Hi Paul,
Thanks for the proposal. My personal take is that a Enum.reduce/3 + the
relevant Map operation should be the way to go, because this can easily
lead to a combination of replace_many, update_many, put_new_many, etc.
Especially because the many operations likely wouldn't be any more
efficient than the Enum.reduce/3 call.
On Thu, Dec 30, 2021 at 10:42 PM Paul Alexander <paul.aj.mans...@gmail.com>
wrote:
> Hi everyone,
>
> I would like to discuss the possibility of adding two new functions to
> each of the Map and Keyword modules; replace_many/2 and update_many/3.
> Their purpose is to update maps and keyword lists providing either a
> keyword list of the key-value pairs which need to updated, or a list of
> keys and a function which operates on the existing values of those keys.
>
> Far too often I find myself needing to call replace!/3 or update!/3
> several times from within a pipeline, or even needing to use a
> for-comprehension or Enum.reduce/3 to update a map in "one shot", when it
> feels like there should be a function for this.
>
> There are a number of reasons as to why I think these functions should be
> considered, but I'll provide only two for now:
>
> 1. There is already a way of updating multiple key-value pairs
> simultaneously for maps using %{map | k1 => v1, k2 => v2}. But this
> unfortunately does not support passing a literal keyword list after the
> cons operator.
> - My first instinct was to see if I could expand the special update
> syntax to handle keyword lists, but I wasn't able to find where it is in
> the codebase. If someone could point that out for me because I'd like to
> learn how it works, I'd greatly appreciate it.
> 2. It would be somewhat analogous to Kernel.struct!/2, where keyword
> lists can be passed as the second argument to update several fields within
> a struct. Seeing as how structs are maps, it only makes sense there should
> be a way that maps could be updated in a similar manner from within the Map
> module.
>
>
> I have already implemented the four functions, complete with docs,
> examples, and passing tests. But I wanted confirmation from the core team
> if a PR is welcome for this addition. Any opinions?
>
> --
> 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 elixir-lang-core+unsubscr...@googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/elixir-lang-core/7c79a2b8-3a3c-48f9-a4d0-7d2e07c851e4n%40googlegroups.com
> <https://groups.google.com/d/msgid/elixir-lang-core/7c79a2b8-3a3c-48f9-a4d0-7d2e07c851e4n%40googlegroups.com?utm_medium=email&utm_source=footer>
> .
>
--
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 elixir-lang-core+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/elixir-lang-core/CAGnRm4%2BnxBvFjbfR4rypSaNaqS2a70ojFjT_DL4AVjouynBX_A%40mail.gmail.com.
