> How about supporting type aliases as Scala does?
In theory I think that should be achievable today, using trait inheritance:
trait MyT : Clone, Eq {}
...at least, I *think* we allow multiple trait inheritance. Not sure what
the syntax is!
On Sat, Feb 1, 2014 at 6:12 PM, Vladimir Lushnikov <
vladi...@slate-project.org> wrote:
> Placing type bounds before the name of the thing you are trying to declare
> feels unnatural to me. And the generic block is far too much boilerplate!
>
> How about supporting type aliases as Scala does? So you write:
>
> type MyT = Clone + Eq
> fn foo<MyT, U>(t: T, u: U) -> ...
>
> and the 'type' is just an alias for any type that has Clone + Eq?
>
> Obviously the above only solves repeating yourself for complex type
> constraints.
>
> Also, reusing 'for' would be confusing as well, because you expect a loop
> there, not a generic type bound. How about 'any':
>
> any <T: Clone + Eq, U> fn foo (t: T, u: U) -> ...
>
> ?
>
>
> On Sat, Feb 1, 2014 at 11:06 PM, Benjamin Striegel <ben.strie...@gmail.com
> > wrote:
>
>> Another point in favor of this plan is that it would eliminate the need
>> to put type parameters directly after the `impl`, which to be honest *is*
>> pretty weird and inconsistent with the rest of the language. But I'm still
>> not sure how I feel about the look of it:
>>
>> for <T: Clone+Eq, U> fn foo(t: T, u: U) -> (T, U) {
>>
>> If you choose *not* to wrap after the type parameters there, you're
>> really obscuring what the heck you're trying to declare.
>>
>> Heck, maybe what we're really asking for is for the ability to have
>> "generic blocks" within which type parameters can be declared once:
>>
>> for <T: Clone+Eq, U> {
>> fn foo(t: T, u: U) -> (T, U) {
>>
>> ...but that's even *more* boilerplate!
>>
>>
>>
>>
>> On Sat, Feb 1, 2014 at 5:59 PM, Benjamin Striegel <ben.strie...@gmail.com
>> > wrote:
>>
>>> > Yes, and I don't have a solution for that.
>>>
>>> Well, it's not like we don't already stumble here a bit, what with
>>> requiring ::<> instead of just <>. Not sure how much other people value the
>>> consistency here.
>>>
>>>
>>> On Sat, Feb 1, 2014 at 5:58 PM, Corey Richardson <co...@octayn.net>wrote:
>>>
>>>> On Sat, Feb 1, 2014 at 5:55 PM, Benjamin Striegel
>>>> <ben.strie...@gmail.com> wrote:
>>>> > First of all, why a new keyword? Reusing `for` here would be totally
>>>> > unambiguous. :P And also save us from creating the precedent of
>>>> multi-word
>>>> > keywords.
>>>> >
>>>>
>>>> I'd be equally happy with for instead of forall.
>>>>
>>>> > Secondly, currently Rust has a philosophy of use-follows-declaration
>>>> (i.e.
>>>> > the syntax for using something mirrors the syntax for declaring it).
>>>> This
>>>> > would eliminate that.
>>>> >
>>>>
>>>> Yes, and I don't have a solution for that.
>>>>
>>>
>>>
>>
>> _______________________________________________
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>> https://mail.mozilla.org/listinfo/rust-dev
>>
>>
>
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