X := "somevalue" works in the main func, but not outside

[pritesh (Pritesh Ugrankar)]

Hi,

Occasional Go dabbler here so kindly pardon if this is obvious.

I am trying this with Go version 1.7.3 on Windows 7 (74 Bit):

package main

import "fmt"

x := "checkscope"

func main() {
	fmt.Println(x)
} 

The editor shows this error ( i am using gvim 8 on Windows with the vim-go Plugin)
main.go|5 col 1| : expected declaration, found 'IDENT' x

And when I try to compile I get the following error:

C:\Users\ugrankar\src\golang-book\chapter3>go build main.go
# command-line-arguments
.\main.go:5: syntax error: non-declaration statement outside function body

I guess this means, the x:= “something” can be only used inside a function.

But then the following works without a problem:

package main

import "fmt"

var x string = "checkscope"

func main() {
	fmt.Println(x)
}  

So is there something special about := that works only inside a function?

Regards,
pritesh

[calmh (Jakob Borg)]

Yes. Short variable declarations may appear only inside functions.

[dfc (Dave Cheney)]

What calmh said. This makes the parser simpler, you don’t need a symbol table if you require that each declaration at the top level being with one of the seven declaration keywords.