View Source: BackusNaurForm - Waikato Linux Users Group

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This is a language to define the formal grammar of a language, whether that be a ProgrammingLanguage, a MarkupLanguage or simply the syntax of a configuration file.

An example grammar would be

 <sentance> ::= <verb-part> <noun-part>

 <verb-part> ::= <noun-part> <verb>

 <noun-part> ::= <proper-noun>
               | THE <noun>

 <verb> ::= throws
          | kicks
          | hides
          | fetches

 <proper-noun> ::= John
                 | Jane

 <noun> ::= ball
        ::= dog

This grammar accepts sentances such as
* Jane throws the ball
* The dog fetches the ball
* John kicks the dog
* John hides Jane
* The ball fetches Jane

but would not accept sentences such as
* John deflates the ball
* Jane hides in the basement

because __deflates__ is not a verb known in this grammer and __in the basement__ is not a noun. The grammar would have to be extended to cover such cases.

Because some common cases are inconvenient to define using pure [BNF], some extensions have been added in [EBNF]:
*  __...__ means ''1 or more''
* __[[ ]__ means ''optional''

3 pages link to BackusNaurForm:

Last edited on Saturday, August 23, 2003 10:07:24 am by AristotlePagaltzis

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