Lexical structure

Comments

// line comment
/* block comment */
/// documentation for the next declaration
/** block documentation */

Documentation comments attach to the declaration that follows; the language server shows them on hover and the knowledge graph records them.

Identifiers and keywords

Identifiers are letters, digits and _, not starting with a digit. Keywords: if else match for in while break continue return type import pub as with spawn sandbox test rt lambda true false behavior. Built-in type names (Int, Str, List, Option, …) are ordinary identifiers.

Names

A name’s case says what it is (E0222):

• values, functions, parameters, fields and behavior verbs start with a lowercase letter or _;
• types, behaviors and sum variants start with an uppercase letter;
• a single uppercase letter (T, K, V, N) is a type parameter and never names a declared type.

So a value never collides with a type, and (T)x is always a cast.

Literals

Literal	Examples	Type
integer	42, 0x2A, 0o52, 0b101010	adopts its context, else Int (§ numbers)
float	3.14, 2.0	Float
decimal	1.5m, 5m	Dec (Dec(34))
character	'a', '\n'	Int (the code point)
string	"text\n"	Str
raw string	r"C:\path"	Str, no escapes
byte string	b"bytes"	Bytes
f-string	f"x = {x}"	Str
boolean	true, false	Bool
list	[1, 2, 3]	List(T)
map	{"a": 1}	Map(K, V)
set	{1, 2}	Set(T)
record	Point {.x = 1, .y = 2}, Point { x = 1, y = 2 }	the record type
location	#location	SourceLoc

String escapes are \n, \t, \r, \\ and \"; write any other character directly (source files are UTF-8). A string cannot contain a NUL character. There is no null literal.