> but I would still love to at least see warnings when comparing non literal structs.
Problem with this is 'how'? When non-literal then they could only be checked at runtime, but the `>`/`=`/`>`/`>=`/`<=` all become BEAM opcodes, no chance to perform detection without explicitly testing, which would slow down those operations *tremendously*. On Monday, October 22, 2018 at 3:00:16 PM UTC-6, Sheharyar Naseer wrote: > > After researching the topic throughly, including the way Protocols are > implemented and the performance drawbacks, I don't believe my initial > proposal is viable. I think the current implementation is great as-is, but > I would still love to at least see warnings when comparing non literal > structs. > > I believe changing Access's implementation > <https://stackoverflow.com/questions/33704618/why-is-elixirs-access-behavior-the-way-that-it-is> > > from Protocol to Behaviour had the same reasoning behind it. > > On Monday, October 22, 2018 at 4:46:04 PM UTC-4, OvermindDL1 wrote: >> >> I wouldn't recommend having the default operators delegate to such a >> protocol, rather just a `cmp` or `compare` or something call, along with a >> warning about using the operators on a struct if it is statically known >> that it is a struct (not too uncommon). >> >> >> On Friday, October 19, 2018 at 4:50:02 PM UTC-6, Sheharyar Naseer wrote: >>> >>> Struct comparisons already throw a warning >>> <https://github.com/elixir-lang/elixir/blob/741dfda9f4be898c647426493f1d17fb9a4b9c53/lib/elixir/src/elixir_expand.erl#L1161-L1165> >>> >>> in Elixir, as it does not make a lot of sense to compare them (except in >>> some very specific cases like date/time): >>> >>> warning: invalid comparison with struct literal ~N"2018-10-19 >>>> 21:35:18.005355". Comparison operators (>, <, >=, <=) perform structural >>>> and not semantic comparison. Comparing with a struct literal is unlikely >>>> to >>>> give a meaningful result. Modules typically define a compare/2 function >>>> that can be used for semantic comparison >>>> >>> >>> But currently this happens only when literal structs are used. For >>> example, when using `Enum.sort` to sort a list of dates, this warning is >>> not raised. I know there already has been some discussion on this >>> <https://groups.google.com/forum/#!topic/elixir-lang-core/eE_mMWKdVYY>, >>> but I believe OvermindDL's suggested approach >>> <https://github.com/elixir-lang/elixir/pull/7274#issuecomment-361362861> >>> to have a Comparable protocol is much better. Kernel's comparison operators >>> would delegate to this protocol, with implementations for common things >>> like Date/Time, and letting it simply throw Protocol.UndefinedError for >>> structs which do not have explicitly implemented it. >>> >> -- 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/5c88ce09-77fb-4827-9d2c-50d0aea72920%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
