Quick question about the new Contracts Draft Proposal

[Jon Bodner]

Hello,

I did a first read through the proposal and it looks very good. I had one question: when giving the example of how to implement Sorting using orderedSlice, the type parameter is declared to be comparable. Should that be contracts.Ordered?

Thanks,

Jon

[Mandolyte]

I missed this. Do you have a link to the proposal?

[Jon Bodner]

https://go.googlesource.com/proposal/+/master/design/go2draft-contracts.md (Updated on 7/25/2019)

GopherCon 2019 Talk summary: https://about.sourcegraph.com/go/gophercon-2019-generics-in-go

Jon

[alanfo]

 Yes, it should be contracts.Ordered to justify the use of the '<' operator.

The proposed new built-in comparable contract will only permit one to use '==' or '!='.

I agree that the revised design is very good, contracts are now far more intelligible than they were and the whole thing just feels much more Go-like to me :)

As the response so far has been generally positive, hopefully it won't be too long before this proceeds to the 'proposal' stage.

Alan

[Ian Lance Taylor]

On Sun, Jul 28, 2019 at 1:15 PM Jon Bodner <j...@bodnerfamily.com> wrote:
>
> I did a first read through the proposal and it looks very good. I had one question: when giving the example of how to implement Sorting using orderedSlice, the type parameter is declared to be comparable. Should that be contracts.Ordered?

Yes, thanks. Will update.

Ian

[Mandolyte]

In this code snippet:

func Map(type S, Element)(s S, f func(Element) Element) S {
	r := make(S, len(s))
	for i, v := range s {
		r[i] = f(s)
	}
	return r
}

Shouldn't the line in the loop be: r[i] = f(v)

[Ian Lance Taylor]

On Mon, Jul 29, 2019 at 2:35 PM Mandolyte <ceci...@gmail.com> wrote:
>
> In this code snippet:
>>
>> func Map(type S, Element)(s S, f func(Element) Element) S {
>> r := make(S, len(s))
>> for i, v := range s {
>> r[i] = f(s)
>> }
>> return r
>> }
>
> Shouldn't the line in the loop be: r[i] = f(v)

Yes. Thanks.

Ian

> On Monday, July 29, 2019 at 2:17:22 PM UTC-4, Ian Lance Taylor wrote:
>>
>> On Sun, Jul 28, 2019 at 1:15 PM Jon Bodner <j...@bodnerfamily.com> wrote:
>> >
>> > I did a first read through the proposal and it looks very good. I had one question: when giving the example of how to implement Sorting using orderedSlice, the type parameter is declared to be comparable. Should that be contracts.Ordered?
>>
>> Yes, thanks. Will update.
>>
>> Ian
>

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[Qais Patankar]

In this:

func Map(type S, Element)(s S, f func(Element) Element) S {

Why is Slice not mentioned anywhere?

Shouldn't it be:

func Map(type S, Element Slice) [..]

On Tuesday, 30 July 2019 09:04:26 UTC+9, Ian Lance Taylor wrote:

On Mon, Jul 29, 2019 at 2:35 PM Mandolyte <ceci...@gmail.com> wrote:
>
> In this code snippet:
>>
>> func Map(type S, Element)(s S, f func(Element) Element) S {
>> r := make(S, len(s))
>> for i, v := range s {
>> r[i] = f(s)
>> }
>> return r
>> }
>
> Shouldn't the line in the loop be: r[i] = f(v)

Yes.  Thanks.

Ian

> On Monday, July 29, 2019 at 2:17:22 PM UTC-4, Ian Lance Taylor wrote:
>>
>> On Sun, Jul 28, 2019 at 1:15 PM Jon Bodner <j...@bodnerfamily.com> wrote:
>> >
>> > I did a first read through the proposal and it looks very good. I had one question: when giving the example of how to implement Sorting using orderedSlice, the type parameter is declared to be comparable. Should that be contracts.Ordered?
>>
>> Yes, thanks.  Will update.
>>
>> Ian
>
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> To unsubscribe from this group and stop receiving emails from it, send an email to golan...@googlegroups.com.

[alan...@gmail.com]

Yes, it should.

Alan