>> name. (c.f. earlier operators vs named functions discussions).
>>
>> ~Marten/Qqwy
>>
>> On Tuesday, July 2, 2019 at 11:23:47 AM UTC+2, Alexey Nikitin wrote:
>>>
>>> Like Haskell's `id` or Clojure's `identity` or Ruby's `itself`
>>>
>>> It can be very useful sometimes. Instead of writing ugly `&(&1)` it
>>> would much more attractive to write `&identity/1` or `&id\1`
>>> Moreover this function is already used as a default argument for some
>>> higher-order function. For example `Enum.group_by(enumerable, key_fun,
>>> value_fun \\ fn x -> x end)`
>>>
>>> Here are some examples
>>>
>>> ```
>>> #=> [1, 2, 3, true, 1234]
>>>
>>> 'abcdaabccc' |> Enum.sort |> Enum.chunk_by(&identity/1)
>>> #=> ['aaa', 'bb', 'cccc', 'd']
>>>
>>> [1, 1, 2, 3, 3, 1, 1, 5, 5] |> Enum.chunk_by(&identity/1) |>
>>> Enum.map(&hd/1)
>>> #=> [1, 2, 3, 1, 5]
>>>
>>> Enum.group_by('abracadabra', &identity/1)
>>> #=> %{97 => 'aaaaa', 98 => 'bb', 99 => 'c', 100 => 'd', 114 => 'rr'}
>>>
>>> Enum.map([1, 2, 3, 4], &identity/1)
>>> #=> [1, 2, 3, 4]
>>> [1,2,3,nil, true, false, 1234] |> Enum.filter(&identity/1)
>>> ```
>>>
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> Bruce Tate
> CEO
>
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--
Chris
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