Lexical

Literals at a glance

Every literal form of the language and the type each one has.

since 0.1.0-alpha.1linuxwindowswasm

Description

A literal writes a value directly in the source. Each form has a default type:

The detailed rules are in lang.numeric-literals, lang.string-literals, lang.char-literals and lang.array-and-range-literals. A literal can take a different type from its default when the context asks for one: an integer or float literal becomes a sized numeric type when it is stored in one (see lang.sized-integers and lang.sized-floats), and a one-character single-quoted literal becomes a char.

One of each

console.writeln(42);
console.writeln(3.14);
console.writeln("hello");
console.writeln('hi');
console.writeln(true);
console.writeln([1, 2, 3]);
Range r = 1..10;
console.writeln(r.end);

42
3.140000
hello
hi
true
[1, 2, 3]
10

Rules

• true and false are the only bool values. They are keywords.
• An integer literal has type int unless the context gives it another numeric type.
• A literal containing a decimal point, such as 3.14, has type float. There is no exponent notation: 1e3 is a syntax error, so write 1000.0.
• A string literal has type string whichever quote style is used. Only a single-quoted literal can become a char.
• An array literal has type Array<T>, and a range literal a..b has type Range.

Examples

A float literal is never an int, and mixing them gives a float:

Default literal types

console.writeln(7 / 2);
console.writeln(7 / 2.0);
console.writeln(true == !false);

3
3.500000
true

Notes

Printing a float always shows six decimal places.