2.1. Lexical Structure

2.1.1. Identifiers

Identifiers start with an alphabetic character (and not the symbol ‘_’) followed by any number of alphabetic characters, ‘_’ or digits ([0-9]). daScript is a case sensitive language meaning that the lowercase and uppercase representation of the same alphabetic character are considered different characters. For instance, “foo”, “Foo” and “fOo” are treated as 3 distinct identifiers.

2.1.2. Keywords

The following words are reserved and cannot be used as identifiers:

struct	def	recover	panic	let	var
continue	break	finally	new	delete	enum
enum	for	while	if	else	elif
options	null	deref	return	typeinfo	this
cast	upcast	reinterpret	operator	in	scope
require	true	false	typedef	with	override
type	expect	auto	include	where	addr
assert	invoke

Keywords and types are covered in detail later in this document.

2.1.3. Operators

daScript recognizes the following operators:

!	:=	??	==	&	>=	<=	>
->	+	+=	-	-=	/	/=	*
*=	|>	<|	++	--	<-	=	&
^	|	~	>>	.	?.	??

2.1.4. Other tokens

Other significant tokens are:

{	}	[	]	.	:
::	'	;	"	]]	[[

2.1.5. Literals

daScript accepts integer numbers, unsigned integers, floating and double point numbers and string literals.

34	Integer number(base 10)
0xFF00A120	Unsigned Integer number(base 16)
0753	Integer number(base 8)
'a'	Integer number
1.52	Floating point number
1.e2	Floating point number
1.e-2	Floating point number
1.52d	Double point number
1.e2d	Double point number
1.e-2d	Double point number
"I'm a string"	String
@" I'm a multiline verbatim string "	String

Pesudo BNF

IntegerLiteral        ::=  [1-9][0-9]* | '0x' [0-9A-Fa-f]+ | ''' [.]+ ''' | 0[0-7]+
FloatLiteral          ::=  [0-9]+ '.' [0-9]+
FloatLiteral          ::=  [0-9]+ '.' 'e'|'E' '+'|'-' [0-9]+
StringLiteral         ::=  '"'[.]* '"'
VerbatimStringLiteral ::=  '@''"'[.]* '"'

2.1.6. Comments

A comment is text that the compiler ignores but that is useful for programmers. Comments are normally used to embed annotations in the code. The compiler treats them as white space.

A comment can be /* (slash, asterisk) characters, followed by any sequence of characters (including new lines), followed by the */ characters. This syntax is the same as ANSI C:

/*
This is
a multiline comment.
This lines will be ignored by the compiler.
*/

A comment can also be // (two slashes) characters, followed by any sequence of characters. A new line not immediately preceded by a backslash terminates this form of comment. It is commonly called a “single-line comment.”:

// This is a single line comment. This line will be ignored by the compiler.

2.1.7. Semantic indenting

daScript follows semantic indenting (much like Python). That means, that logical blocks are arranged with a same indenting, and if control statement requires nesting of block (such as body of function, block, if, for, etc.) it have to be indented one step more. Indenting step is part of options of program, so it is either 2, 4 or 8, but always the same for whole file. Default indenting is 4, and can be globally overriden per project.