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How to implement the factory method pattern in C++ correctly
...memory>
class FactoryReleaseOwnership{
public:
std::unique_ptr<Foo> createFooInSomeWay(){
return std::unique_ptr<Foo>(new Foo(some, args));
}
};
// Factory retains object ownership
// Thus returning a reference.
#include <boost/ptr_container/ptr_vector.hpp>
clas...
Are (non-void) self-closing tags valid in HTML5?
...
In HTML 4, <foo / (yes, with no > at all) means <foo> (which leads to <br /> meaning <br>> (i.e. <br>&gt;) and <title/hello/ meaning <title>hello</title>). This is an SGML rule that browse...
Script parameters in Bash
...ation_file.txt
Explanation on double quotes;
consider three scripts:
# foo.sh
bash bar.sh $1
# cat foo2.sh
bash bar.sh "$1"
# bar.sh
echo "1-$1" "2-$2"
Now invoke:
$ bash foo.sh "a b"
1-a 2-b
$ bash foo2.sh "a b"
1-a b 2-
When you invoke foo.sh "a b" then it invokes bar.sh a b (two argum...
How to make a chain of function decorators?
...)
func()
print("~salad~")
return wrapper
def sandwich(food="--ham--"):
print(food)
sandwich()
#outputs: --ham--
sandwich = bread(ingredients(sandwich))
sandwich()
#outputs:
#</''''''\>
# #tomatoes#
# --ham--
# ~salad~
#<\______/>
Using the Python decorator syn...
Set a persistent environment variable from cmd.exe
...ist after the cmd window has been closed.
For example, to set an env var "foo" with value of "bar":
setx foo bar
Though it's worth reading the 'notes' that are displayed if you print the usage (setx /?), in particular:
2) On a local system, variables created or modified by this tool will be ...
EF Code First “Invalid column name 'Discriminator'” but no inheritance
....Schema.TableAttribute referring to the same table.
for example:
[Table("foo")]
public class foo
{
// some stuff here
}
[Table("foo")]
public class fooExtended
{
// more stuff here
}
changing the second one from foo to foo_extended fixed this for me and I'm now using Table Per Type (TPT...
What are the differences between vector and list data types in R?
...ven other lists:
x <- list(values=sin(1:3), ids=letters[1:3], sub=list(foo=42,bar=13))
x # print the list
x$values # Get one element
x[["ids"]] # Another way to get an element
x$sub$foo # Get sub elements
x[[c(3,2)]] # Another way (gets 13)
str(x) # A "summary" of the list's content
Li...
Java SafeVarargs annotation, does a standard or best practice exist?
...e a variable number of arguments of a type-parameter type:
<T> void foo(T... args);
In Java, varargs are a syntactic sugar that undergoes a simple "re-writing" at compile-time: a varargs parameter of type X... is converted into a parameter of type X[]; and every time a call is made to this ...
how to break the _.each function in underscore.js
...s out of the loop when the element is found:
var searchArr = [{id:1,text:"foo"},{id:2,text:"bar"}];
var count = 0;
var filteredEl = _.find(searchArr,function(arrEl){
count = count +1;
if(arrEl.id === 1 ){
return arrEl;
}
});
...
What's the difference between an object initializer and a constructor?
...ation logic.
Below you can see an example of a constructor.
public class Foo
{
private SomeClass s;
public Foo(string s)
{
s = new SomeClass(s);
}
}
Now consider the following example:
public class Foo
{
public SomeClass s { get; set; }
public Foo() {}
}
You co...