BNF - Backus Normal Form
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Last update
2016-07-02
2016
07-02
«Come scrivere definizioni»

BNF is one of the two main notation techniques for context-free grammars.

Example:

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A sandwich consists of a lower slice of bread, mustard or mayonnaise;
optional lettuce, an optional slice of tomato; two to four slices of
either bologna, salami, or ham (in any combination); one or more slices
of cheese, and a top slice of bread.

This translates to:

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sandwich ::= lower_slice [mustard|mayonnaise] lettuce? tomato?
             [bologna|salami|ham]{2,4} cheese+ top_slice

References: AListApart, Wikipedia