On Thu, Dec 05, 2019 at 02:06:50PM -0600, Segher Boessenkool wrote: > Hi! > > On Thu, Dec 05, 2019 at 05:03:43PM +0000, Jonathan Wakely wrote: > > C++17 introduces a nice feature, with rationale similar to declaring > > variables in a for-loop init-statement: > > > > if (auto var = foo(); bar(var)) > > Similar to GNU C statement expressions, which are *also* only a good > idea to use in limited cases. > > > The variable is only in scope for the block where you need it, just > > like a for-loop. > > > > Unfortunately nearly every time I've tried to use this recently, I've > > found it's impossible in 80 columns, e.g. this from yesterday: > > > > if (auto __c = __builtin_memcmp(&*__first1, &*__first2, __len) <=> > > 0; __c != 0) > > return __c; > > > > When you're forced to uglify every variable with a leading __ you run > > out of characters pretty damn quickly. > > If using this "nice feature" forces you to uglify your code, then maybe > it is not such a nice feature, and you should not use it.
I disagree, it is a nice feature, without quotes. It's Good Style not to leak variables into enclosing scopes. > If you have issues with scoping your functions are WAY too long already. I don't think that's the case here. -- Marek Polacek • Red Hat, Inc. • 300 A St, Boston, MA
