This works:
b, a := 1, struct{ x int }{2}
But this doesn’t:
var a struct{ x int }
b, a.x := Returns1And2()
But this does:
var a struct{ x int }
var b int
b, a.x = Returns1And2()
And this does:
var a int
b, a := Returns1And2()
Matt
On Tuesday, January 9, 2018 at 5:59:49 PM UTC-6, Kevin Malachowski wrote:
>
> It is not a new declaration, it is definitely an assignment. This can be
> determined because (in Go) a new declaration has effects when closing over
> variables: https://play.golang.org/p/a_IZdOWeqYf
>
> (ignore the obvious race condition; it works the same but looks uglier
> with the requisite locks: https://play.golang.org/p/OXBK5XEg9Yf)
>
> On Tuesday, January 9, 2018 at 2:20:06 PM UTC-8, Ayan George wrote:
>>
>>
>>
>> On 01/09/2018 04:45 PM, Ian Lance Taylor wrote:
>> > On Tue, Jan 9, 2018 at 1:02 PM, Jim Bishopp
>> > <james....@gmail.com> wrote:
>> >>
>> >> Has there ever been a discussion about allowing new identifiers and
>> >> selectors in short variable declarations?
>> >>
>> >> var a struct { x int } b, a.x := 1, 2
>> >>
>> >> ERROR: expected identifier on left side of :=
>> >
>> > That idea appears in https://golang.org/issue/377, along with many
>> > others.
>> >
>>
>> I had the same question myself. I settled on the idea that that is a
>> short declaration -- not an assignment -- though it does re-declare
>> existing variables (of the same type!). That behaves like assignment
>> but I think it is still declaration.
>>
>> But its behavior makes sense if you consider that you can't declare or
>> re-declare struct member.
>>
>> -ayan
>>
>
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