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. If you have issues with scoping your functions are WAY too long already. Segher
