Editing Polish notation (section)

==Implementations==
Prefix notation has seen wide application in [[Lisp (programming language)|Lisp]] [[S-expressions]], where the parentheses are required since the operators in the language are themselves data ([[first-class function]]s). Lisp functions may also be [[Variadic function|variadic]]. The [[Tcl]] programming language, much like Lisp also uses Polish notation through the mathop library. The Ambi<ref name="Ambi"/> programming language uses Polish notation for arithmetic operations and program construction. [[LDAP]] filter syntax uses Polish prefix notation.<ref name="LDAPSyntax"/>

Postfix notation is used in many [[stack-oriented programming language]]s like [[PostScript]] and [[Forth (programming language)|Forth]]. [[CoffeeScript]] syntax also allows functions to be called using prefix notation, while still supporting the unary postfix syntax common in other languages.

The number of return values of an expression equals the difference between the number of operands in an expression and the total arity of the operators minus the total number of return values of the operators.

Polish notation, usually in postfix form, is the chosen notation of certain [[calculator]]s, notably from [[HP calculators|Hewlett-Packard]].<ref name="RPN_HP35S"/> At a lower level, postfix operators are used by some [[stack machines]] such as the [[Burroughs large systems]].