On Sun, Sep 9, 2018 at 11:08 PM Jonathan Amsterdam <jbamster...@gmail.com>
wrote:
> func ShortestPath(type G Graph(Node, Edge), Node, Edge) (g G, from, to
>> Node) []Edge
>>
>
> I don't think this syntax is valid according to the draft design, or your
> blog post. Node and Edge are used before they are declared.
>
I have not made any statements about that (and Ian/Robert's drafts don't
allow for multiple contracts), but I don't think this is an actual problem,
as long as the references aren't cyclic. You can unify the leafs in the
dependency trees first.
Maybe
>
> func ShortestPath(type Node, Edge, G Graph(Node, Edge)) (g G, from, to
> Node) []Edge
>
> except according to your description, all three type parameters would have
> Graph(Node, Edge) as constraints, which doesn't make sense either.
>
Yes, but my description allows for
func ShortestPath(type Node, Edge interface{}, G Graph(Node, Edge)) (g G,
from, to Node) []Edge
(it's just that an interface{} as the last constraint is implied). But as I
said, i don't think this is an actual issue.
---
BTW, I actually went (like Ian suggested) through the examples in the draft
design
<https://go.googlesource.com/proposal/+/master/design/go2draft-contracts.md#examples>
- at least that specific section, not the inline ones, as I found them
harder to scan for - and they all can be written in my design idea by
simply deleting the contracts and replacing cmp1/cmp2/cmp3 by comparable.
There is a minor detail they brought up, which is that if all struct-keys
are comparable, then the struct itself is too (which IMO should be clear,
but *might* need some language in an actual spec?).
Furthermore, it re-emphasizes that pseudo-interfaces are actually misnamed
and definitely shouldn't be thought of as types themselves, because the
question comes up how they would behave under struct embedding. But IMO
that's a question of phrasing, not of semantics or an unsolvable issue.
>
>> On Sun, Sep 9, 2018 at 8:21 PM Jonathan Amsterdam <jbams...@gmail.com>
>> wrote:
>>
>>>
>>>> FWIW, in my pseudo-interface description
>>>> <https://blog.merovius.de/2018/09/05/scrapping_contracts.html>,
>>>>
>>>
>>> Unrelated to this particular issue, but since you link to your blog
>>> post, I just want to mention that in your graph example,
>>>
>>> func ShortestPath(type Node, Edge) (g Graph(Node, Edge), from, to
>>> Node) []Edge
>>>
>>> will have dynamic dispatches in the body (since g is an ordinary
>>> interface value). The one in the draft design is completely static.
>>>
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