As named right reference is left variable. I don't know what's the sense of allowing declare right reference in practice like following code snippet.
Object &&ro = std::move(lo);
Related
In V8 at least, in the debugger, you see local, script and global categorizing the variables.
I got a reference to global. All you do for that is set this on entry to a property to use later if need be.
However, I can't find how to save a reference to the script object. I think it exists because that's what the debugger is looping through in the watch window.
Before ES6, All declarations outside a function (and function declaration themselves) were properties of global object. After ES6, There are two kinds of global records:
Object record- Same as ES5.
Function declarations
Function generators
Variable assignments var
Declarative record - New
let, const, class, etc
Those in the declarative record are not accessible from the global "object", though they are globals themselves. They are accessible from the script, but the object/internal data structure holding the declarative records itself is not accessible or enumerable from inside the script. This declarative record is shown in v8 debugger as properties of script object.
References:
Global environment records
Related Answers:
ES6- What about introspection
Do let statements create properties on the global object
Let's say in Java, I have class CryptoFormat, which has a static method named getLegacyFormat(). When I want to use the method, I just need to call CryptoFormat.getLegacyFormat(). This is clear because I know where the method comes from.
In Go, there is no static method. I don't really want to just make a file called crypto_format.go and define the method there. The reason is that whenever I need the method, I just call GetLegacyFormat(), which doesn't contain the context where the method comes from.
I could think of two ways to solve the problem:
Make a separate package named cryptoformat, and define the method as a global function in the package. This way, I need to make a new package for just few methods. Also, whenever I need static methods like this, I have to define new packages.
Define a struct named cryptoFormat containing method GetLegacyFormat(). Also, define a global public variable named CryptoFormat, which points to an instance of struct cryptoFormat. This way, I can call CryptoFormat.GetLegacyFormat() when I need the method.
I am not sure which one is better, or whether there is better way.
I would say option 1 you mention is the more idiomatic way to define such functions, if they don't need any state that would warrant to tie them to an underlying struct.
If there is some state you'd like to have as context for the function, then option 2 would be the way to go.
Note that in Go, functions are "first class citizens", so you don't have Java's constraints of needing to define a class for static methods.
And yes, if you want a separate namespace you'd need to define separate packages (just as in Java you'd need to define separate classes and/or packages).
If you want your implementation to be idiomatic, I'd suggest you take a look at Go's standard libraries (pick a few packages and explore how they implement their functions) to get a better feeling of the usual ways to structure this.
whenever I need the method, I just call GetLegacyFormat(), which doesn't contain the context where the method comes from.
So add context to the function name.
GetLegacyCryptoFormat()
I have 10 different test cases .I want to create different objects of SwfEdit, SwfButton etc just once say in function and then use those in different actions in QTP.
I tried creating a function and linked it to a test case,however it did not work.
So I am not sure what could be correct way to link all these objects across all the test cases.
If you insist on creating your objects in code instead of using the object repository, you'll need to store those objects in some type of global variable. A basic example might be for a function library:
' Declare your global variable to hold the object
Public MyObject
' Create your object from a function
Public Sub InitializeGlobalObject()
' Use Descriptive Programing to create your object
Set MyObject = Window("title:=something").Button("index:=0")
End Sub
This will allow you to create the object once and then refer to it by the variable
' Click the button
MyObject.Click
You may run into issues caching an object like this because it will tend to hold on to the last screen object that it matches, whereas the object repository will refresh the screen object each time you call it. You may need to call the 'Refresh' method on your object before you use it for the first time after it is displayed on the screen.
You should use object repository to add objects first if you are not intending to use descriptive language.
You should spy on each object and then add it.
So I've created a class in boo that has three properties, Name as string, required as bool, read as bool.
Then Im going to create a method(SetDefault) that goes through the array of this type and sets all required properties back to true, and read back to false. Actually now that I think about it, Im not sure if it makes sense to have that as a method of the class. Doesn't matter.
Bottom line is Im declaring an array of this class type i've created.
testvar as (MyAttribute) = array(MyAttribute,10)
Once I've declared my array of this class, Im unable to reference any of the properties by using...
testvar(0).Name
The error is "It is not possible to invoke an expression of type (MyAttribute)"
I assume to use an array because they're all going to be the same data type. Is an array to correct type to use and if so what am I doing wrong?
Try using square brackets for array member access i.e. testvar[0].Name.
Recently i was reading "Cocoa Design Patterns". When talking about KVC, it said "KVC check if an accessor named -<key> or -get<Key> exists first, if not, it will try instance variable named <key> or _<key>".
Can obj-c runtime check whether an instance variable exist? I think it can only be done in compile time...
Any answers are appreciated ^_^
It can indeed. The relevant documentation for this is the Objective-C Runtime Reference; specifically, class_getInstanceVariable. The part the documentation leaves out is that that function returns NULL when instances of the class have no such variable.
KVC, presumably, passes the object's class and the candidate variable names to that function, and the first name for which the runtime comes up with an Ivar is the one it uses.