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]). Daslang 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 as keywords and cannot be used as identifiers:

struct	class	let	def	while	if
static_if	else	for	recover	true	false
new	typeinfo	type	in	is	as
elif	static_elif	array	return	null	break
try	options	table	expect	const	require
operator	enum	finally	delete	deref	aka
typedef	with	cast	override	abstract	upcast
iterator	var	addr	continue	where	pass
reinterpret	module	public	label	goto	implicit
shared	private	smart_ptr	generator	yield	unsafe
assume	explicit	sealed	static	inscope	fixed_array
typedecl	capture	default	uninitialized		template

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

bool	void	string	auto	int	int2
int3	int4	uint	bitfield	uint2	uint3
uint4	float	float2	float3	float4	range
urange	block	int64	uint64	double	function
lambda	int8	uint8	int16	uint16	tuple
variant	range64	urange64

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

2.1.3. Operators

Daslang recognizes the following operators:

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

2.1.4. Other tokens

Other significant tokens are:

{	}	[	]	.	:
::	'	;	"	]]	[[
[{	}]	{{	}}	@	$
#

2.1.5. Literals

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

34	Integer number(base 10)
0xFF00A120	Unsigned Integer number(base 16)
13l	Long Integer number(base 10)
0xFF00A120ul	Long Unsigned Integer number(base 16)
32u8	Unsigned 8-byte integer
'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.e2lf	Double point number
1.e-2d	Double point number
"I'm a string"	String
" I'm a multiline verbatim string "	String

Pseudo 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 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 slash) 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 and Significant White Space

Daslang in gen2 automatically places semicolumns inside the code, enclosed with a curly bracers; unless its also enclosed in any type of brackets:

def foo {
    var a = 0       // das lang will add ; here
    var b = 1;      // redundant ;
    var c = ( 1     // no automatic ; here
        + 2 ) * 3;  // redundant ;
}

Daslang in gen1 sytnax follows semantic indenting (much like Python). That means that logical blocks are arranged with the same indenting, and if a control statement requires the nesting of a block (such as the body of a function, block, if, for, etc.), it has to be indented one step more. The indenting step is part of the options of the program. It is either 2, 4 or 8, but always the same for whole file. The default indenting is 4, but can be globally overridden per project.