From Expressions in “The Swift Programming Language” (emphasis added): Closure Expression … A closure expression can explicitly specify the values that it captures from the surrounding scope using a capture list. A capture list is written as a comma separated list surrounded by square brackets, before the list of parameters. If you use a capture … Read more
This is currently possible in environments with Proxies. That would be node > 0.6 run as node –harmony_proxies or >0.7 with node –harmony. Chromium Canary (not sure if it’s out of that yet) in about:flags at the bottom, experimental javascript. Firefox has had it for a while with no flags. So this probably won’t work … Read more
Not directly, but some workarounds are possible. Take a look at the following example. /// Target-Action helper. final class Action: NSObject { private let _action: () -> () init(action: @escaping () -> ()) { _action = action super.init() } @objc func action() { _action() } } let action1 = Action { print(“action1 triggered”) } let … Read more
Closure on closures Objects are data with methods attached, closures are functions with data attached. def make_counter(): i = 0 def counter(): # counter() is a closure nonlocal i i += 1 return i return counter c1 = make_counter() c2 = make_counter() print (c1(), c1(), c2(), c2()) # -> 1 2 1 2
Use a “closure”: $(edit_link).click(function(){ return changeViewMode(myvar); }); This creates an anonymous temporary function wrapper that knows about the parameter and passes it to the actual callback implementation.
Compare this, without using nonlocal: x = 0 def outer(): x = 1 def inner(): x = 2 print(“inner:”, x) inner() print(“outer:”, x) outer() print(“global:”, x) # inner: 2 # outer: 1 # global: 0 To this, using nonlocal, where inner()‘s x is now also outer()‘s x: x = 0 def outer(): x = 1 … Read more
You can replace target-action with a closure by adding a helper closure wrapper (ClosureSleeve) and adding it as an associated object to the control so it gets retained. This is a similar solution to the one in n13‘s answer. But I find it simpler and more elegant. The closure is invoked more directly and the … Read more
Yeah, the Groovy parser does not accept Java 8 Lambdas (not closures). You can use a closure in place of it (assuming you’re on Groovy 2.3.*) ie: Person.findAll().stream().filter( { e -> e.age > 20 } ) edit: Groovy 3.0+ will accept lambda format
If the closure is not owned by the class you do not have to use [weak self]. In the case of in-line closures the closure is not owned by the class but by the scope it is in and will be released when the scope is left. If the closure is passed in it may … Read more
Using FFCALL, #include <callback.h> #include <stdio.h> static void incrementer_(int *in) { ++*in; } static void emitter_(int *in) { printf(“%d\n”, *in); } int main() { int in1 = 10, in2 = 20; int (*incrementer1)() = alloc_callback(&incrementer_, &in1); int (*emitter1)() = alloc_callback(&emitter_, &in1); int (*incrementer2)() = alloc_callback(&incrementer_, &in2); int (*emitter2)() = alloc_callback(&emitter_, &in2); incrementer1(); incrementer2(); emitter1(); emitter2(); … Read more