Tutorial by Examples: u

A prvalue (pure-rvalue) expression is an expression which lacks identity, whose evaluation is typically used to initialize an object, and which can be implicitly moved from. These include, but are not limited to: Expressions that represent temporary objects, such as std::string("123"). ...

An xvalue (eXpiring value) expression is an expression which has identity and represents an object which can be implicitly moved from. The general idea with xvalue expressions is that the object they represent is going to be destroyed soon (hence the "eXpiring" part), and therefore implici...

An lvalue expression is an expression which has identity, but cannot be implicitly moved from. Among these are expressions that consist of a variable name, function name, expressions that are built-in dereference operator uses and expressions that refer to lvalue references. The typical lvalue is s...

A glvalue (a "generalized lvalue") expression is any expression which has identity, regardless of whether it can be moved from or not. This category includes lvalues (expressions that have identity but can't be moved from) and xvalues (expressions that have identity, and can be moved from)...

An rvalue expression is any expression which can be implicitly moved from, regardless of whether it has identity. More precisely, rvalue expressions may be used as the argument to a function that takes a parameter of type T && (where T is the type of expr). Only rvalue expressions may be gi...

Background TypeScript is a typed superset of JavaScript that compiles directly to JavaScript code. TypeScript files commonly use the .ts extension. Many IDEs support TypeScript without any other setup required, but TypeScript can also be compiled with the TypeScript Node.JS package from the command...

You can see what "hunks" of work would be staged for commit using the patch flag: git add -p or git add --patch This opens an interactive prompt that allows you to look at the diffs and let you decide whether you want to include them or not. Stage this hunk [y,n,q,a,d,/,s,e,?]? ...

In this example, we illustrate string manipulation in MATLAB MEX. We will create a MEX-function that accepts a string as input from MATLAB, copy the data into C-string, modify it and convert it back to mxArray returned to the MATLAB side. The main objective of this example is to show how strings ca...

Since anonymous types are not named, variables of those types must be implicitly typed (var). var anon = new { Foo = 1, Bar = 2 }; // anon.Foo == 1 // anon.Bar == 2 If the member names are not specified, they are set to the name of the property/variable used to initialize the object. int foo ...

Anonymous types allow the creation of objects without having to explicitly define their types ahead of time, while maintaining static type checking. var anon = new { Value = 1 }; Console.WriteLine(anon.Id); // compile time error Conversely, dynamic has dynamic type checking, opting for runtime ...

Generic methods allow the use of anonymous types through type inference. void Log<T>(T obj) { // ... } Log(new { Value = 10 }); This means LINQ expressions can be used with anonymous types: var products = new[] { new { Amount = 10, Id = 0 }, new { Amount = 20, Id = 1 }, ...

Using generic constructors would require the anonymous types to be named, which is not possible. Alternatively, generic methods may be used to allow type inference to occur. var anon = new { Foo = 1, Bar = 2 }; var anon2 = new { Foo = 5, Bar = 10 }; List<T> CreateList<T>(params T[] it...

Anonymous type equality is given by the Equals instance method. Two objects are equal if they have the same type and equal values (through a.Prop.Equals(b.Prop)) for every property. var anon = new { Foo = 1, Bar = 2 }; var anon2 = new { Foo = 1, Bar = 2 }; var anon3 = new { Foo = 5, Bar = 10 }; ...

round Rounds the value to the nearest whole number with x.5 rounding up (but note that -x.5 rounds down). round(3.000) // 3 round(3.001) // 3 round(3.499) // 3 round(3.500) // 4 round(3.999) // 4 round(-3.000) // -3 round(-3.001) // -3 round(-3.499) // -3 round(-3.500) // -4 *** careful...

arc4random_uniform(someNumber: UInt32) -> UInt32 This gives you random integers in the range 0 to someNumber - 1. The maximum value for UInt32 is 4,294,967,295 (that is, 2^32 - 1). Examples: Coin flip let flip = arc4random_uniform(2) // 0 or 1 Dice roll let roll = arc4random_...

If you have cloned a fork (e.g. an open source project on Github) you may not have push access to the upstream repository, so you need both your fork but be able to fetch the upstream repository. First check the remote names: $ git remote -v origin https://github.com/myusername/repo.git (fetch...

Installing Visual Studio If you do not have Visual Studio installed, you can download the free Visual Studio Community Edition here. If you already have it installed, you can proceed to the next step. Creating an ASP.NET Core MVC Application. Open Visual Studio. Select File > New Project. ...

By default, all the methods declared in a protocol are required. This means that any class that conforms to this protocol must implement those methods. It is also possible to declare optional methods. These method can be implemented only if needed. You mark optional methods with the @optional dire...

If you screw up a rebase, one option to start again is to go back to the commit (pre rebase). You can do this using reflog (which has the history of everything you've done for the last 90 days - this can be configured): $ git reflog 4a5cbb3 HEAD@{0}: rebase finished: returning to refs/heads/foo 4...

toList flattens a Foldable structure t a into a list of as. ghci> toList [7, 2, 9] -- t ~ [] [7, 2, 9] ghci> toList (Right 'a') -- t ~ Either e "a" ghci> toList (Left "foo") -- t ~ Either String [] ghci> toList (3, True) -- t ~ (,) Int [True] toList is ...