> On Jul 10, 2016, at 10:34 PM, Xiaodi Wu <[email protected]> wrote:
>
>
>
> On Sun, Jul 10, 2016 at 11:21 PM, Erica Sadun <[email protected]
> <mailto:[email protected]>> wrote:
>> On Jul 10, 2016, at 10:16 PM, Xiaodi Wu <[email protected]
>> <mailto:[email protected]>> wrote:
>> Given patterns A, B, C, and D, suppose a value x matches A, C, and D,
>> whereas another value y matches B and D, and a third value matches B and C.
>> When evaluating x, y, or z, which statements are executed in the following
>> switch statement? How many of these reach the default case? What happens if
>> I append `fallthrough` at the end of case D? What happens if I move case B
>> after case D? (Yes, I know it is possible to figure it out [my understanding
>> of the answer to the first question is appended below], but I hope you'll
>> agree with me that this is much more difficult to decipher than any switch
>> statement that's currently possible.)
>>
>> ```
>> switch x /* or y, or z */ {
>> case A:
>> // ...
>> continue
>> case B:
>> // ...
>> if C ~= x /* or y, or z, whichever is switched over */ {
>> continue
>> }
>> fallthrough
>
> I'd say it would be fair to disallow continue and fallthrough to occur in the
> same clause
>
> Why should `fallthrough` be prohibited but implicit `break` become mandatory
> in such a clause? If `continue` were to be implemented in this context, I'd
> want the full power of the keyword, including being allowed to `continue`
> conditionally, `continue` with different labels, and round out the case if no
> conditions are satisfied with either `fallthrough` or `break` (or, for that
> matter, `return`, etc.).
I do not understand. `break` is already implicit unless no other code is used.
case something:
if condition { continue }
// ends here. the compiler knows not to go forward and it's not an empty
clause
case somethingElse:
`fallthrough` means "ignore the next case statement and execute its clause".
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