Shouldn't we support custom step types (like we do for first and last) like in this diff <https://github.com/elixir-lang/elixir/compare/master...v0idpwn:patch-1>?
Em terça-feira, 13 de abril de 2021 às 18:17:35 UTC+3, José Valim escreveu: > Given Dialyzer does not natively support stepped ranges, I don't think we > should emulate them and have 1..10//1 and 1..10//2 to two very distinct > things. :( > > On Tue, Apr 13, 2021 at 5:03 PM [email protected] <[email protected]> > wrote: > >> While working with the v1.12.0 rc0 release, I wrote the following >> typespec: >> >> @spec my_fun(1..10//2) :: boolean() >> >> which resulted in the following error: >> >> == Compilation error in file lib/foobar.ex == >> ** (CompileError) lib/foobar.ex:6: type ..///3 undefined (no such type in >> Foobar) >> >> My confusion stemmed from my belief that ranges in typespecs were >> interpreted by Elixir and expanded at compile time (e.g. 1..10 to >> 1|2|3|4|5|...) since the syntax (first..last) matches the Elixir range >> syntax and Erlang has no native ranges. Of course, this was wrong because >> while Erlang doesn't have ranges, *Dialyzer* does. >> >> While I can't think of the last time I wanted the contract of my function >> to be "only accepts odd integers between 1 and 100", it also seems like a >> curious omission. From the perspective of someone with good knowledge of >> Elixir but limited knowledge of Erlang and Dialyzer, I had originally >> believed that this was some kind of mistake or oversight. >> >> There also might be a use-case in providing additional information to >> Dialyzer, such as: >> @spec odd?(1..10//2) :: true >> @spec odd?(2..10//2) :: false >> >> Would it be worth taking a type such as 1..10//2 and compiling it to >> 1|3|5|7|9 for Dialyzer? >> >> -- >> 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/d9415490-4285-48fe-a863-4d778ccc962an%40googlegroups.com >> >> <https://groups.google.com/d/msgid/elixir-lang-core/d9415490-4285-48fe-a863-4d778ccc962an%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/b164a0dc-572e-4ec6-b62b-7d2ddff33fa7n%40googlegroups.com.
