OK, so let's look at the general problem. The structure is this:
doSomething();
while (someCondition())
{
doSomethingElse();
doSomething();
}
...and you want to factor out the doSomething() call so that it only
has to be specified once.
Is that correct, Aristotle?
The "gotcha" is that the first doSomething() is unconditional, while
the first doSomethingElse() should only happen if the loop condition
is met (which means just moving the test to the end of the block
doesn't solve the problem).
IFF the doSomething() can be reasonably combined with the conditional
test, then Bruce's solution works, but that won't necessarily be the
case in general. Overall, the goal is to ensure that by the end of
the loop the program is in the state of having just called
doSomething(), whether the loop runs or not - while also ensuring that
the program is in that state at the top of each loop iteration.
It does seem like a closure trait sort of thing, but I don't think
it's currently provided by the p6 spec.
