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How to set the prototype of a JavaScript object that has already been instantiated?
Suppose I have an object foo in my JavaScript code. foo is a complex object and it is generated somewhere else. How can I change the prototype of the foo object?
...
Can I export a variable to the environment from a bash script without sourcing it?
...he script in the context of the calling shell:
$ cat set-vars1.sh
export FOO=BAR
$ . set-vars1.sh
$ echo $FOO
BAR
Another way is to have the script, rather than setting an environment variable, print commands that will set the environment variable:
$ cat set-vars2.sh
#!/bin/bash
echo export FO...
How to reference a method in javadoc?
...Method in the same class:
/** See also {@link #myMethod(String)}. */
void foo() { ... }
Method in a different class, either in the same package or imported:
/** See also {@link MyOtherClass#myMethod(String)}. */
void foo() { ... }
Method in a different package and not imported:
/** See also {@l...
What is the curiously recurring template pattern (CRTP)?
...e polymorphism. Here's a very simple example. In the below example, ProcessFoo() is working with Base class interface and Base::Foo invokes the derived object's foo() method, which is what you aim to do with virtual methods.
http://coliru.stacked-crooked.com/a/2d27f1e09d567d0e
template <typenam...
Cannot pass null argument when using type hinting
...ou can explicitly declare a variable to be null with this syntax
function foo(?Type $t) {
}
this will result in
$this->foo(new Type()); // ok
$this->foo(null); // ok
$this->foo(); // error
So, if you want an optional argument you can follow the convention Type $t = null whereas if you...
Can someone explain __all__ in Python?
...> import * is used on the module.
For example, the following code in a foo.py explicitly exports the symbols bar and baz:
__all__ = ['bar', 'baz']
waz = 5
bar = 10
def baz(): return 'baz'
These symbols can then be imported like so:
from foo import *
print(bar)
print(baz)
# The following w...
Local dependency in package.json
... npm. Example:
{
"name": "baz",
"dependencies": {
"bar": "file:../foo/bar"
}
}
Any of the following paths are also valid:
../foo/bar
~/foo/bar
./foo/bar
/foo/bar
The local package will be copied to the prefix (./node-modules).
npm < 2.0.0
Put somelocallib as dependency in your p...
Rails where condition using NOT NIL
...
The canonical way to do this with Rails 3:
Foo.includes(:bar).where("bars.id IS NOT NULL")
ActiveRecord 4.0 and above adds where.not so you can do this:
Foo.includes(:bar).where.not('bars.id' => nil)
Foo.includes(:bar).where.not(bars: { id: nil })
When working...
Get top n records for each group of grouped results
...s can be returned, as shown below:
.headers on
.mode column
CREATE TABLE foo (person, groupname, age);
INSERT INTO foo VALUES('Paul',2,36);
INSERT INTO foo VALUES('Laura',2,39);
INSERT INTO foo VALUES('Joe',2,36);
INSERT INTO foo VALUES('Bob',1,32);
INSERT INTO foo VALUES('Jill',1,34);
INSERT INTO...
ReadOnlyCollection or IEnumerable for exposing member collections?
...pe to be an immutable collection, and then expose that directly - assuming Foo itself is immutable, of course.
Updated answer to address the question more directly
Is there any reason to expose an internal collection as a ReadOnlyCollection rather than an IEnumerable if the calling code only it...