On Fri, Jan 16, 2009 at 12:34 AM, Reinier Zwitserloot <[email protected]>wrote:
> The use case is writing your own language features.
Well. A rather limited set of language feature, involving continue, break
and return.
> Then 'foreach' is utterly unneccessary. You could just write it as a
> library. Same story for ARM-like proposals (File.doForEachLine),
> functional style collections operations, such as filter, flatten, and
> map, map foreach, a synchronized-like block construct for semaphores
> and locks, and whatever else you can think up.
You don't need long returns for that.
foreach don't need it, becase as the name implies it is for _each_ ...
If you want to exit after a particular condition you can do it like this:
public T findFirst(#(boolean(T)) pred)
{
if(pred(first))
return first;
else
return rest.findFirst(pred);
}
Anytime you use a
> closure to represent the body of such a 'statement', obviously the
> return, continue, and break statements have to be transparent or it's
> a very leaky abstraction.
That argument might have worked if it was allready true for the existing
java, but it isn't. What does "break" mean here?
final int myVar;
{
int blah = 0;
if(blah == 0)
break;
else
blah = 1;
myVar = blah;
}
Besides, even if we would take a kind of iterative kind of thing like "map"
what could break and continue possibly mean in that context?
> It has nothing to do with tail recursion.
Like my example above, I can only thing of example involving typical
do-something-while-not-hitting-an-exit-condition. Which is a very typical
recursion idiom. Given tail call optimization recursion is just as usefull,
if not more so, than typical java iteration idioms.
I just feel like long returns adds complexity and risks to solve a problem
that possibly is solved better in other ways.
BR,
John
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