Range

The syntax for defining a range is a..b, where a and b are non-negative integers, for example 2..10.

You can omit either a or b, in which case the range becomes open.

Depending on the number of delimiters provided, a range can be classified as:

• Closed range: a..b
• Open on the left end: ..b
• Open on the right end: a..
• Open on both ends: ..

The behavior of open ranges is not universally defined. Each function that accepts a range defines its own behavior. See .read as an example, whose strategy is common for slicing operations across the standard library.

The .. operator is syntactic sugar for the .range {from} {to} function, with the difference that the operator accepts only literal values. When the ends of the range need to be evaluated dynamically, such as through a mathematical operation, .range is the appropriate choice.

.code
    .read {assets/point.ts}

export class Point {
    x: number;
    y: number;

    constructor(x: number, y: number) {
        this.x = x;
        this.y = y;
    }
}

.code
    .read {assets/point.ts} lines:{5..7}

    constructor(x: number, y: number) {
        this.x = x;
        this.y = y;

.code 
    .read {assets/point.ts} lines:{..3}

export class Point {
    x: number;
    y: number;

.code
    .read {assets/point.ts} lines:{5..}

    constructor(x: number, y: number) {
        this.x = x;
        this.y = y;
    }
}