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Why can templates only be implemented in the header file?
...f;
When reading this line, the compiler will create a new class (let's call it FooInt), which is equivalent to the following:
struct FooInt
{
int bar;
void doSomething(int param) {/* do stuff using int */}
}
Consequently, the compiler needs to have access to the implementation of the m...
Get name of current class?
...return super(MyType, cls).__new__(cls, name, bases, newattrs)
class MyBaseFoo(object):
__metaclass__ = InputAssigningMetaclass
class foo(MyBaseFoo):
# etc, no need to create 'input'
class foo2(MyBaseFoo):
# etc, no need to create 'input'
...
What is setup.py?
...
It helps to install a python package foo on your machine (can also be in virtualenv) so that you can import the package foo from other projects and also from [I]Python prompts.
It does the similar job of pip, easy_install etc.,
Using setup.py
Let's star...
Readonly Properties in Objective-C?
...ing"; // Notice the underscore prefix of var name.
That’s it, that’s all you need. No muss, no fuss.
Details
As of Xcode 4.4 and LLVM Compiler 4.0 (New Features in Xcode 4.4), you need not mess with the chores discussed in the other answers:
The synthesize keyword
Declaring a variable
Re-...
Why is Python running my module when I import it, and how do I stop it?
...program I'm building that can be run in either of 2 ways: the first is to call "python main.py" which prompts the user for input in a friendly manner and then runs the user input through the program. The other way is to call "python batch.py -file- " which will pass over all the friendly input gat...
How does collections.defaultdict work?
...
Usually, a Python dictionary throws a KeyError if you try to get an item with a key that is not currently in the dictionary. The defaultdict in contrast will simply create any items that you try to access (provided of course th...
define() vs. const
...nts: Either using the const keyword or using the define() function:
const FOO = 'BAR';
define('FOO', 'BAR');
The fundamental difference between those two ways is that const defines constants at compile time, whereas define defines them at run time. This causes most of const's disadvantages. Some ...
Python decorators in classes
...ething like this do what you need?
class Test(object):
def _decorator(foo):
def magic( self ) :
print "start magic"
foo( self )
print "end magic"
return magic
@_decorator
def bar( self ) :
print "normal call"
test = Test()
t...
Using “super” in C++
... the first time C++ was standardized.
Dag Bruck proposed this extension, calling the base class "inherited." The proposal mentioned the multiple inheritance issue, and would have flagged ambiguous uses. Even Stroustrup was convinced.
After discussion, Dag Bruck (yes, the same person making the p...
Python memoising/deferred lookup property decorator
...nce, but they're a real bottleneck to calculate that first time and only really accessed for special cases. Hence they can also be cached after they've been retrieved from the database (this therefore fits the definition of memoisation where the input is simply "no input").
...