Syntax Conventions

Tokens

There are four types of tokens:

• identifiers
• constants
• operators
• separators

Sometimes white space is used to separate the tokens. White space is blank, horizontal tabs, vertical tabs, newlines, formfeeds and comments.

Comments

The characters // start a comment. The comment ends at the end-of-line character (\n).

Identifiers

An identifier is a sequence of characters. The first character must be a letter or the special character $. All other characters in the sequence can be letters or digits. Upper- and lower-case characters are not the same.

Constants

There are three basic types of constants:

• integer-constants
• double-constants
• string-constants

Integer-Constants

A base ten (decimal) integer-constant is a sequence of digits (example: 4711, 0815)

A base two (binary) integer-constant is a sequence which consists of the characters 0,1 preceded by a 0b or 0B (example: 0b101010)

A base sixteen (hexadecimal) integer-constant is a sequence which consists of the characters 0,1,2..9,a..f,A..F preceded by a 0x or 0X (example: 0xff or 0X2A)

Double-Constants

A double-constant is divided in an integer part, a decimal point, a fraction part, a character e or E and a signed integer exponent. The integer and fraction parts are sequences of decimal digits. (examples: 0.5, 0.333E20)

String-Constants

A string-constant starts with a double quote and ends with a double quote (example: "Hello World").

The fraction-constants, complexdouble-constants and the complex-constants are derived from the basic constants.

Fraction-Constants

A fraction-constant is an expression like:

integer-constant / integer-constant

(example: 1/3, 1/10)

Complex-Constants

A complex-constant is an expression like:

fraction-constant or integer-constant + fraction-constant or integer-constant * I

(examples: I, 3*I, 2+1/3*I )

ComplexDouble-Constants

A complexdouble-constant is an expression like:

double-constant + double-constant * I

(examples: I*1.0, 3.0*I, 2.0+0.333*I )

Expressions

There are five categories of expressions:

• constants
• strings
• symbols
• patterns
• functions

Constants and strings are described in the token-section.

Symbols

A symbol is an identifier. Symbols can represent symbolic constants (examples: E, Pi, True, False), variables (examples: x, y, z) or functionnames (examples: f, Sin, Cos, Multiply). Symbols can have attributes like (Listable, Flat, Orderless, OneIdentity, HoldFirst, HoldRest, HoldAll). Attributes can be set for a symbol with the function SetAttributes.

Patterns

A pattern is a symbol with an appended _ (underline character) (examples: x_, y_, i_).

Functions

A function is a symbol followed by parantheses containing a possibly empty, comma-separated list of expressions (examples: Sin(0), f(x,y), List()). The list of expressions represent the function arguments.

The following functions can be used for procedural programming:

Break, Continue, Do, If, Return, Switch, While,

The following functions can additionally be written in operator notation: