expected switch expression, found simple statement

[Tong Sun]

Hi, 

In the following of my snippet, there are two switch statements, one being "switch t := token.(type)", and the second being "switch inElement". I'm wondering why I can't make the second switch statement using the first format, I.e., why I can't use "switch inElement := t.Name.Local" for my second switch statement? It will give "expected switch expression, found simple statement" error BTW.

Thanks

// Inspect the type of the token just read.

switch t := token.(type) {

case xml.StartElement:

// If we just read a StartElement token

inElement := t.Name.Local

switch inElement {

case "Comment":

{

var c Comment

// decode a whole chunk of following XML into the

// variable c which is a Comment (t above)

decoder.DecodeElement(&c, &t)

fmt.Printf("C: %s\n", c.Comment)

}

case "Included":

{

var r Included

decoder.DecodeElement(&r, &t)

fmt.Printf("I: %s\n", r.Included)

}

}

default:

}

[Jan Mercl]

On Tue, Oct 27, 2015 at 8:07 PM Tong Sun <sunto...@gmail.com> wrote:

> why I can't use "switch inElement := t.Name.Local" for my second switch statement? It will give "expected switch expression, found simple statement" error BTW.

Because the specification's grammar of a type switch differs from the one of an expression switch.

This should work:

        switch inElement := t.Name.Local; inElement {
        case "Comment":

                ...

        }

--

-j

[Dan Kortschak]

On Tue, 2015-10-27 at 19:20 +0000, Jan Mercl wrote:
> This should work:
>
> switch inElement := t.Name.Local; inElement {
> case "Comment":
> ...
> }

Or even just `switch t.Name.Local {...` since the value is only being
used to test against.