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Why doesn't 'ref' and 'out' support polymorphism?
...nswer as the basis for this blog entry:
Why do ref and out parameters not allow type variation?
See the blog page for more commentary on this issue. Thanks for the great question.
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Let's suppose you have classes Animal, Mammal, Reptile, Giraffe, Turtle and Tiger, with the obvious s...
Why does the Scala compiler disallow overloaded methods with default arguments?
... such method overloadings could become ambiguous, why does the compiler disallow code which is neither ambiguous at compile time nor at run time?
...
What is the equivalent of the C# 'var' keyword in Java?
...to give a proper type to myData. 6 years ago, this was impossible in Java (all Types had names, even if they were extremely verbose and unweildy). I do not know if this has changed in the mean time.
var is not the same as dynamic. variables are still 100% statically typed. This will not compile:
va...
Is pass-by-value a reasonable default in C++11?
...by value into functions and methods is slow for large objects, and is generally frowned upon. Instead, C++ programmers tend to pass references around, which is faster, but which introduces all sorts of complicated questions around ownership and especially around memory management (in the event that ...
How do I get the object if it exists, or None if it does not exist?
... python is to wrap it in a try catch:
try:
go = SomeModel.objects.get(foo='bar')
except SomeModel.DoesNotExist:
go = None
What I did do, is to subclass models.Manager, create a safe_get like the code above and use that manager for my models. That way you can write: SomeModel.objects.safe_...
SQLAlchemy: What's the difference between flush() and commit()?
...
A Session object is basically an ongoing transaction of changes to a database (update, insert, delete). These operations aren't persisted to the database until they are committed (if your program aborts for some reason in mid-session transaction, any...
Why no ICloneable?
...bad API now, since it does not specify whether the result is a deep or a shallow copy. I think this is why they do not improve this interface.
You can probably do a typed cloning extension method, but I think it would require a different name since extension methods have less priority than original...
Is it better to return null or empty collection?
...llection might mean "0 items", returning Null could mean "no collection at all" - eg. if you are parsing HTML, looking for an <ul> with id="foo", <ul id="foo"></ul> could return empty collection; if there is no <ul> with id="foo" a null return would be better (unless you want...
What exactly are iterator, iterable, and iteration?
...loop, or map, or a list comprehension, etc. in Python, the next method is called automatically to get each item from the iterator, thus going through the process of iteration.
A good place to start learning would be the iterators section of the tutorial and the iterator types section of the standar...
How do I configure different environments in Angular.js?
...strict";
angular.module("config", []).constant("ENV", "development");
Finally, I declare the dependency on whatever modules need it:
// the 'config' dependency is generated via grunt
var app = angular.module('myApp', [ 'config' ]);
Now my constants can be dependency injected where needed. E.g.,...