I am studying v8 source code and can't seem to find where all the basic constructors like Array, Object or String are defined.
There is
InstallFunctions($Object.prototype, DONT_ENUM, $Array(
in v8natives.js and
var $Object = global.Object;
in runtime.js, but where global.Object is coming from?
They are coming from the bootstrapper. For example Object and Array.
Related
I would like to do something like :
var data_copy = original_data;
And then do some stuff on data_copy without modifying original_data.
Data_copy and original_data are objects.
Is there a direct way to do that in vala ?
It depends on the object. For structs, this happens automatically. For objects, there isn't a common way. Some objects have a dup() method that can do this, but it is not universal. There's no guaranteed safe way to duplicate an object since it might reference system resources or other things which cannot be duplicated.
I am brand new to Magento and the documentation, primarily the phpDocs, are difficult to navigate. For example,
$attributeSet = Mage::getModel('eav/entity_attribute_set')->load($id);
In the php doc for Class Mage_Eav_Model_Entity_Attribute_Set there is no mention of the method getAttributeSetName() either in inherited methods or otherwise and yet this works.
$attributeSet = Mage::getModel('eav/entity_attribute_set')->load($id);
echo $attributeSet->getAttributeSetName();
So I suppose I have several questions.
Can someone explain to me why the documentation is this way?
Where I can find the mysterious getAttributeSetName() method in the phpDocs?
My theory is that there is some inheritance or a design pattern implementation going on that I'm not understanding, maybe someone can shed some light on this for me.
If you really want to fry your brain, take a look at the source code for Mage_Eav_Model_Entity_Attribute_Set and follow the inheritance chain all the way back. You won't find a getAttributeSetName method defined anywhere.
All Magento objects that inherit from Varien_Object can have arbitrary data members set on them. Try this.
$attributeSet = Mage::getModel('eav/entity_attribute_set')->load($id);
$attributeSet->setFooBazBar('Value');
var_dump($attributeSet->getFooBazBar());
var_dump($attributeSet->getData('foo_baz_bar'));
var_dump($attributeSet->setData('foo_baz_bar','New Value'));
var_dump($attributeSet->getFooBazBar());
You can also get all the data members by using
var_dump($attributeSet->getData());
but be careful dumping these, because if there's a data object that has a circular reference and you're not using something like xDebug, then PHP will have a fit trying to display the object.
Magento stores data properties in a special _data array property. You can get/set values in this array with getData and setData. Magento also has implemented magic getting and setter methods, so when you say something like
$object->getFooBazBar();
The method getFooBazBar is transformed into the data property foo_baz_bar. and then getData is called using this property. It's a little tricky to get your head around, but once you get it you'll start to see how much time you can save using this pattern.
One side effect of this is, of course, it's impossible to infer what data properties any object might have by looking at it's class file, so there's no phpDocs for these methods.
I'm trying to use Boost serialization in my MFC based project so far I had no luck whatsoever but getting error likes that serialize is not a member of CArray or serialize is not a member of CMap .
I cannot figure out how to serialize MFC collection .
Can any one come with a code that successfully serialize and deserialize MFC collection(CString ,CMap) using Boost API .
Thanks in advance
Since you don't have control over the CArray and CMap classes/templates, You will want to work from the non-intrusive instructions. In short, overload a serialize() free function that takes your class and stores the inner elements within it. Depending on the contents of the array or map, you may need to write a further serialize<>() function for them.
I have a memory leak in the Lua part of my application. For whatever reason, my object is not getting deleted when it should (even when I call collectgarbage("collect")). I assume this means I have a dangling reference somewhere.
So how may I obtain a list of where various references to an object reside? For example:
obj = MyObject()
ref = obj
tbl = {obj}
obj = nil
print(getreferences(obj)) -- should print something like _G.ref, _G.tbl[1]
I would simply write my own function for this, but it would not be able to find references contained inside of closures. Any advice?
There's a tool to traverse the whole Lua universe. See http://lua-users.org/lists/lua-l/2006-07/msg00110.html
I am really really really new to all of this, and most of it is unexplored territory. Today I needed to create an anonymous class and put it to a list. I was trying to find how I can make a list of anonymous types, and found that I should make an extension method. I also already figured out an extension method should be in a static class. But what I haven't figured out yet is if there is some pattern that I should use? For now, I have made a static class in my App_Code folder named ExtensionMethods, but have no idea if I should put extension methods of all kinds of types in this class, or if I should make separate classes etc.
To my knowledge you can not implement extension methods for anonymous classes. And this makes sense as really and truly if the class has some semantics it should be made a named class.
To create a list of anonymous classes use this method:
public static List<T> CreateListFromType<T>(T anonType){
return new List<T>();
}
To use this method to create a list, do something like:
var list = CreateListFromType(new {A = default(int), B = default(int)});
Extension method is nothing more than easier-to-read static helper/utility methods. The way you organize them is the same principal as how you organize your normal classes. If you think those should stays together, then try to give them a meaningful, general enough name as the class name. Once you found your class name cannot include what that method doing, then you know that method should belongs to other places.
Firstly extension methods are normal static methods declared like this -
void MyExtension(this MyTarget target, int myparam){ ..
After this the C# compiler adds some syntactic sugar letting you call this method as
target.MyExtension(myparam);
The compiler will replace all these calls with
MyStaticClass.MyExtension(target, myparam);
The important thing is that an extension method is a normal static method. You should follow following guidelines while creating them -
Try to group extension methods for each target class in a separate static class and name it appropriately as Extensions.
Create a new namespace in your application for Extension methods such as MyAppExtensions and keep your static classes inside this namespace. This will keep the coder from misunderstanding them as Extension method and accidentally using them as instance methods.
Make these naming conventions for namespaces and static classes of Extension methods as a standard in the team.
In your extension method check if the first parameter is null and take appropriate action. If you do not then it will be possible to call the method with target being null and may result in unexpected behavior. If the first parameter is allowed to be null then document it clearly.
Consciously decide if it is correct to create and extension method or instance method will be better.
Be careful that the extension method names do not clash with instance method names or other existing extension method names for this class. Following point 1, 2 and 3 will help you achieve this.
I learnt these from Jon Skeet's C# In Depth. You should read it too.
This is how you create a list of an anonymous class.
var anonList = new[]{
new {Foo = "foo", Bar = 2},
new { Foo = "bar", Bar = 3},
}.ToList();
It has nothing to do with writing extension methods.
Edit:
In fact you will have a hard time to use extension methods to create anonymous types since anonymous types can not be used as method parameters or return type.
Edit2:
If you want to convert a list of anonymous types to a list of specific types you can use Select:
class MyClass
{
public string Prop1 {get;set;}
public int Prop2 {get;set;}
}
List<MyClass> myList = anonList.Select(x => new MyClass(){Prop1 = Foo, Prop2 = Bar}).ToList();
I use to put anonymous to DataTable. Due to it's limitation, DataTable provide more functionality such as serialization.