Tutorial by Examples: lit

Abilities are defined in the Ability class using can and cannot methods. Consider the following commented example for basic reference: class Ability include CanCan::Ability def initialize(user) # for any visitor or user can :read, Article if user if user.admin? ...

Once the number of abilities definitions start to grow in number, it becomes more and more difficult to handle the Ability file. The first strategy to handle these issue is to move abilities into meaningful methods, as per this example: class Ability include CanCan::Ability def initialize(...

Download the Atlassian conversion utility here. This utility requires Java, so please ensure that you have the Java Runtime Environment JRE installed on the machine you plan to do the conversion. Use the command java -jar svn-migration-scripts.jar verify to check if your machine is missing any of t...

To split a JID into its component parts (the localpart, domainpart, and resourcepart), the following algorithm should be used (where the localpart is represented by lp, the resourcepart by rp, and the domainpart by dp and ∈ is used to check if the given character is included in the string): Note ...

The .every method tests if all array elements pass a provided predicate test. To test all objects for equality, you can use the following code snippets. [1, 2, 1].every(function(item, i, list) { return item === list[0]; }); // false [1, 1, 1].every(function(item, i, list) { return item === list[0...

String literal types allow you to specify the exact value a string can have. let myFavoritePet: "dog"; myFavoritePet = "dog"; Any other string will give a error. // Error: Type '"rock"' is not assignable to type '"dog"'. // myFavoritePet = "rock&qu...

Split Function returns a zero-based, one dimensional array containing a specified number of substrings. Syntax Split(expression [, delimiter [, limit [, compare]]]) PartDescriptionexpressionRequired. String expression containing substrings and delimiters. If expression is a zero-length string(&q...

If logic of generic class or method requires checking equality of values having generic type, use EqualityComparer<TType>.Default property: public void Foo<TBar>(TBar arg1, TBar arg2) { var comparer = EqualityComparer<TBar>.Default; if (comparer.Equals(arg1,arg2) {...

In this example will render five <li> tags <ul id="render-sample"> <li v-for="n in 5"> Hello Loop </li> </ul>

Strings are immutable. You just cannot change existing string. Any operation on the string crates a new instance of the string having new value. It means that if you need to replace a single character in a very long string, memory will be allocated for a new value. string veryLongString = ... // m...

Linux has a command for almost any tasks and most of them are intuitive and easily interpreted. Getting Help in Linux CommandUsabilityman <name>Read the manual page of <name>.man <section> <name>Read the manual page of <name>, related to the given section.man -k <e...

Sometimes you may only need to simulate an event with two outcomes, maybe with different probabilities, but you may find yourself in a situation that calls for many possible outcomes with different probabilities. Let's imagine you want to simulate an event that has six equally probable outcomes. T...

You can open a new split within Vim with the following commands, in normal mode: Horizontally: :split <file name> :new Vertically: :vsplit <file name> :vnew split will open the file in a new split at the top or left of your screen (or current split.) :sp and :vs are convenie...

The backface-visibility property relates to 3D transforms. With 3D transforms and the backface-visibility property, you're able to rotate an element such that the original front of an element no longer faces the screen. For example, this would flip an element away from the screen: JSFIDDLE <d...

Unlike Java, Dart doesn’t have the keywords public, protected, and private. If an identifier starts with an underscore _, it’s private to its library. If you for example have class A in a separate library file (eg, other.dart), such as: library other; class A { int _private = 0; testA()...

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Multiple FOR clauses are allowed in a LOOP. The loop finishes when the first of these clauses finishes: (loop for a in '(1 2 3 4 5) for b in '(a b c) collect (list a b)) ;; Evaluates to: ((1 a) (2 b) (3 c)) Other clauses that determine if the loop should continue can be combined: ...

The OverloadedStrings language extension allows the use of normal string literals to stand for Text values. {-# LANGUAGE OverloadedStrings #-} import qualified Data.Text as T myText :: T.Text myText = "overloaded"

{-# LANGUAGE OverloadedStrings #-} import qualified Data.Text as T myText :: T.Text myText = "mississippi" splitOn breaks a Text up into a list of Texts on occurrences of a substring. ghci> T.splitOn "ss" myText ["mi","i","ippi"] sp...

Functionality in metaclasses can be changed so that whenever a class is built, a string is printed to standard output, or an exception is thrown. This metaclass will print the name of the class being built. class VerboseMetaclass(type): def __new__(cls, class_name, class_parents, class_dict)...