closures

问题 is it possible to load a closure's code from a string (that may come from a file) in Groovy ? 回答1: Did you mean something like this? groovy:000> sh = new GroovyShell() ===> groovy.lang.GroovyShell@1d6dba0a groovy:000> closure = sh.evaluate("{it -> println it}") ===> Script1$_run_closure1@59c958af groovy:000> closure(1) 1 ===> null groovy:000> [1,2,3,4].each { closure(it) } 1 2 3 4 ===> [1, 2, 3, 4] groovy:000> 回答2: This should work, not sure if it's the most elegant solution: ClassLoader

问题 is it possible to load a closure's code from a string (that may come from a file) in Groovy ? 回答1: Did you mean something like this? groovy:000> sh = new GroovyShell() ===> groovy.lang.GroovyShell@1d6dba0a groovy:000> closure = sh.evaluate("{it -> println it}") ===> Script1$_run_closure1@59c958af groovy:000> closure(1) 1 ===> null groovy:000> [1,2,3,4].each { closure(it) } 1 2 3 4 ===> [1, 2, 3, 4] groovy:000> 回答2: This should work, not sure if it's the most elegant solution: ClassLoader

问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 4 years ago . I am been to ios development for few months and eager to implement new things in my programming pattern. Now i am learning closures and knew little things about its syntax,knew it can be used instead of delegate for callbacks. As well as implemented it in some UIViewAnimation and

问题 If I have a closure passed to a function like this: someFunctionWithTrailingClosure { [weak self] in anotherFunctionWithTrailingClosure { [weak self] in self?.doSomething() } } If I declare self as [weak self] in someFunctionWithTrailingClosure 's capture list without redeclaring it as weak again in the capture list of anotherFunctionWithTrailingClosure self is already becoming an Optional type but is it also becoming a weak reference as well? Thanks! 回答1: The [weak self] in

问题 If I have a closure passed to a function like this: someFunctionWithTrailingClosure { [weak self] in anotherFunctionWithTrailingClosure { [weak self] in self?.doSomething() } } If I declare self as [weak self] in someFunctionWithTrailingClosure 's capture list without redeclaring it as weak again in the capture list of anotherFunctionWithTrailingClosure self is already becoming an Optional type but is it also becoming a weak reference as well? Thanks! 回答1: The [weak self] in

问题 This question already has answers here : Why are only final variables accessible in anonymous class? (13 answers) Closed 6 years ago . This question was migrated from Software Engineering Stack Exchange because it can be answered on Stack Overflow. Migrated 6 years ago . I'm reading about anonymous classes in java and it says you can access the methods of the enclosing class, but not the local variables. Why is it like this? I'm talking about this: EDIT: The older example was incorrect not

问题 With the following code I am able to take values out of an object and add them to the global namespace. This is defined in the expose function function expose(key, obj){ window[key] = obj[key]; } I can have been using it to take functions I use a lot out of libraries, such as map from underscore // before map //undefined _.map // have to use like this expose('map', _) // after map // function I would like modify expose so that it does the same job but only in a closure. How to solve this is

问题 I'm trying to set a variable that is outside a closure inside that closure, but it doesn't end up getting set in the end. However, the value that I'm setting the variable to is being printed to the console. Also, right after setting the return variable and printing it itself, the correct value is being printed to the console. The problem arises when I return the variable; its value stays the same as the value at initialization. Here is some psuedo-code: let str: String = { var ret: String =

问题 My function throw me with the local variable 'pt' referenced before assignment error: Traceback (most recent call last): File "/home/solesschong/Workspace/PenPal/python/main.py", line 126, in callback ind = (i+pt) % n UnboundLocalError: local variable 'pt' referenced before assignment the code is as follows def get_audio_callback(pt): def callback(in_data, frame_count, time_info, status): for i in range(frame_count): ind = (i+pt) % n return (a, b) return callback and in global scope, pt = 0

问题 I want to hook up a UIButton to a piece of code – from what I have found, the preferred method to do this in Swift is still to use the addTarget(target: AnyObject?, action: Selector, forControlEvents: UIControlEvents) function. This uses the Selector construct presumably for backwards compatibility with Obj-C libraries. I think I understand the reason for @selector in Obj-C – being able to refer to a method since in Obj-C methods are not first-class values. In Swift though, functions are