How to combine the need to localize a result for an if statement
and have to call a method to get proper comparison:
if (((auto x = X.value()).empty())
{
}
instead of having to do the long and winded way
auto x = X.value();
if (x.empty())
{
}
Many times I need the result of a function inside the if but need
to check on other value of the function:
auto x = foo();
if (foo().valid())
{
// use x
}
which should simplify to
if ((auto x = foo()).valid())
{
}
but this code does not work.
I generally need this for regex stuff and it's quite annoying it
doesn't work.
if (!match(s, "\s*(?P<t>.),").empty())
{
// Need the result of match to do things!
}
but this doesn't work:
if (!(auto r = match(s, "\s*(?P<t>.),")).empty())
{
}
which then requires one to do
auto r = match(s, "\s*(?P<t>.),");
if (!r.empty())
{
}
Doesn't seem like a big deal but seems trivial to implement. We
can't always do a simple boolean test of the variable we are
defining:
if (auto x = something)
so we should be able to do
if ((auto x = something).bar())
which is equivalent to
x = something;
if (x.bar())
or even allow
if ((auto x = something) == 3)
{
}
