Need trailing comma before newline in composite literal

[r2p2]

Hi,

after one year, I try to relearn go. (Thanks to the two years birthday news everywhere.)

I wanted to start with a reimplement his ( http://wh3rd.net/practical-go/#(1) ) url shortener. But on page 12 ( http://wh3rd.net/practical-go/#(12) ) I stumbled over weird syntax.

For me it is not logical why I have to set there a comma. Is there a deeper reason?

With kind regards

r2p2

[Evan Shaw]

On Thu, Nov 17, 2011 at 10:01 AM, r2p2 <robert...@gmx.net> wrote:
> For me it is not logical why I have to set there a comma. Is there a deeper
> reason?

Yes, it's because of automatic semicolon insertion. Semicolons are
automatically inserted at the end of a line in many situations,
including when the last token is a parenthesis. (See
http://golang.org/doc/go_spec.html#Semicolons)

The comma tells the compiler "don't insert a semicolon here; this
isn't the end of a statement."

- Evan

[Andrew Gerrand]

It's not just that. It also means that you can more easily re-order the lines of a literal without needing to worry about adding or removing commas. (As is the case with JavaScript, for example.)

Andrew

[r2p2]

Well, this is a good point. But it still doesn't look natural.

[John Asmuth]

Source code of any language doesn't look natural until you've been staring at it for a while.

Since I've been writing Go for more than a year, the comma at the end looks like the most natural thing in the world :)

[Bobby Powers]

On Fri, Nov 18, 2011 at 5:17 AM, Andrew Gerrand <a...@golang.org> wrote:

It's not just that. It also means that you can more easily re-order the lines of a literal without needing to worry about adding or removing commas. (As is the case with JavaScript, for example.)

It also makes version control diffs nicer when adding items to lists/structure initializations, etc.  It gets rid of the:

-     someItemThatHasntActuallyChanged

+     someItemThatHasntActuallyChanged,

noise, which makes me happy.

yours,

Bobby

[pg...@redhat.com]

Because of this reason I started feeling it natural :D thanks Andrew Gerrand for pointing out.