Literals¶

Literals are the basic building blocks of expressions. They describe a fixed, constant value.

Int Literals¶

Int literals denote integers. They use the expected syntax. For example, the integer three is written as 3.

Float Literals¶

Float literals denote floating point numbers. There are two ways to specify them:

Decimal form: One half can be written as 0.5. Note that neither the integer part nor the decimal part can be omitted, so .5 and 0. are syntax errors.
Scientific notation: Writing very large or very small numbers in decimal notation can be cumbersome. In those cases, scientific notation is helpful. For example, one thousandth can be written in Safe-DS as 1.0e-3 or 1.0E-3. You can read this as 1.0 × 10⁻³. When scientific notation is used, it is allowed to omit the decimal part, so this can be shortened to 1e-3 or 1E-3.

String Literals¶

String literals describe text. Their syntax is simply text enclosed by double quotes: "Hello, world!". Various special characters can be denoted with escape sequences:

Escape sequence	Meaning
`\b`	Backspace
`\f`	Form feed
`\n`	New line
`\r`	Carriage return
`\t`	Tab
`\v`	Vertical tab
`\0`	Null character
`\'`	Single quote
`\"`	Double quote
`\{`	Opening curly brace (used for template strings)
`\\`	Backslash
`\uXXXX`	Unicode character, where `XXXX` is its hexadecimal code

String literals can contain also contain raw line breaks:

"Hello,

world!"

In order to interpolate text with other computed values, use template strings.

Boolean Literals¶

To work with truthiness, Safe-DS has the two boolean literals false and true.

`null` Literal¶

To denote that a value is unknown or absent, use the literal null.