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 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

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

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 overridden per project.