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Polish notation - Definition and Overview |
| Related Words: Accent, Addition, Alphabet, Annotation, Approximation, Arrangement, Art, Bar, Bit, Blueprint, Cancel, Character, Characterization, Characters, Chart, Choreography, Cipher, Code, Comment, Commentary |
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Polish notation, also known as prefix notation was created by Jan Łukasiewicz. Operators are placed before operands.
+ 1 2
Yields (as expected) 3.
It is not limited to only two values, nor to just addition.
(* (+ 0 1) (+ 2 3))
Returns 5.
While the examples above use parantheses, one of the benefits of Polish notation is that, assuming the arity of each operator is known, parentheses are unnecessary: the order of operations is unique and easy to determine, if the expression is known to be correct. For example, assuming * and + are binary,
* + 0 1 + 2 3
can refer only to
(* (+ 0 1) (+ 2 3))
Polish notation is used in computer programming languages Lisp, Scheme (based on Lisp), and some others.
See also
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