I might (if forced) do it as:

// immediately executed lambda left of '?'
auto rez = ( [&]{ return true ; }() ? "42" : "not 42" ) ;

Although there is this thing called "code readability" that matters. A lot.


On Thu, 10 Sep 2020 at 23:36, Ville Voutilainen via Std-Proposals <
std-proposals_at_[hidden]> wrote:

> On Fri, 11 Sep 2020 at 00:18, Dmitry Dmitry via Std-Proposals
> <std-proposals_at_[hidden]> wrote:
> >>
> >> You can probably already have a similar outcome with:
> >>
> >> return [&] { auto It = Cont.find(42); return It == Cont.end() ? 0 :
> >> It->second; }();
> >>
> >> which is not that much longer.
> >
> >
> > Yeah... Right.
> >
> > But what about consistency (between regular if()'s and ternary
> operators)?
> > It just reminds me how initially, auto parameters were invented in
> lambdas and then they were "ported" to regular function.
> > Ditto here, initially init-statements were introduced in regular if()'s,
> but kind-of-forgotten in ternary operators?
>
> It's quite different. The left-hand side of a ternary operator is an
> arbitrary expression with no initial hint that a ternary operator
> will eventually follow. In the init-statement-and-condition of an
> if-statement, we know that we're going to see either
> an init-statement or a condition, we have context that tells both
> human readers and computer parsers what to expect.
> That's not the case for a ternary expression. Furthermore, it would be
> bloody weird to introduce a statement-expression
> like
> (auto It = Cont.find(42); It == Cont.end())
> only for ternary expression left-sides. Such statement-expressions are
> a thing in GCC as extensions; if you want an expression
> that contains statements, write a lambda.
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