To see all the facts involving the le relation from the prelude:
Coq < Search le.
le_n: forall n : nat, n <= n
le_S: forall n m : nat, n <= m -> n <= S m
...
max_l: forall n m : nat, m <= n -> Nat.max n m = n
max_r: forall n m : nat, n <= m -> Nat.max n m = m
...
...
Session Types are a way to tell the compiler about the protocol you want to use to communicate between threads - not protocol as in HTTP or FTP, but the pattern of information flow between threads. This is useful since the compiler will now stop you from accidentally breaking your protocol and causi...
Let's say your launch activity is called MainActivity, in your app com.example.myapp.
In the manifest:
<activity
android:name=".MainActivity"
>
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
...
Bridge pattern decouples abstraction from implementation so that both can vary independently. It has been achieved with composition rather than inheritance.
Bridge UML diagram from wikipedia:
You have four components in this pattern.
Abstraction: It defines an interface
RefinedAbstraction: It ...
SELECT SYSDATE();
This function returns the current date and time as a value in 'YYYY-MM-DD HH:MM:SS' or YYYYMMDDHHMMSS format, depending on whether the function is used in a string or numeric context. It returns the date and time in the current time zone.
SELECT NOW();
This function is a...
The dimension attribute on an object specifies that that object is an array. There are, in Fortran 2008, five array natures:1
explicit shape
assumed shape
assumed size
deferred shape
implied shape
Take the three rank-1 arrays2
integer a, b, c
dimension(5) a ! Explicit shape (default ...
If the value of the href-attribute begins with tel:, your device will dial the number when you click it. This works on mobile devices or on computers/tablets running software – like Skype or FaceTime – that can make phone calls.
<a href="tel:11234567890">Call us</a>
Most de...
(This is a request for a good example that shows how to construct a SELECT using CONCAT, then prepare+execute it. Please emphasize the use of @variables versus DECLAREd variables -- it makes a big difference, and it is something that novices (include myself) stumble over.)
To declare a bean, simply annotate a method with the @Bean annotation or annotate a class with the @Component annotation (annotations @Service, @Repository, @Controller could be used as well).
When JavaConfig encounters such a method, it will execute that method and register the return value as a b...
Enabled directory index means that if someone access to any folder which don't contains index.php , index.html, index.htm or any other default file defined in DirectoryIndex in apache configuration then all files in that folder will be listed in browser if you try to visit that page.
Often director...
java.lang.ref package provides reference-object classes, which support a limited degree of interaction with the garbage collector.
Java has four main different reference types. They are:
Strong Reference
Weak Reference
Soft Reference
Phantom Reference
1. Strong Reference
This is the usual...
Problem
There is a series of repeating elements in page that you need to know which one an event occurred on to do something with that specific instance.
Solution
Give all common elements a common class
Apply event listener to a class. this inside event handler is the matching selector elemen...
When expecting someone to reproduce an R code that has random elements in it, the set.seed() function becomes very handy.
For example, these two lines will always produce different output (because that is the whole point of random number generators):
> sample(1:10,5)
[1] 6 9 2 7 10
>...
Be aware that Microsoft Excel 2013 (and higher) uses Single Document
Interface (SDI) and that Excel 2010 (And below) uses Multiple Document
Interfaces (MDI).
This implies that for Excel 2013 (SDI), each workbook in a single instance of Excel contains its own ribbon UI:
Conversely for Excel...
From the documentation :
In C#, arguments can be passed to parameters either by value or by
reference. Passing by reference enables function members, methods,
properties, indexers, operators, and constructors to change the value
of the parameters and have that change persist in the calling
e...
The DATE data type does not handle time zones or changes in daylight savings time.
Either:
use the TIMESTAMP WITH TIME ZONE data type; or
handle the changes in your application logic.
A DATE can be stored as Coordinated Universal Time (UTC) and converted to the current session time zone like...
There is overflow in the following code
int x = int.MaxValue;
Console.WriteLine(x + x + 1L); //prints -1
Whereas in the following code there is no overflow
int x = int.MaxValue;
Console.WriteLine(x + 1L + x); //prints 4294967295
This is due to the left-to-right ordering of the operations...
