scope

问题 Other than self.class.send :method, args... , of course. I'd like to make a rather complex method available at both the class and instance level without duplicating the code. UPDATE: @Jonathan Branam: that was my assumption, but I wanted to make sure nobody else had found a way around. Visibility in Ruby is very different from that in Java. You're also quite right that private doesn't work on class methods, though this will declare a private class method: class Foo class <<self private def

问题 I have a linux bash script with a function: myfunctiona () { local MYVAR1="one" local MYVAR2="two" echo $MYVAR1 # The line beneath is the line in question! local MYVAR1=$MYVAR1$MYVAR2 } When I want to give the LOCAL variable MYVAR1 in the function myfunctiona a new value, do I have to write local MYVAR1=$MYVAR1$MYVAR2 or can I also write MYVAR1=$MYVAR1$MYVAR2 With the second line without "local" do I create a global variable with the same name? 回答1: Once you've defined a local variable you

问题 I am using cygwin. What this script does is load the iphone pics that I have loaded into a directory on the desktop. It opens it up in image viewer, to let me take a look at the picture. system("cygstart $dirname/$oldfile") ; Then it gives me the option to rename the picture. It is throwing errors though, and not renaming the picture. Use of uninitialized value $oldfile in concatenation (.) or string at ./rename_image.pl line 29, <STDIN> line 6. oldfile is a global varaible, the functions

问题 I want to pass data queried in my model to the controller, to do so I am using return $data. Then in the controller I use $this->load->view('my_view', $data); From my understanding var_dump($data); in the view should show me the results from the query... This is not the case. I am getting "undefined variable data" and NULL from the var_dump($data); . Here is my model: <?php if ( ! defined('BASEPATH')) exit('No direct script access allowed'); class Manage_accounts_model extends CI_Model {

问题 I'm trying to execute a piece of code within an empty isolated execution context in JavaScript. In the below sample, I'm trying isolate isolated execution scope. What I want to do is to execute a function in context where no global variables are in. (function() { 'use strict'; var scope = Object.create(null); var isolated = function() { 'use strict'; console.log(document); // Trying to get undefined // but traces `document`. }; isolated.call(scope); })(); I thought it was simple to nullify

问题 What exactly is the local scope defined outside of a function? Consider the following code: <cfscript> local.madVar2 = "Local scope variable"; function madness() { var madVar = "madness variable"; madVar2 = "madness two variable"; writeOutput("local: <BR>"); writeDump(local); writeOutput("========================================= <BR>"); writeOutput("local.madVar2: <BR>"); writeDump(local.madVar2); writeOutput("<BR>========================================= <BR>"); writeOutput("madVar2: <BR>")

问题 In both Java and C# it is possible to invoke a private method via reflection (as shown below). Why is this allowed? What are the ramifications of doing this? Should it be taken away in a future version of the language? Do other languages/platforms allow this?If I have this class in both Java and C# Here is the example public class Foo { private void say() { WriteToConsoleMethod("Hello reflected world"); } } where WriteToConsole() is language specific, then I can run the following to call the

问题 Is there any kind of performance or other difference between following two cases of accessing a global variable in a closure: Case 1: $closure = function() use ($global_variable) { // Use $global_variable to do something. } Case 2: $closure = function() { global $global_variable; // Use $global_variable to do something. } 回答1: There is an important difference between your two examples: $global_variable = 1; $closure = function() use ($global_variable) { return $global_variable; }; $closure2 =

问题 I am writing my angularjs directive with definition like: return { restrict: 'EA', link: link, scope: true, transclude: true, replace: true, controller: controller, template: '<div class="wizard">' + '<div ng-transclude></div>' + '</div>' }; I notice two scopes was created: < Scope (003) --- parent scope of directive < Scope (004) --- controller scope of directive which I think is child scope created by 'scope=true'. all my functions, properites defined in controller show up in this scope <

问题 I have a multi-machine Vagrantfile setting up a 5 node environment. I've been looking around to see what levels of control you have over the order of provisioning, but it's pretty limited: https://docs.vagrantup.com/v2/multi-machine/ I want to provision 5 nodes, then go back to the first node, and run other provisioning steps there. What I mean is that you have a Vagrantfile like this: Vagrant.configure('2') do |config| config.vm.provision some stuff config.vm.define 'node1' do |node1| node1