Values can be given names using let:
# let a = 1;;
val a : int = 1
You can use similar syntax to define a function. Just provide additional parameters for the arguments.
# let add arg1 arg2 = arg1 + arg2;;
val add : int -> int -> int = <fun>
We can call it like this:
# add 1...
The function keyword automatically has pattern matching when you define the
body of your function. Observe it below:
# let foo = function
0 -> "zero"
| 1 -> "one"
| 2 -> "couple"
| 3 -> "few"
| _ -> "many";;
val foo : int ->...
3.0
let string = "My fantastic string"
var index = string.startIndex
while index != string.endIndex {
print(string[index])
index = index.successor()
}
Note: endIndex is after the end of the string (i.e. string[string.endIndex] is an error, but string[string.startIndex] i...
[1, 2, [[3, 4], [5]], 6].flatten # => [1, 2, 3, 4, 5, 6]
If you have a multi-dimensional array and you need to make it a simple (i.e. one-dimensional) array, you can use the #flatten method.
Standard enumerations allow users to declare a useful name for a set of integers. The names are collectively referred to as enumerators. An enumeration and its associated enumerators are defined as follows:
enum myEnum
{
enumName1,
enumName2,
};
An enumeration is a type, one which is...
A common use for enumerators is for switch statements and so they commonly appear in state machines. In fact a useful feature of switch statements with enumerations is that if no default statement is included for the switch, and not all values of the enum have been utilized, the compiler will issue ...
Enums in Swift are much more powerful than some of their counterparts in other languages, such as C. They share many features with classes and structs, such as defining initialisers, computed properties, instance methods, protocol conformances and extensions.
protocol ChangesDirection {
mutati...
Using functions that take in and execute closures can be extremely useful for sending a block of code to be executed elsewhere. We can start by allowing our function to take in an optional closure that will (in this case) return Void.
func closedFunc(block: (()->Void)? = nil) {
print("...
A protocol may specify that only a class can implement it through using the class keyword in its inheritance list. This keyword must appear before any other inherited protocols in this list.
protocol ClassOnlyProtocol: class, SomeOtherProtocol {
// Protocol requirements
}
If a non-class typ...
With Gson, you can read JSON dataset and map them to a custom class MyClass.
Since Gson is not serializable, each executor needs its own Gson object. Also, MyClass must be serializable in order to pass it between executors.
Note that the file(s) that is offered as a json file is not a typical JSON...
We define the type of boolean expressions whose atoms are identified by strings as
type expr =
| Atom of string
| Not of expr
| And of expr * expr
| Or of expr * expr
and can evaluate these expressions using an oracle : string -> bool giving the values of the atoms we find as follows:
le...
Pattern matching allows to deconstruct complex values and it is by no way limited to the “outer most” level of the representation of a value. To illustrate this, we implement the function transforming a boolean expression into a boolean expression where all negations are only on atoms, the so calle...
There are several additional attributes that the Volley NetworkImageView adds to the standard ImageView. However, these attributes can only be set in code. The following is an example of how to make an extension class that will pick up the attributes from your XML layout file and apply them to the N...
A reference to an option &Option<T> cannot be unwrapped if the type T is not copyable. The solution is to change the option to &Option<&T> using as_ref().
Rust forbids transferring of ownership of objects while the objects are borrowed. When the Option itself is borrowed (&a...
Woocommerce is a plugin for WordPress and can be installed like any other WordPress plugin. WooCommerce can only be installed on self hosted installations of WordPress, it cannot be installed onto a site hosted by the wordpress.com service.
If you don't have WordPress installed for your website, fo...
There are some ways to break or change a loop's flow.
break; will exit the current loop, and will not execute any more lines within that loop.
continue; will not execute any more code within the current iteration of the loop, but will remain in the loop.
The following loop will execute 101 times ...
Functions are of the type Function:
function example():void { }
trace(example is Function); // true
They can be referenced by other variables with the type Function:
var ref:Function = example;
ref(); // ref.call(), ref.apply(), etc.
And they can be passed in as arguments for parameters wh...
The C++ approach - new and delete
In a language like C++, the application program is responsible for managing the memory used by dynamically allocated memory. When an object is created in the C++ heap using the new operator, there needs to be a corresponding use of the delete operator to dispose o...
