scope

问题 What is POI? I have seen this term being used several times in context of C++ Templates. What does it mean? 回答1: POI means Point Of Instantiation. From C++ Templates : The Complete Guide 10.3.2 Points of Instantiation A point of instantiation (POI) is created when a code construct refers to a template specialization in such a way that the definition of the corresponding template needs to be instantiated to create that specialization. The POI is a point in the source where the substituted

问题 MY directories are as follows. public_html/ sw/ The "sw/" is where I want to put all service workers, but then have those service workers with a scope to all the files in "public_html/". JS <script> if ('serviceWorker' in navigator) { navigator.serviceWorker.register('sw/notifications.js', { scope: '../sw/' }).then(function(reg) { // registration worked console.log('Registration succeeded. Scope is ' + reg.scope); }).catch(function(error) { // registration failed console.log('Registration

问题 when a variable is initialize both in local scope as well as global scope how can we use global scope without using this keyword in the same class? 回答1: class MyClass{ int i;//1 public void myMethod(){ i = 10;//referring to 1 } public void myMethod(int i){//2 i = 10;//referring to 2 this.i = 10 //refering to 1 } } Also See : Shadowing Declarations what-is-variable-shadowing-used-for-in-a-java-class 回答2: If you do not use this it will always be the local variable. 回答3: It is impossible without

问题 I have this code for example. #include <stdlib.h> #include <stdio.h> #define array_size 3 typedef struct { int array[array_size]; } TEST; void printout(TEST *p, int element) { printf("element: %i\n", p->array[element]); } int main(void) { TEST *p; p = malloc(sizeof(TEST)); p->array[0] = 5; printout(p, 0); return 0; } But I'd like to assign "array_size" based on user input. If I try to do so, the compiler says "variably modified ‘array_size’ at file scope" . So, am I right that the only way to

问题 Apologies if this question has been asked already, but suppose we have this code (I've run it with Mono 2.10.2 and compiled with gmcs 2.10.2.0): using System; public class App { public static void Main(string[] args) { Func<string> f = null; var strs = new string[]{ "foo", "bar", "zar" }; foreach (var str in strs) { if ("foo".Equals(str)) f = () => str; } Console.WriteLine(f()); // [1]: Prints 'zar' foreach (var str in strs) { var localStr = str; if ("foo".Equals(str)) f = () => localStr; }

问题 My application has a button to execute a python script dynamically using execfile . If I define a function inside the script (eg. spam() ) and try to use that function inside another function (eg. eggs() ), I get this error: NameError: global name 'spam' is not defined What is the correct way to call the spam() function from within eggs() ? #mainprogram.py class mainprogram(): def runme(self): execfile("myscript.py") >>> this = mainprogram() >>> this.runme() # myscript.py def spam(): print

问题 Problem: How to define local variables within a scope in a r-code. Example: In C++ the following example defines a scope, and variables declared within the scope are undefined in outside code. { vector V1 = getVector(1); vector V1(= getVector(2); double P = inner_product(V1, V2); print(P); } // the variable V1, V2, P are undefined here! Note: This code is only to illustrate the idea. This practice has the advantages of: Keeping the global namespace clean; simplifying code; removing

问题 So I have a class, which I'm using as a local namespace. I have some static functions in the class, but they can't access the class scope variables. Why is this? class Foo: foo_string = "I am a foo" @staticmethod def foo(): print foo_string >>> Foo.foo() [Stack Trace] NameError: global name 'foo_string' is not defined Any thoughts? 回答1: Python doesn't let class variables fall into scope this way, there are two ways to do this, the first is to use a class method: @classmethod def foo(cls):

问题 So I have this problem where I have to figure out the output using two different scoping rules. I know the output using lexical scoping is a=3 and b=1 , but I am having hard time figure out the output using dynamic scoping. Note:the code example that follows uses C syntax, but let's just treat it as pseudo-code. int a,b; int p() { int a, p; a = 0; b = 1; p = 2; return p; } void print() { printf("%d\n%d\n",a,b); } void q () { int b; a = 3; b = 4; print(); } main() { a = p(); q(); } Here is

问题 I was going through the Difference between var and let documentation example and was testing that when an undeclared variable is invoked, the global scope automatically provides a declaration for it (that's why the following snippet does not throw an error in any of the variables): x = 3; console.log(x); (function() { y=x+39; })() console.log(y); However, when one variable is declared with let after the assignment in the same global scope: x=3; let x = 42; console.log(x); One of the following