For a start, you'd have to modify that with s[was][will be].
Indeed, that is precisely the Perl 6 solution to the problem: time travel. Context in Perl 6 is not determined at compile time or even at evaluation time, but rather at binding time, which is even later than that.
Think of it as JIT context.
'Course, Perl 6 also defines what it means to have a list in scalar context, and unlike Perl 5 defines it to not throw away information. You never get return-the-last-value semantics unless you ask for it specifically via subscripting.
A list in scalar context just turns into an array object.
An array in scalar context also just remains an array object rather than presuming that scalar context means numeric context. This lazy kind of time travel means the array can behave
correctly and consistently in numeric context, boolean context, string context, or even, horrors, referential context.
Unfortunately, you also need time travel to have a finished Perl 6. Fortunately it's the kind of time travel that can be implemented by waiting, as long as someone else isn't... :)