:) all good.
I do think that both & &1 and fn x -> x end and & &1 are both harder to
scan than &identity/1 as it's almost always better to name a concept for a
beginner (or most anyone, for that matter). In my classes we often write an
identity function as an intermediate teaching step because I can name the
concept. There's less to grok at once.
But no big deal... if we're closing this I will respect your decision.
José, what would you say to have the identity function as a default to
things like Enum.filter and Enum.group_by? Some of the other Enumerable
functions have defaults, such as sort. There's no breaking change and it
obviates the need for the identity function in quite a few places.
Examples: a word counter, where the words might be nil:
words
|> Enum.filter
|> Enum.group_by
|> Map.new(fn {x, y} -> {x, length(y)} end)
Solves the problem of identity for some of the important use cases; no
breaks of backward compatibility; discoverable through existing docs.
-bt
On Fri, Jul 12, 2019 at 1:21 PM José Valim <jose.va...@plataformatec.com.br>
wrote:
> If the goal is teaching, then I think "fn x -> x end" beats both
> "&identify/1" and "& &1" in terms of clarity, as identity itself is still a
> concept that needs to be explained.
>
>
> *José Valim*
> www.plataformatec.com.br
> Skype: jv.ptec
> Founder and Director of R&D
>
>
> On Fri, Jul 12, 2019 at 7:18 PM Bruce Tate <br...@grox.io> wrote:
>
>> > Why should we add this to Elixir core, instead of "extending" with
>> module?
>>
>> I have been a big proponent of this for a long time because just about
>> every code base uses the identity function and it's a barrier to those who
>> would learn Elixir.
>>
>> Rather than import or call &FP.identity/1, most would just continue to
>> use something like & &1, and that's generally tough on beginners.
>>
>> -bt
>>
>> On Fri, Jul 12, 2019 at 12:59 PM Chulki Lee <chulki....@gmail.com> wrote:
>>
>>> I'm happy to see Elixir adopting FP concept here ([identity function](
>>> https://en.wikipedia.org/wiki/Identity_function)), but I'm not sure
>>> it's good to add it to `Kernel` (as it's imported by default!) - or even in
>>> Elixir core.
>>>
>>> Why should we add this to Elixir core, instead of "extending" with
>>> module?
>>>
>>> ```elixir
>>> defmodule FP do
>>> def identity(a), do: a
>>> end
>>>
>>> def module YourApp do
>>> import FP
>>>
>>> def hello do
>>> 'abcdaabccc' |> Enum.sort |> Enum.chunk_by(&identity/1)
>>> end
>>> end
>>> ```
>>>
>>> For example, that library can be de-facto helper for such FP utility
>>> functions.
>>>
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