Lexical Structure

Keywords

• Directives/Declarators: import class, struct, enum, interface, mixin, unittest, alias, thread, function, method, operator, let, var
• Access Control: public, private, module, package
• Storage Classes: meta, ref, out, scope
• Control Flow: for, loop, break, continue, return, throw, try, catch, if, else, switch, case, default, defer
• Built-In Values: this, super, null, true, false
• Basic Types: type, void, bool, byte, ubyte, short, ushort, int, uint, long, ulong, __size, __sizediff, float, double, real, char, wchar, dchar, noreturn
• Typeof Expression: typeof
• Type Qualifiers: isolated, escape, immutable, const, shared, synchronized
• Type Casting: cast

Punctuation

• Operators: &&, ||, ?, !, ~, +, -, *, /, %, &, |, ^, ^^, <<, >>, =, +=, -=, *=, /=, %=, &=, |=, ^=, ~=, ^^=, <<=, >>=, ++, --, ==, !=, <=, <, >, >=, <>, is, !is, =>, [, ], ..
• Delimiters: ., :, ,, ;, (, ), {, }
• Other: $, #, @, ...

Identifiers

Identifiers must start with an alphabetic Unicode character or with an underscore (_) and can contain any number of alpanumeric characters and underscores. An identifier cannot be identical to one of the keywords listed above.

Identifiers starting with two consecutive underscores (__) are reserved to the language/runtime implementation and should not be used for user defined symbols. Unless explicitly specified, the name of symbols starting with two underscores is implementation defined.

Constant Literals

• true: Value of type bool equivalent to one
• false: Value of type bool equivalent to zero
• null: Value of type typeof(null) representing a pointer to the zero address, which is equivalent to a pointer to "nothing"

Numeric Literals

The following types of numeric literals are available:

• Decimal Integers:

  These consist of either a single zero (0), or a non-zero digit followed by zero or more digits.

• Hexadecimal Integers:

  Hexadecimal integers start with a 0x sequence, followed by at least one decimal digit or an upper or lower case letter from "a" to "f".

  Example: 0x1F

• Decimal Floating-Point Numbers:

  Follows the C formatting of floating-point numbers. An optional 'f' suffix can be used to force the type of the literal to float, rather than the default double.

  Examples: 1.2e-3, 3.1415f

String Literals

• Double Quoted Strings:

  Escaped strings are the default string type, delimited by double-quotes. They support C-style escape sequences, as well as Unicode escape sequences.

  Example: "This is a string\nwith two lines. Smiley: \u1F600"

  In addition to escape sequences, double quoted strings also support string interpolation sequences started by $(, followed by an arbitrary expression and terminated by a matching ).

  Example: "The time is $(getTime())."

• RAW Strings:

  Raw strings are arbitrary character sequences delimited by a backtick character. No escaping or string interpolation is performed on the contained character sequence.