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 <[email protected]> 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) >> ``` >> > -- > You received this message because you are subscribed to the Google Groups > "elixir-lang-core" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/elixir-lang-core/b6b3359a-582b-4b42-88d3-10674c6227a5%40googlegroups.com > <https://groups.google.com/d/msgid/elixir-lang-core/b6b3359a-582b-4b42-88d3-10674c6227a5%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- Regards, Bruce Tate CEO <https://bowtie.mailbutler.io/tracking/hit/f8218219-d2a8-4de4-9fef-1cdde6e723f6/c7c97460-016e-45fb-a4ab-0a70318c7b97> Groxio, LLC. 512.799.9366 [email protected] grox.io -- You received this message because you are subscribed to the Google Groups "elixir-lang-core" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/elixir-lang-core/CAFXvW-77OuMxqK1hPfzzjggM6fX9wTtGiS1Y9%3D7d%2BUiJQsJNXA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
