Confused about "syntax error: unexpected comma, expecting {" with multiple outputs

[Brendan Tracey]

I don't understand why f2 compiles but f1 does not. Help understanding this error would be appreciated

http://play.golang.org/p/S4n6Nff1W9

[Scott Lawrence]

On Fri, 1 Feb 2013, Brendan Tracey wrote:

> I don't understand why f2 compiles but f1 does not. Help understanding this
> error would be appreciated

Because []Datapoint is a type, not a value. You want

return []Datapoint{}, nil

When you write 'var a []Datapoint', that's equiv. to 'var a := []Datapoint{}'.

>
> http://play.golang.org/p/S4n6Nff1W9
>
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--
Scott Lawrence

go version go1.0.3
Linux baidar 3.7.4-1-ARCH #1 SMP PREEMPT Mon Jan 21 23:05:29 CET 2013 x86_64 GNU/Linux

[Dmitri Shuralyov]

If, instead of using var blah = []Datapoint you did blah := []Datapoint, you would get the same error.

You want to write []Datapoint{} instead.

Interestingly, the error description literally tells you how to fix the problem.

[Brendan Tracey]

Thanks for the help. It does literally tell me how to fix the problem, though not really the source of the problem (which is that I was returning a value, not a type). I was confused about it telling me that there is a syntax error. In other languages I've used, "unexpected comma, expecting {" would generally mean I had forgotten an open brace. I'm not complaining about the error, from the compiler's perspective it is a syntax error.