request switch statement with common block

[Andrei Alexandrescu]

On 8/3/13 10:21 AM, JS wrote:
> On Saturday, 3 August 2013 at 16:16:24 UTC, Ary Borenszweig wrote:
>> On 8/3/13 11:38 AM, JS wrote:
>>>
>>> switch (cond)
>>>     common: always executed code here
>>>     case A : etc...
>>>     ....
>>> }
>>>
>>> instead of
>>>
>>> if (cond) { always executed code here  }
>>> switch (cond)
>>>     case A : etc...
>>>     ....
>>> }
>>>
>>> which requires modification of the condition twice when necessary
>>
>> Do you mean this?
>>
>> switch(cond) {
>>   case A:
>>     common_code();
>>     // something
>>   case B:
>>     common_code();
>>     // something else
>> }
>>
>> (common_code() must not be executed if it doesn't hit any switch case)
>
> exactly

No because your initial rewrite suggested zero is special. But zero has 
no special meaning to the switch statement. Consider:

switch (cond)
{
common: ...
case 0: ...
...
}


Andrei