closures

I found this page stating that Java 8 support for Juno is deffered, but I can't find more information how soon people can exspect to be able to write first closures in Eclipse and get productive with that stuff. Has someone got insight how long we still have to wait? The Java7 features were in 3.7 really quickly, that's why it's kind of odd that this task is deferred. Any comments, ideas? Or maybe even a good workaround? One of the key reasons that Java 8 support was deferred is that Java 8 will be available after Eclipse Juno is released. A major release of Eclipse couldn't be shipped with

I'm working on a bit of code where I'm attempting to hide some private variables inside closures. The thing is the environment is fairly constrained in terms of memory, so I'm also concerned with keeping the overall footprint of the classes low. What is the impact of using closures to hide private instance variables and methods when compared to just making all methods and variables on an object public? Would an instance of the one using closures take up more memory than an instance that did not use closures? If so, how much more memory would I expect to use? my code would look like this

I'm trying to avoid repeating myself by using a closure in the following code: fn add_raw(&mut self, pair: RawLinkPair) { let convert = |raw: &RawLink| { Link{ id: self.get_or_create(raw.name).id, flow: raw.flow, } }; println!("Hive received pair: {}", pair); let parent = convert(&pair.parent); let child = convert(&pair.child); self.link_concepts(parent, child); } That doesn't work. It gives me this error: hive.rs:64:9: 64:13 error: cannot borrow `*self` as mutable because previous closure requires unique access hive.rs:64 self.link_concepts(parent, child); ^~~~ hive.rs:55:23: 60:10 note:

I find the use of the C++0x closure perplexing. My initial report , and the subsequent one , have generated more confusion than explanations. Below I will show you troublesome examples, and I hope to find out why there is an undefined behavior in the code. All the pieces of the code pass the gcc 4.6.0 compiler without any warning. Program No. 1: It Works #include <iostream> int main(){ auto accumulator = [](int x) { return [=](int y) -> int { return x+y; }; }; auto ac=accumulator(1); std::cout << ac(1) << " " << ac(1) << " " << ac(1) << " " << std::endl; std::cout << ac(1) << " " << ac(1) << "

I'm a bit stumped on how to get this working, I've cut it down from the real thing. I wrote a trait: pub trait Renderable<F: Fn(&PropertyTags)> { fn set_property_changed_callback(&mut self, callback: Option<F>); } Which the 'child' parameter of add_child is restricted by and PropertyTags is just an enum. I've included mock implementations of the type of child to demonstrate my usage: pub struct Child<F: Fn(&PropertyTags)> { property_changed_callback: Option<F>, } impl<F: Fn(&PropertyTags)> Renderable<F> for Child<F> { fn set_property_changed_callback(&mut self, callback: Option<F>) { self

This question already has an answer here: Why do closures require an explicit `self` when they're all non-escaping by default in Swift 3? 2 answers I have a function which looks something like this: func test(closure: () -> ()) { let localClosure = { closure() } localClosure() } This is only an example and does not fully reflect the problem I encountered, obviously here I could have just called closure directly! It should be clear that in the above code, closure cannot escape. However, I get the error: Closure use of non-escaping parameter 'closure' may allow it to escape Now, if localClosure

Is this possible to add variable to callback scope? What I want to achieve is: ... Foo.prototype.bar = function(fn) { var baz = "baz!"; fn.call(this); } ... Foo.bar(function() { console.log(baz) // gives "baz!" }); I know I can pass baz variable as an argument or this but I'm interested in something like above. No, it's not possible. The only ways are the ones you pointed out: as an argument or in this . What about doing it this way: var Foo = function(){} Foo.prototype.handle = function(fn) { var baz = "baz !"; eval('(' + fn.toString() + ')();'); } var foo = new Foo; foo.handle(function (){

I'm trying to experiment with the Groovy closure recursion example from http://groovy.codehaus.org/JN2515-Closures . I saved the snippet in a file called recursionTest.groovy and loaded it in the shell, but I'm getting a "No signature of method error": // recursionTest.groovy def results = []; { a, b -> results << a a<10 && call(b, a+b) }(1,1) assert results == [1, 1, 2, 3, 5, 8, 13] groovy:000> load recursionTest.groovy ===> [] ERROR groovy.lang.MissingMethodException: No signature of method: java.lang.Boolean.call() is applicable for argument types: (groovysh_evaluate$_run_closure1) values: