Today you can do it like this:
var = Enum.reduce(@list, &{:|, _. [&1, &2]}
@type foo :: unquote(var)
But it may be worth introducing something like you describe but it probably
makes sense to do it via a construct, such as @type foo :: one_of(@var)
that does the conversion for you. I think automatically converting the list
can be confusing, because people may think that [:foo, :bar] implies a
specific ordering, for example.
I am just not sure of a good name. one_of may conflict with existing code.
On Sat, May 16, 2020 at 6:25 AM Kip <[email protected]> wrote:
> It's not uncommon to have domain overlap between lists of valid tokens
> (used for validations) and type specs. For example:
>
> @standard_formats [
> :standard,
> :accounting,
> :currency,
> :percent
> ]
>
> @currency_formats [
> :currency,
> :accounting,
> :currency_long,
> :currency_short
> ]
>
> @currency_symbol [
> :standard,
> :iso
> ]
>
> @type standard_formats :: :standard | :currency | :accounting | :short |
> :long
> @type currency_formats :: :currency_short | :currency_long |
> :decimal_short | :decimal_long
> @type currency_symbol :: :standard | :iso
>
> It would go good to remove one source of error by being able to allow
> compile time use of a list as the subject of @typespec. For example:
>
> @type currency_symbol :: @currency_symbol # Any compile-time resolvable
> list
>
> Of course a macro can be introduced to do this but its quite difficult to
> achieve since it requires manual manipulation of AST.
>
> Proposal worth considering? Or consign to the history of my
> less-than-helpful ideas :-)
>
>
> --
> 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/36f821aa-d718-48aa-a9e8-2f6d5e440632%40googlegroups.com
> <https://groups.google.com/d/msgid/elixir-lang-core/36f821aa-d718-48aa-a9e8-2f6d5e440632%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 [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/elixir-lang-core/CAGnRm4%2BRfGarTtrtQ8aeYkLPxWNA_h%3DuggUn%3DWYRiTO7Evr6dg%40mail.gmail.com.
