[OpenLayers-Dev] Semicolons

[John Cole]

To add a different opinion, I always use the semicolons.  Why?  To avoid
side effects and avoid ambiguity.  With large projects, we have run into the
situation where a dangling line creates syntactically legal, but logically
wrong code.  And it can be confusing trying to understand why removing (or
adding) a blank line can change how a program operates.

>From the O'reilly JS book:

return
true

Is interpreted as 

return;
true;

When you really meant "return true;"

You can also find weird assignments when someone doesn’t remove a '+' at the
end of a concatenation that would be easier to see if the ';' were always at
the end of the line.

Remember, JS is actually putting the ';' in, it's just trying to figure out
where they go.  It's not that they are not needed; it's a matter of who puts
them in.

"Omitting semicolons is not a good programming practice; you should get in
the habit of using them." --JavaScript, The Definitive Guide, O'Reilly, 4th
Edition

John



-----Original Message-----
From: dev-bounces at openlayers.org [mailto:dev-bounces at openlayers.org] On
Behalf Of Erik Uzureau
Sent: Friday, August 31, 2007 9:51 AM
To: Paul Spencer
Cc: dev at openlayers
Subject: Re: [OpenLayers-Dev] Semicolons

Excellent!

Thanks Paul and Jeff for your quick and insightful responses. I agree
with this approach and will go back and remove those extra ;'s I've
just added. :-)

Erik

On 8/31/07, Paul Spencer <pspencer at dmsolutions.ca> wrote:
> Erik,
>
> I am in favour of a coding style that is syntatically (?) correct
> while requiring the minimum amount of typing.
>
> I believe that using this style:
>
> var foo = function() {};
>
> does require the semi-colon at the end of the statement while:
>
> function foo() {}
>
> doesn't.  I have tested this with jslint and it reports a warning if
> the semi-colon is missing in the first case and not in the second
> case.  An extra semi-colon does not cause a syntax warning either.
>
> As you know, javascript allows some laxity with semi-colons and the
> only time it really bites you is when you want to compress stuff, so
> I'm not really strongly opinionated if this is for test cases that
> are unlikely to be compressed.  However, as a matter of habit, I
> believe that we should use semi-colons in the first style of coding
> and not in the second because the encourages an understanding of why
> the semi-colons are required (or not) which means we will understand
> the language a little better.
>
> Cheers
>
> Paul
>
>
> On 31-Aug-07, at 10:25 AM, Erik Uzureau wrote:
>
> > In a bout of friday afternoon lunacy, I began adding semicolons to the
> > end of the function declarations in the tests files.
> >
> > The original impetus for this was that I noticed that doing so reduced
> > the number of errors reported by the JSEclipse plugin that I use for
> > my JS development work. Certainly neither an urgent nor universal
> > change, but I need to spin some brain cycles.
> >
> > Someone else has brought it to my attention that s/he is *not* in
> > favor of that style....
> >
> > I prefer:
> >
> > function foo() {};
> > and
> > var foo = function() {};
> >
> > whereas s/he prefers:
> >
> > function foo() {}
> > and
> > var foo = function() {}
> >
> >
> >
> > do others have an opinion on this? the OC in me wants everything to be
> > the same in our code, and I'm more than willing to rollback the
> > changes I've just done if people are in favour of the other way of
> > doing it.
> >
> > Please cast a vote if you have some thoughts.
> >
> > Erik
> > _______________________________________________
> > Dev mailing list
> > Dev at openlayers.org
> > http://openlayers.org/mailman/listinfo/dev
>
> +-----------------------------------------------------------------+
> |Paul Spencer                          pspencer at dmsolutions.ca    |
> +-----------------------------------------------------------------+
> |Chief Technology Officer                                         |
> |DM Solutions Group Inc                http://www.dmsolutions.ca/ |
> +-----------------------------------------------------------------+
>
>
>
>
>
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>
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