CodeXM types

Like many programming languages, CodeXM is strongly typed. The types that the CodeXM language supports, such as integers (int) or strings (string), are likely to be familiar to you.

In many cases, however, when you declare a variable you don't need to use the name of the type: The type is inferred from the declaration syntax. For example, the following code snippet shows implicit typing:

    let i = 5;

... In this example, i is clearly an integer whose value is 5, so it has the type int.

You can specify a type explicitly. To do so, use a colon ( : ), as shown in the following code snippet:

    let s  : string = "foo"  in
        // Some logic that expects a string named s

Types are described fully in the Syntax reference. These are some of the widely used ones:

bool

A Boolean whose value is either true or false.

int

An integer value; can be positive or zero. (CodeXM treats a minus sign ( - ) as applying a negation operation to a positive integer.)

string

A sequence of characters. A string literal is enclosed in double quotes; for example, "orange".

list<type>

An ordered collection of values; for example, let myList = list [ 1, 2, 4 ];. The values in a list must all be of the same type.

You can access a particular list element by using an array subscript operator; for example, myList[0] designates the first element in myList. Lists are indexed starting from zero.

A list also has a .length property that holds the number of elements in that list. For example, myList.length equals 3.

set<type>

Similar to a list, but the elements are not ordered. (Because of this, they can't be indexed.)

Unlike the mathematical notion of a set, a CodeXM set can have duplicate entries.

enum<literal>

An unordered collection of literal identifiers; for example, let myDecision = { `yes`, `no`, `maybe` }.

The literals in an enum are similar to strings: They can contain any characters, including white space, and are enclosed in back-ticks.