Keywords

Orn has some reserved keywords that they cannot be used as identifiers or outside of their proper contexts. These are:

• int
• unsigned
• double
• float
• bool
• void
• char
• string
• if
• else
• elif
• while
• ret
• break
• continue
• struct
• enum
• import
• true
• false
• let
• const
• fn
• sizeof
• syscall
• for
• in
• match
• defer
• impl
• type
• as
• null

Identifiers

IDENTIFIER = [a-zA-Z_] [a-zA-Z0-9_]*

Identifiers that are are valid:

• foo
• _foo
• foo123
• foo_bar
• FOO

Identifiers that start with an underscore are usually used for intentionally unused variables, for example:

fn foo() {
	let _unused = 42;
}

This won’t trigger unused variable warning.

Literals

NUMBER = DECIMAL | HEX_LITERAL | OCT_LITERAL | BIN_LITERAL

DECIMAL = [0-9]+ ("." [0-9]+)?
HEX_LITERAL = "0" ("x" | "X") [0-9a-fA-F]+
OCT_LITERAL = "0" ("o" | "O") [0-7]+
BIN_LITERAL = "0" ("b" | "B") [01]+

STRING_LITERAL = "\"" (escape | [^"\\])* "\""
CHAR_LITERAL = "'" (escape | [^'\\]) "'"

escape = "\\" [nrt0\\'"x] | "\\x" [0-9a-fA-F]{2}

bool_literals = TRUE | FALSE

Number literals:

• 42
• 3.14
• 0x2A
• 0o52
• 0b101010

Hex, octal and binary becomes decimal numbers at compile time at the parser.

String literals:

• "Hello, world!"
• "Line 1\nLine 2"

Character literals:

• 'a'
• '\n'

Bool literals:

• true
• false

Operators and Punctuation

Punctuation

Punctuation tokens are used as operators, separators, and delimiters.

PUNCTUATION = "..."
            | "+="
            | "-="
            | "*="
            | "/="
            | "%="
            | "=="
            | "!="
            | "<="
            | ">="
            | "<<"
            | ">>"
            | "&&"
            | "||"
            | "->"
            | "<-"
            | "=>"
            | "::"
            | ".."
            | "++"
            | "--"
            | "+"
            | "-"
            | "*"
            | "/"
            | "%"
            | "!"
            | "~"
            | "&"
            | "|"
            | "^"
            | "="
            | "<"
            | ">"
            | "."
            | ","
            | ":"
            | ";"
            | "?"
            | "_"
            | "("
            | ")"
            | "{"
            | "}"
            | "["
            | "]"

Multi character tokens are matched longest first.

Delimiters

Bracket punctuation must always appear in matched pairs. The three types are:

An unmatched delimiter is a compile error.