Numeric Literals

Numbers can be written in various bases. Numbers are assumed to be decimal by default. Non-decimal literals have a specific prefix.

Numeral system	Prefix	Characters
Decimal	None	one or more numbers (0 to 9)
Binary	0b	one or more zeros or ones (0 or 1)
Octal	0o	one or more numbers in the range 0 to 7
Hexadecimal	0x	one or more numbers, or characters a to f, lowercase or uppercase

// A decimal number
//
1234567890  // is `1234567890`

// A binary number
//
0b101010  // is `42`

// An octal number
//
0o12345670  // is `2739128`

// A hexadecimal number
//
0x1234567890ABCabc  // is `1311768467294898876`

// Invalid: unsupported prefix 0z
//
0z0

// A decimal number with leading zeros. Not an octal number!
00123 // is `123`

// A binary number with several trailing zeros.
0b001000  // is `8`

Decimal numbers may contain underscores (_) to logically separate components.

let largeNumber = 1_000_000

// Invalid: Value is not a number literal, but a variable.
let notNumber = _123

Underscores are allowed for all numeral systems.

let binaryNumber = 0b10_11_01