On Sun, Mar 06, 2011 at 10:29:10PM +0100, Marie E. Rognes wrote:
> On 03/06/2011 10:22 PM, Anders Logg wrote:
> >On Sun, Mar 06, 2011 at 09:08:10PM +0000, Garth N. Wells wrote:
> >>
> >>
> >>On 06/03/11 21:02, Marie E. Rognes wrote:
> >>>On 03/06/2011 09:30 PM, nore...@launchpad.net wrote:
> >>>> if (parameters["max_dimension"].change_count()> 0
> >>>> && V.dim()> max_dimension)
> >>>>+ {
> >>>> return true;
> >>>>-
> >>>>- // Otherwise, not done.
> >>>>- return false;
> >>>>+ }
> >>>>+ else
> >>>>+ return false;
> >>>> }
> >>>
> >>>
> >>>I notice that my early returns keep getting moved into else clauses... I
> >>>find this approach less readable, especially when there are nested ifs.
> >>>Why is it the preferred way?
> >>>
> >>
> >>Because your comment basically says else, so I'd say it's better to have
> >>the code say it consistently.
> >>
> >>I find it easier to follow, because it's clear that the function exits
> >>from the conditional block. The return value is either true or false
> >>depending on the one true/false evaluation.
>
>
> The code is an if -- else if -- else. I don't see how moving that
> into an if, if -- else increases consistency.
>
>
> >
> >I'm not sure we're talking about the same thing here, but I think the
> >following examples are *good* practice:
> >
> >1. Early return to get rid of special cases
> >
> >void foo()
> >{
> > // Get rid of some case
> > if (...)
> > return;
> >
> > // Get rid of another case
> > if (...)
> > return;
> >
> > // Do main bulk of work here
> > ...
> >}
> >
> >Alternative using if/else will force main code in one indentation
> >level.
> >
> >2. Fallback return at end of block
> >
> >bool foo()
> >{
> > // Handle case 1
> > if (...)
> > {
> > ...
> >
> > return true;
> > }
> >
> > // Handle case 2
> > if (...)
> > {
> > ...
> >
> > return true;
> > }
> >
> > // No foos found
> > return false;
> >}
>
>
> Yep, I prefer 2. to an if -- else if (-- else if) -- else.
It's also logical since the 'else' has no effect. So the policy can be
to remove code that has zero effect.
--
Anders
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