Few things

[Chris Nicholson-Sauls]

Don Clugston wrote:
> Chris Nicholson-Sauls wrote:
>> Don Clugston wrote:
>>> Lionello Lunesu wrote:
>>>>> 7) From the FAQ: 
>>>>
>>>>> Many people have asked for a requirement that there be a break
>>>>  > between cases in a switch statement, that C's behavior of
>>>>  > silently falling through is the cause of many bugs.
>>>>  > The reason D doesn't change this is for the same reason that
>>>>  > integral promotion rules and operator precedence rules were
>>>>  > kept the same - to make code that looks the same as in C
>>>>  > operate the same. If it had subtly different semantics, it
>>>>  > will cause frustratingly subtle bugs.
>>>>
>>>>> I agree with both points of view. My idea: calling this
>>>>  > statement differently (like caseof) instead of "switch"
>>>>  > (like in Pascal), so you can change its semantics too,
>>>>  > removing the falling through (you may use the Pascal
>>>>  > semantic too).
>>>>
>>>> Sorry to hijack your point here, but this got me thinking:
>>>>
>>>> Why not use "continue" for seeping through to the next case 
>>>> statement? DMD could then complain if a case does not end with 
>>>> break/continue/goto/return and silently insert a assert(0) before 
>>>> each case (the way it does for functions that return a value.)
>>>
>>> Doesn't
>>>
>>> for (c;;) {
>>>   switch (c) {
>>>   case 'a': continue;
>>>   case 'b': break;
>>>   }
>>> }
>>>
>>> already have a meaning?
>>
>> I can't think of any other case where this problem would show (aside 
>> from other looping statements, so the fix is the same).  Since this is 
>> probably not an overly common case (I've done it myself, but not very 
>> often), I don't think writing a label on the loop would be a big deal.
> 
> That's fine. The issue is that it would silently break existing code.

Okay, I'll grant you that.  Maybe require the 'switch' keyword after the 
continue?  Or else require a label on the switch... but then continues 
start acting slightly different from breaks.

No easy way out, it seems.

-- Chris Nicholson-Sauls