constants

问题 I have a question about types of constants which are restricted to certain values and how you accomplish that in Go. Say I create a type unary which has two constant values Positive(1) and Negative(-1) and I want to restrict the user of that type ( unary ) from creating other values of type unary . Do I achieve this by creating a package and making the values Positive and Negative visible and making the type unary restricted to the containing package? See code below for example package unary

问题 I have a question about types of constants which are restricted to certain values and how you accomplish that in Go. Say I create a type unary which has two constant values Positive(1) and Negative(-1) and I want to restrict the user of that type ( unary ) from creating other values of type unary . Do I achieve this by creating a package and making the values Positive and Negative visible and making the type unary restricted to the containing package? See code below for example package unary

问题 I'm not sure which of both are better to define constants. A struct or a enum. A struct will be copied every time i use it or not? When i think about a struct with static let constants it makes no sense that it will copied all the time, in my opinion. But if it won't copied then it doesn't matter what I take? What advantages does the choice of a struct or enum? Francisco say use Struct's. Ray Wunderlich say use Enum's. But I lack the justification. 回答1: Both structs and enumerations work. As

问题 I'm not sure which of both are better to define constants. A struct or a enum. A struct will be copied every time i use it or not? When i think about a struct with static let constants it makes no sense that it will copied all the time, in my opinion. But if it won't copied then it doesn't matter what I take? What advantages does the choice of a struct or enum? Francisco say use Struct's. Ray Wunderlich say use Enum's. But I lack the justification. 回答1: Both structs and enumerations work. As

问题 I followed the documentation to put the constants in the lib/constants.js file. Question : How to access these constants in my client side html and js files? 回答1: You will need to make them global variables in order for other files to see them. JavaScript /lib/constants.js THE_ANSWER = 42; // note the lack of var /client/some-other-file.js console.log(THE_ANSWER); CoffeeScript /lib/constants.coffee @THE_ANSWER = 42 /client/some-other-file.coffee console.log THE_ANSWER 回答2: Variables in Meteor

问题 What is the difference between const and readonly in C#? When would you use one over the other? 回答1: Apart from the apparent difference of having to declare the value at the time of a definition for a const VS readonly values can be computed dynamically but need to be assigned before the constructor exits.. after that it is frozen. 'const's are implicitly static . You use a ClassName.ConstantName notation to access them. There is a subtle difference. Consider a class defined in AssemblyA .

问题 I have only PHP 5.4 available at my current hoster and I always get errors with class constants in my code. Apparently, it's not allowed to define array constants. I changed the constant to a static variable to make it work. Now I get this syntax error: syntax error, unexpected '.', expecting ']' I try to define strings that consist of concatenated constants. public static $arr = [KEY_ONE => "string " . MyClass::CONSTANT . " string"] is this possible or do all constants have to be static

问题 The following declaration: const(string[char]) AA1 = [ 'a' : "fkclopel", 'b' : "poehfftw" ]; void main(string args[]){} gives me: C:...\temp_0186F968.d(1,27): Error: non-constant expression ['a':"fkclopel", 'b':"poehfftw"] while it would work with other type kinds. 回答1: You can initialize associative array constants inside a module constructor: const /+ or immutable +/ (string [char]) AA1; static this () { AA1 = [ 'a' : "fkclopel", 'b' : "poehfftw" ]; } import std.stdio; void main () {writeln

问题 I have tried putting the variables in the string but it reads as blank when I run the program. Here is an example of what I'm working with: use constant { #list will contain more errors ERROR_SW => { errorCode => 727, message => "Not able to ping switch $switch_ip in $timeout seconds", fatal => 1, web_page => 'http://www.errorsolution.com/727', } }; sub error_post { my ($error) = @_; print($error->{message}); } error_post(ERROR_SW); I simply want to post the error with the variable values

问题 I would like to get the address of an string-constant in C. char * const MYCONST = "StringString"; As far as I know consts are "saved" in the Text/Code Segment of the memory. When I try to get the address of the first element in MYCONSt: printf("%p\n",&(MYCONST)); As result I get 0x7fff15342e28, which is in the stack and not in the Text/Code segement. Can anybody please help me get the address of a string-constant in C? //edit I can't find the correct answer so far: When I write char * const