Andrei Alexandrescu wrote:
Chad J wrote:
So, switch-case statements are a frequent source of nasty bugs. Fixing
them (well) requires breaking backwards compatibility.
Any chance this will happen for D2?
(This is intended as more of a reminder and simple curiosity than a
discussion.)
I wish very much that a transferring control flow statement (break,
return, goto etc.) is required at the end of each case. Then, the rare
case when you want to break through is easy to implement as goto case
xxx; and all is good.
Walter's answer to that has put me to silence for good. "But I use
fall-through all the time!" I then knew the feature will never make it.
Andrei
For what its worth, in a (very domain specific) scripting language I've been working on, I
used 'continue' to implement fall-through, and haven't felt too bad about it. That and
being able to do (case A, B, C:) helps for the most common (IME) sort of use.
//////////////////////////////////////////////////
.__receive system ( cmd: STR, @params )
switch ( cmd .lowercase .tosym )
case 'lo', 'login':
user.tell( "(LOgin has been deprecated; please start using COnnect
instead.)")
continue;
case 'co', 'connect':
uname, pwd <- params;
who = #Database::User.lookup( uname )
if ( who.valid && who.accept_password( pwd ) )
return .accept( user, who );
end
// ... and so on ...
end
end
//////////////////////////////////////////////////
-- Chris Nicholson-Sauls
