I have the following function, but I can't seem to get the myVar variable into the inline function. What am I doing wrong here? What I would like to have happen is when I click on myMc, it should print myVar to the console ("hello computer").
function doSomething():Void
{
myVar = "hello computer";
myMc.onRelease = function(){
trace(myVar); //prints as "undefined"
}
}
ps. - I cannot declare myVar as a global or static variable because in the real code, I'm parsing XML and the myVar is constantly changing.
This is a scope issue - when you apply an onRelease function like this in as2, the scope of the function is the MovieClip you apply the function to, not the calling function.
Because you are using AS2 and MovieClip is dynamic, you can assign the variable to the MC directly:
function doSomething():Void
{
myMc.myVar = "hello computer";
myMc.onRelease = function(){
trace(this.myVar);
}
}
Try declaring myVar with the var keyword:
var myVar = "hello computer";
Related
I have an issue I can't solve regarding AHK. My code:
begin()
begin() {
Global Input
Gui, Add, Edit, vInput gInputChanged
}
InputChanged() {
MsgBox, Your input is %Input%
}
Simple enough, eh? However when InputChanged() is triggered the variable Input is never correct (it is always null).
Refer to Function Variables and Scope
Example:
Input := "Hello" ; Our Variable Defined outside of our Function
begin() ; Call the function passing no Variables
begin() {
Global Input
MsgBox, Global! Input = %Input%
InputChangedLocally(Input) ; Pass the Input variable which is 'Hello'
}
InputChangedLocally(Input) {
Input .= " World!" ; Change Local variable
MsgBox, Changed Locally %Input%
OnlyGlobalInput()
}
OnlyGlobalInput() {
Global Input
; Notice it is not 'Hello World!' even though we changed it above!
MsgBox, Global! Input = %Input%
InputNotPassedOrGlobal()
}
InputNotPassedOrGlobal() {
MsgBox, Your input is %Input% ; Blank as we never accessed any thing!
}
got the same problem, not figure out why this happen yet, but can use this workround
ControlGetText, TestCode2, Edit1,A
to get the input value
I want to parse and set a variable conditionally in Go at the global package level based on the value of of an ENV var, so that I don't have to check for it every time in a utility function (as the variable would be declared once at run time). For example, what I want to accomplish is (Go pseudo-code):
import (
"fmt"
"os"
"strconv"
)
// This works to read the value of MYVAR (=true/false)
var myvar string = os.Getenv("MYVAR")
// Apparently this is too much for Go
var myvarbool, _ = strconv.ParseBool(myvar)
// Utility function to check for value
func mycheck() {
if myvarbool {
fmt.Print("MYVAR is true")
}
}
This is a library package, so doesn't have a main() function to do this kind of setup, but I want to be able to use mycheck() in other functions in the library, and don't want to have to read and parse MYVAR every time mycheck() is called.
One way to accomplish what you're looking to do would be to process the environment variable in an init() function, so something like the following would work:
package main
import (
"fmt"
"os"
"strconv"
)
var (
myvar string = os.Getenv("MYVAR")
myvarbool bool
)
func init() {
myvarbool, _ = strconv.ParseBool(myvar)
}
// Utility function to check for value
func mycheck() {
if myvarbool {
fmt.Print("MYVAR is true")
}
}
Playground
I'm not sure what problem you had, your code from the OP is valid, also you can have it in one line like:
var myvarbool, _ = strconv.ParseBool(os.Getenv("MYVAR"))
playground
After actually thinking about this for a couple of minutes, I've realised I can just create a wrapper function to do the work, and call that instead (again, largely pseudo-code without extra checks):
var myenvbool bool = myenv("MYVAR")
func myenv(envvar string) bool {
myenvvalue := os.Getenv(envvar)
myenvbool, _ := strconv.ParseBool(myenvvalue)
return myenvbool
}
func checkenv() {
if myenvbool {
fmt.Print("myenvbool is true")
}
}
I'm building a Go library for an API that offers JSON or XML formatted data.
This API requires me to request a session_id every 15 minutes or so, and use that in calls. For example:
foo.com/api/[my-application-id]/getuserprofilejson/[username]/[session-id]
foo.com/api/[my-application-id]/getuserprofilexml/[username]/[session-id]
In my Go library, I'm trying to create a variable outside of the main() func and intend to ping it for a value for every API call. If that value is nil or empty, request a new session id and so on.
package apitest
import (
"fmt"
)
test := "This is a test."
func main() {
fmt.Println(test)
test = "Another value"
fmt.Println(test)
}
What is the idiomatic Go way to declare a globally-accessible variable, but not necesarilly a constant?
My test variable needs to:
Be accessible from anywhere within it's own package.
Be changeable
You need
var test = "This is a test"
:= only works in functions and the lower case 't' is so that it is only visible to the package (unexported).
A more thorough explanation
test1.go
package main
import "fmt"
// the variable takes the type of the initializer
var test = "testing"
// you could do:
// var test string = "testing"
// but that is not idiomatic GO
// Both types of instantiation shown above are supported in
// and outside of functions and function receivers
func main() {
// Inside a function you can declare the type and then assign the value
var newVal string
newVal = "Something Else"
// just infer the type
str := "Type can be inferred"
// To change the value of package level variables
fmt.Println(test)
changeTest(newVal)
fmt.Println(test)
changeTest(str)
fmt.Println(test)
}
test2.go
package main
func changeTest(newTest string) {
test = newTest
}
output
testing
Something Else
Type can be inferred
Alternatively, for more complex package initializations or to set up whatever state is required by the package GO provides an init function.
package main
import (
"fmt"
)
var test map[string]int
func init() {
test = make(map[string]int)
test["foo"] = 0
test["bar"] = 1
}
func main() {
fmt.Println(test) // prints map[foo:0 bar:1]
}
Init will be called before main is run.
If you accidentally use "Func" or "function" or "Function" instead of "func" you will also get:
non-declaration statement outside of function body
Posting this because I initially ended up here on my search to figure out what was wrong.
Short variable declarations i.e. :=, can ONLY be used within functions.
e.g.
func main() {
test := "this is a test"
// or
age := 35
}
Declarations outside a function you must make use of keywords like var, func, const e.t.c depending on what you want (in this case we're using var).
Declaring a variable outside a function makes it accessible within its package.
package apitest
import (
"fmt"
)
// note the value can be changed
var test string = "this is a test"
func main() {
fmt.Println(test)
test = "Another value"
fmt.Println(test)
}
Extra info
If you want the variable to be accessible both within and outside its package, the variable has to be capitalized e.g.
var Test string = "this is a test"
this will make it accessible from any package.
We can declare variables as below:
package main
import (
"fmt"
"time"
)
var test = "testing"
var currtime = "15:04:05"
var date = "02/01/2006"
func main() {
t := time.Now()
date := t.Format("02/01/2006")
currtime := t.Format("15:04:05")
fmt.Println(test) //Output: testing
fmt.Println(currtime)//Output: 16:44:53
fmt.Println(date) // Output: 29/08/2018
}
Outside a function, every statement begins with a keyword (var, func, and so on) and so the := construct is not available.
You can read more information here: https://tour.golang.org/basics/10
I got this error when I was trying to run Go app with function definition like this:
(u *UserService) func GetAllUsers() (string, error) {...} //Error code
The correct way of defining a function (receiver function) was:
func (u *UserService) GetAllUsers() (string, error) {...} //Working code
I use the following pattern in my JS:
var lib =
{
module_one:
{
init: function () {
...
}
},
module_two:
{
init: function () {
...
}
}
};
Question is, whats the best way to add:
(function ($) {
...
})(jQuery);
I tried to put it around the var lib, but that didnt work. To add it inside each function worked, but seems a bit messy..?
Is it possible to add it to the init: function($) somehow?
Quite new on jQuery, so if you have any other suggestions around this pattern, let me know :-)
Basically, you can do this:
(function() {
var global, lib, oldlib;
// We call this anonymous scoping function directly, so we know that
// within it, `this` is the JavaScript global object. Grab a
// local reference to it so we can use it within functions that get
// called via dotted notation and so have different `this` values.
global = this;
// Remember any value that already exists for the `lib` property
// of the global
oldlib = global.lib;
// Define our lib, assigning it to a local variable
lib = {
/* ...your stuff as usual, plus: */
noConflict: function() {
global.lib = oldlib;
return lib;
}
};
// Publish our lib externally on the global object
global.lib = lib;
})();
...which can then be used like this:
var alias = lib.noConflict();
Here's how that works:
We define a scoping function and then immediately call it.
Within the scoping function, we grab the this value as a variable called global. This will be the JavaScript global object because of the way we're calling the scoping function. (The global object on browsers is window, but there's no need to limit this to browsers, hence getting global this way).
The first thing we do is save any old value the lib property of the global object had, in a local variable in our scoping function called oldlib.
We set up our new value for lib.
Our noConflict function restores the earlier value of the lib property, and returns our lib reference so someone can use it as an alias.
BTW, when you use a scoping function, you can also switch over to using named functions rather than anonymous ones, which has several benefits. Here's the above updated to use a named function for noConflict.
(function() {
var global, lib, oldlib;
// We call this anonymous scoping function directly, so we know that
// within it, `this` is the JavaScript global object. Grab a
// local reference to it so we can use it within functions that get
// called via dotted notation and so have different `this` values.
global = this;
// Remember any value that already exists for the `lib` property
// of the global
oldlib = global.lib;
// Define the functions for our lib. Because they're defined
// within our scoping function, they're completely private
function lib_noConflict() {
global.lib = oldlib;
return lib;
}
// Define our lib, publishing the functions we want to be public
lib = {
/* ...your stuff as usual, plus: */
noConflict: lib_noConflict
};
// Publish our lib externally on the global object
global.lib = lib;
})();
How can i call a function form a variable.
var upfunction = init;
//or
var upfunction = init();
I have tried the above code and it does not work. I want to be able to call that variable from a keypress and change the variables function. For example.
function init(){
//Do whatever
}
function init2(){
//Do another thing
}
var upfunction = init();
if (Key.getCode() == Key.UP)
{
upfunction;
}
Then later doing
upfunction = init2();
That way i could change the function without having much code. Sorry if this is a noob question but all i do is copy and paste code i have found.
You're almost right with what you've got... just remember that to call a function you need to include the brackets afterwards: 'upFuntion();'. Brackets are also needed when defining the function. The brackets will contain any function parameters.
But to refer to the function (such as when assigning it to a variable) you don't use the brackets: 'upFunction = init;'
So your example would look like this:
function init1():Void {
trace("hello this is init1");
}
function init2():Void {
trace("hey, this is init2");
}
var upFunction:Function = init1;//type declaration is optional but recommended
upFunction();// hello this is init1
upFunction = init2;
upFunction();//hey, this is init2