dolfin team mailing list archive

["Garth N. Wells" <gnw20@xxxxxxxxx>]

On 06/03/11 21:29, 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, noreply@xxxxxxxxxxxxx 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.
> 

It was an if -- else.

Garth

> 
>>
>> 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.
> 
> 
> -- 
> Marie
> 
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