In the Pact language reference entry on namespaces, the text is clear that on public blockchains modules and interfaces must be defined within namespaces, and namespaces must be globally-unique.
Namespace declarations provide a unique prefix for modules and interfaces defined within the namespace scope. Namespaces are handled differently in public and private blockchain contexts: in private they are freely definable, and the root namespace (ie, not using a namespace at all) is available for user code. In public blockchains, users are not allowed to use the root namespace (which is reserved for built-in contracts like the coin contract) and must define code within a namespace, which may or may not be definable (ie, users might be restricted to “user” namespaces).
If I am writing a smart contract and need to define a namespace, is there any way for me to verify whether my namespace is unique?
Use (list-modules) to get a list of existing modules with their full namespace name. You can also list them from Chainweaver.
Please note that you cannot create the namespace on testnet or mainnet without it being assigned to you by Kadena. If you want to deploy in a public space without having to obtain a namespace use the existing namespace free or user.
Related
Using the instructions from http://www.milosev.com/98-c/wpf/373-autofac-and-prism-together#dependencyInjection I tried to setup my module's dependencies (eg. ViewModel requires some IServices to be constructed). The only thing I haven't used is that MEF thing but as far as I understood it is something alternative to Unity or Autofac.
I couldn't find any proper place to put the registration of types that are specific to my Module. Temporarily I use static method from my module class that is called from Bootstrapper's ConfigureContainerBuilder()
protected override void ConfigureContainerBuilder(ContainerBuilder containerBuilder)
{
base.ConfigureContainerBuilder(containerBuilder);
RoomSimulatorModule.InitializeDependencies(containerBuilder);
}
But it is called before my Module is initialised. Is there any way to add those types during module registration? Or due to the way Autofac constructs the container I can't register new types?
What is the meaning of public, protected, and private on class diagrams?
These are access modifiers. See the below:
https://en.wikipedia.org/wiki/Access_modifiers
Basically, "public" means that the item in question is available to anyone who has access to the object, "protected" means that it's available to the object itself and any subclasses, and "private" means it can be accessed only within the class itself. Some languages also add additional keywords, such as "internal" in C# (which basically means that it's available to any class in the same namespace; usually you use this if there's some class you use internally to your DLL that you don't want other people to use).
I am writing verification IP for some interface and facing with one interesting item, which I think is somehow basic for OOP.
So in my driver I have functions e.g. configMaster, which is DUT specific. And VIP user may want to override that function. Now I want to provide mechanism for user to do that.
I think the best way of overriding the VIP driver class functions would be following
User extends the driver class
In the extended class user redefines the driver methods that he wants. If there are several methods that user doesn’t want to override that’s fine.
Using factory override method user overrides the driver class with the
extended user_driver class
The thing I don’t like here that user each time running the simulation should specify the factory override command.
Could you please share your opinion is this right way to do? Are there other ways?
Thanks
Hayk
Step 3 is not always mandatory . After overriding the class the user can directly use the derived class in his TB. This will mostly be the case if the TB is being built afresh or the user is integrating this IP as a new component into an existing TB.
In case the VIP was already present in a TB and you are now providing new set of functions to the user to override or the user itself want to use the override mechanism preferring to instantiate the base class provided by the VIP and use the override mechanism later , user can use the set_type_override_by_type function .
The function can be embedded into a base test and all the derived test will implicitly use the use vip class derived by the user without the need to specify it explicitly in the command line for each test case.
There are 4 flavor to the type override function .
http://www.testbench.in/UT_06_UVM_FACTORY.html
The function can also be used in a base env too , the user has to ensure that the type override function is called before the class is create for the override mechanism to take effect.
Does anybody knows why BlockData class doesn't directly implement IContent?
I know that during BlockData is being retrieve from database, proxy created by Castle implements IContent.
If StackOverflow isn't suitable place for this kind of a question, please move it.
Johan Björnfot at EPiServer explains some of the details in this post.
Excerpt:
"In previous versions of CMS was pages (PageData) the only content type that the content repository (traditionally DataFactory) handled. In CMS7 this has changed so now content repository (IContentRepository) handles IContent instances. This means that the requirement for a .NET type to be possible to save/load from content repository is that it implements the interface EPiServer.Core.IContent.
There are some implementations of IContent built into CMS like PageData and ContentFolder (used to group shared block instances) and it is also possible to register custom IContent implementations.If you look at BlockData though you will notice that it doesn’t implement IContent, how is then shared block instances handled?
The answer is that during runtime when a shared block instance is created (e.g. through a call to IContentRepository.GetDefault where T is a type inheriting from BlockData) the CMS will create a new .NET type inheriting T using a technic called mixin where the new generated subclass will implement some extra interfaces (including IContent)."
BlockData does implement IContent as it is intended to work both when added to another content item such as a PageData instance (a.k.a. Local Block), and as a standalone instance (a.k.a.Shared Block). In latter case the interface is added by using a mix-in though Castle Windsor so that it can be referenced.
The decision for this construct was based on wanting to be able to use the same rendering templates regardless if a block is local or shared. Therefor the choice stood between having a large number of empty properties on local blocks or the current solution using mixins. Both options were tested and mixins was selected as the preferred solution even though it's not a perfect one.
BlockData "does implement IContent", just do:
var myContent = (IContent)myBlock;
But, if you're by any chance handling a Block which itself is a property (not a ContentReference), that cast will throw an exception.
This will be true for 100% of all cases (... using Math.Round).
I've read the entire Swift book, and watched all the WWDC videos (all of which I heartily recommend). One thing I'm worried about is data encapsulation.
Consider the following (entirely contrived) example:
class Stack<T>
{
var items : T[] = []
func push( newItem: T ) {
items.insert( newItem, atIndex: 0 )
}
func pop() -> T? {
if items.count == 0 {
return nil;
}
return items.removeAtIndex( 0 );
}
}
This class implements a stack, and implements it using an Array. Problem is, items (like all properties in Swift) is public, so nothing is preventing anyone from directly accessing (or even mutating) it separate from the public API. As a curmudgeonly old C++ guy, this makes me very grumpy.
I see people bemoaning the lack of access modifiers, and while I agree they would directly address the issue (and I hear rumors that they might be implemented Soon (TM) ), I wonder what some strategies for data hiding would be in their absence.
Have I missed something, or is this simply an omission in the language?
It's simply missing at the moment. Greg Parker has explicitly stated (in this dev forums thread) that visibility modifiers are coming.
Given that there aren't headers, the standard Objective-C tricks won't work, and I can't think of another trick to limit visibility that doesn't involve lots of bending over backwards. Since the language feature has been promised I'm not sure it's worth any big investment.
On the bright side since this feature is in flux, now is a great time to file a radar and influence how it turns out.
Updated answer for future reference.
From Apple's documentation:
Access Levels
Swift provides three different access levels for
entities within your code. These access levels are relative to the
source file in which an entity is defined, and also relative to the
module that source file belongs to.
Public access enables entities to
be used within any source file from their defining module, and also in
a source file from another module that imports the defining module.
You typically use public access when specifying the public interface
to a framework.
Internal access enables entities to be used within any
source file from their defining module, but not in any source file
outside of that module. You typically use internal access when
defining an app’s or a framework’s internal structure.
Private access
restricts the use of an entity to its own defining source file. Use
private access to hide the implementation details of a specific piece
of functionality. Public access is the highest (least restrictive)
access level and private access is the lowest (or most restrictive)
access level.
As a matter of fact I was delighted Swift finally adopted static typing so conforming to the theory for code with optimal OO properties, still the fall of the headers breaks the very meniang of Object Orienting programming, namely encapsulation. A way out would be like for Eiffel to automaticaly extract the headers but without specifying which are the public interfaces and which the private ones, it would be wortheless. I am really lambasted at this move of Apple's.