Is it possible to declare a closure to have type 'void' somehow?
currently not
Ok. What happens if the last statement in a closure is a call to a void
method?
I would like to exploit this somehow like this:
def someMethod(Closure closure){
if (closure has no return value, or is somehow defined to be 'void'){
closure()
} else {
if (closure()){
doSomething()
} else {
doSomethingElse()
}
}
}
normally it makes no sense to have a logic like this.
I wouldn't ask for it if it wouldn't make at least a bit of sense to me,
but I'm maybe overwhelmed and want to define a WorldDomination API in a
single method definition. So here you go:
interface TreeIterator extends Iterator {
void prune()
}
Instances of this interface are used to walk over a tree structure and
can be used like this:
while (iterator.hasNext()){
Object next = it.next()
doSomethingWith(next)
if (!childrenAreInteresting(next)){
it.prune() // this skips the subtree of the current element
}
}
In groovy it would work somehow like this, with a closure:
iterator.each {
doSomethingWith(it)
childrenAreInteresting(next) // the 'each' implementation takes the
closure result and calls prune() if the result is false
}
But sometimes I want to walk the whole tree and forget about having to
return a value:
iterator.each {
doSomethingWith(it)
true
}
I would like to get rid of the forced 'true' as the last statement.
Felix
