I've read over internet some relevant information that in fact .Net provides possibility to create defined new dynamic type at runtime. First i thought its great news because my current application got hard-coded enum type defined in class. What my thought was i could create that enum usinf reflection and create his enum values from XML. Unfortunetly i tried to find some good tutorial but cannot find something could explain me enough how to do that. Can you give me either some good sample or redirect me to somwhere where i can obtain some knowledge how could i achieve that?
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I know some of this, but not all of it. Most notably, I am aware of TypeDescription.Generic.Builder but I have a very specific question about it.
Suppose I want to build Supplier<? extends Frob<X>>.
Suppose further that all I know I have is a TypeDefinition for the parameter, but I don't know what it represents (in the example above it would represent Frob<X>). That is, I don't know whether the TypeDefinition I have is a class, a parameterized type, a generic array type, a type variable, a wildcard, or anything else; I just know it's a TypeDefinition.
Obviously if I wanted to make Supplier<Frob<X>>, I could just do:
TypeDescription.Generic.Builder.parameterizedType(TypeDescription.ForLoadedType.of(Supplier.class),
myTypeDefinition)
.build();
…assuming I haven't made any typos in the snippet above.
How can I make an upper-bounded wildcard TypeDefinition out of an existing TypeDefinition suitable for supplying as the "parameterized" part of a parameterized type build? Is there an obvious recipe I'm overlooking, or is this a gap in the builder's DSL?
(I'm aware of the asWildcardUpperBound() method on TypeDescription.Generic.Builder, but that presumes I have a builder to work with, and in order to "bootstrap" such a builder I would need to give it a TypeDescription at the very least. But I don't have a TypeDescription; I have a TypeDefinition which might be parameterized, and I don't want to use asErasure().)
(I'm sort of looking for a way to do TypeDescription.Generic.Builder.parameterizedType(myTypeDefinition).asWildcardUpperBound().build(), but I can't obviously do that.)
There does seem to be TypeDescription.Generic.OfWildcardType.Latent::boundedAbove but I can't tell if that's supposed to be an "internal use only" class/method or not.
Such an API was indeed missing. I added an API in today's release (1.11.5) to translate an existing generic type description to a builder what allows transformations to arrays or wildcards. The API is TypeDescription.Generic.Builder.of which accepts a loaded or unloaded generic type description.
I'm new to PLC programming and we need to create a library for a project. We need dynamically created function block instances during the runtime. There is a concept described on the codesys homepage:
https://help.codesys.com/webapp/fb_factory;product=LibDevSummary;version=3.5.15.0
We tried to implement the example but without success. Unfortunately, there is no further information about the concept on the codesys homepage.
Has anybody some advice how to dynamically create fb instances during the runtime on a plc?
When you want to create an instance of an FB dynamically you need first to put the following attribute above the FB-Declaration:
{attribute 'enable_dynamic_creation'}
Then you must make sure you are not calling __NEW(FB_NAME) cyclically.
Then you assign the result of __NEW(FB_NAME) to a pointer:
//Put this is the declaration section
pfbName : POINTER TO FB_NAME;
//Your call to create a dynamic instance
pfbName := __NEW(FB_NAME);
If your pointer = 0 after __NEW returns, it means __NEW failed to allocate memory.
I made a simple classic OOP Person, Teacher, Student example here.
Basically, changing the value of numberOfTeachers inside PLC_PRG will cause the reinitializarion of the array people with the first numberOfTeachers entries being Teachers, and the rest being Students. You can look at the Device Logs where I write messages for creation/destruction of Teacher/Studemt.
PS. I am myself still exploring the possibilities of the Factory Design in CODESYS, so excuse me if I made any mistakes!
will some body explain me in detail that what is SYNTHESIZE_SINGLETON_FOR_CLASS and why we should use it. actually i have search on net that it allow us to access a data without creating object but we can do that by using static method.
so plz if someone can provide me a ref where i can get complete detatil of SYNTHESIZE_SINGLETON_FOR_CLASS from zero.
Do you mean http://cocoawithlove.com/2008/11/singletons-appdelegates-and-top-level.html?
SYNTHESIZE_SINGLETON_FOR_CLASS is just a C macro defined that produce the same code template described in Apple's Creating a Singleton Instance section of the Cocoa Fundamentals Guide. This link already provides the detail what each method does.
I was convinced that there is no way to find COM dependencies of an ActiveX but to my surprise OLEVIEW shows some comments Like:
// TLib : // TLib : OLE Automation : {00020430-0000-0000-C000-000000000046}
importlib("stdole2.tlb");
// TLib : Visual Basic runtime objects and procedures : {EA544A21-C82D-11D1-A3E4-00A0C90AEA82}
importlib("3");
I tried to extract the same information using TypeLibInfoFromFile but based on what I find in MSDN, there is no Api that provides this information. Are you aware of a method to extract this information from OCX or it's Tlb file? Knowing that all my ocxes are compiled with vb6 can I trust this informaion for Imported(Explicitly not in code) interfaces?
Well, I've found the answer to this question. I'll write it here just in case someone would search for the same question. It's possible to find some of dependencies but you can never be sure if you have found them all. Basically you must enumerate every type and interface, and every member of each type to find all types in the module and for every type you find you should check to see if it's in an external TypeLib. in the end you have a List of Typelibs referenced.
The problem with this method lays in the fact you find only the types that are used in the public interface (fields, return values and parameters) and you miss every local object or dynamically created ones. That said you can check this link for an implementation or better yet this one.
To implement "method-missing"-semantics and such in C# 4.0, you have to implement IDynamicObject:
public interface IDynamicObject
{
MetaObject GetMetaObject(Expression parameter);
}
As far as I can figure out IDynamicObject is actually part of the DLR, so it is not new. But I have not been able to find much documentation on it.
There are some very simple example implementations out there (f.x. here and here), but could anyone point me to more complete implementations or some real documentation?
Especially, how exactly are you supposed to handle the "parameter"-parameter?
The short answer is that the MetaObject is what's responsible for actually generating the code that will be run at the call site. The mechanism that it uses for this is LINQ expression trees, which have been enhanced in the DLR. So instead of starting with an object, it starts with an expression that represents the object, and ultimately it's going to need to return an expression tree that describes the action to be taken.
When playing with this, please remember that the version of System.Core in the CTP was taken from a snapshot at the end of August. It doesn't correspond very cleanly to any particular beta of IronPython. A number of changes have been made to the DLR since then.
Also, for compatibility with the CLR v2 System.Core, releases of IronPython starting with either beta 4 or beta 5 now rename everything in that's in the System namespace to be in the Microsoft namespace instead.
If you want an end to end sample including source code, resulting in a dynamic object that stores value for arbitrary properties in a Dictionary then my post "A first look at Duck Typing in C# 4.0" could be right for you. I wrote that post to show how dynamic object can be cast to statically typed interfaces. It has a complete working implementation of a Duck that is a IDynamicObject and may acts like a IQuack.
If you need more information contact me on my blog and I will help you along, as good as I can.
I just blogged about how to do this here:
http://mikehadlow.blogspot.com/2008/10/dynamic-dispatch-in-c-40.html
Here is what I have figured out so far:
The Dynamic Language Runtime is currently maintained as part of the IronPython project. So that is the best place to go for information.
The easiest way to implement a class supporting IDynamicObject seems to be to derive from Microsoft.Scripting.Actions.Dynamic and override the relevant methods, for instance the Call-method to implement function call semantics. It looks like Microsoft.Scripting.Actions.Dynamic hasn't been included in the CTP, but the one from IronPython 2.0 looks like it will work.
I am still unclear on the exact meaning of the "parameter"-parameter, but it seems to provide context for the binding of the dynamic-object.
This presentation also provides a lot of information about the DLR:
Deep Dive: Dynamic Languages in Microsoft .NET by Jim Hugunin.