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BNF
nonterm
BNF-seq
BNF-group
optional
kleenestar
kleeneplus
kleenerange
BNF-alt
BNF-etc
Version: 4.1

13 BNF Grammars

 (require scribble/bnf)

The scribble/bnf library provides utilities for typesetting grammars.

See also schemegrammar.

(BNF prod ...)  table?

  prod : (cons element? (listof element?))

Typesets a grammar table. Each production starts with an element (typically constructed with nonterm) for the non-terminal being defined, and then a list of possibilities (typically constructed with BNF-seq, etc.) to show on separate lines.

(nonterm pre-content ...)  element?

  pre-content : any/c

Typesets a non-terminal: italic in angle brackets.

(BNF-seq elem ...)  element?

  elem : element?

Typesets a sequence.

(BNF-group pre-content ...)  element?

  pre-content : any/c

Typesets a group surrounded by curly braces (so the entire group can be repeated, for example).

(optional pre-content ...)  element?

  pre-content : any/c

Typesets an optional element: in square brackets.

(kleenestar pre-content ...)  element?

  pre-content : any/c

Typesets a 0-or-more repetition.

(kleeneplus pre-content ...)  element?

  pre-content : any/c

Typesets a 1-or-more repetition.

(kleenerange n m pre-content ...)  element?

  n : any/c

  m : any/c

  pre-content : any/c

Typesets a n-to-m repetition. The n and m arguments are converted to a string using (format "~a" n) and (format "~a" m).

(BNF-alt elem ...)  element?

  elem : element?

Typesets alternatives for a production’s right-hand side to appear on a single line. The result is normally used as a single possibility in a production list for BNF.

BNF-etc : string?

A string to use for omitted productions or content.