productionset

$Revision: 1.3 $

$Date: 2002/06/12 11:18:29 $

productionset — A set of EBNF productions

Synopsis

Content Model

productionset ::=
((title,titleabbrev?)?,
 (production|productionrecap)+)

Attributes

Common attributes

Description

This element is only available if you are using the EBNF Module.

A ProductionSet is a collection of Extended Backus-Naur Form (EBNF) Productions.

EBNF is a notation for describing the grammar of context-free languages. Even if you aren't conversant in the programming language concepts of context-free languages and grammars, it's not really as hard to understand as it sounds.

A set of EBNF productions describes the legal arrangements of tokens in a language. Consider arithmetic expressions as a simple example.

The expression “3 + 4” is valid and so is “3 + 4 - 5”, but “3 - + - 4” is not, nor is “3 + 4 6”. We can use EBNF to describe all the possible legal arrangements:

Arithemetic Expressions

[1]	Expression	`::=`	ArithExpression \| MultExpression	/* Does this grammar actually get precedence right? */
[2]	ArithExpression	`::=`	Expression '+' MultExpression \| Expression '-' MultExpression
[3]	MultExpression	`::=`	MultExpression '*' MultExpression \| MultExpression '/' MultExpression \| Number	[ Err: Division by Zero ]
[4]	Number	`::=`	[0-9]+

Division by Zero

Division by zero is an error. Constraints, such as this one, are used to express conditions that cannot be expressed in the grammar.

Processing expectations

Formatted as a displayed block. The detailed processing expecations with respect to individual productions, left-hand sides, and right-hand sides are quite complex.

Productions should be numbered.

Parents

These elements contain productionset: appendix, article, bibliodiv, bibliography, blockquote, callout, chapter, glossary, glossdiv, index, listitem, msgexplan, msgtext, partintro, preface, procedure, refsect1, refsect2, refsect3, refsection, refsynopsisdiv, sect1, sect2, sect3, sect4, sect5, section, setindex, simplesect, step, taskprerequisites, taskrelated, tasksummary.

Children

The following elements occur in productionset: production, productionrecap, title, titleabbrev.

Examples

<!DOCTYPE simplesect PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
          "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
<simplesect><title>EBNF Grammar</title>

<productionset><title>Arithemetic Expressions</title>
<production id="ebnf.expression">
  <lhs>Expression</lhs>
  <rhs><nonterminal def="#ebnf.arith">ArithExpression</nonterminal> |
       <nonterminal def="#ebnf.mult">MultExpression</nonterminal>
  <lineannotation>Does this grammar actually get precedence right?
  </lineannotation>
  </rhs>
</production>
<production id="ebnf.arith">
  <lhs>ArithExpression</lhs>
  <rhs><nonterminal def="#ebnf.expression">Expression</nonterminal>
       '+'
       <nonterminal def="#ebnf.mult">MultExpression</nonterminal> |
       <nonterminal def="#ebnf.expression">Expression</nonterminal>
       '-'
       <nonterminal def="#ebnf.mult">MultExpression</nonterminal>
  </rhs>
</production>
<production id="ebnf.mult">
  <lhs>MultExpression</lhs>
  <rhs><nonterminal def="#ebnf.mult">MultExpression</nonterminal>
       '*'
       <nonterminal def="#ebnf.mult">MultExpression</nonterminal> |
       <nonterminal def="#ebnf.mult">MultExpression</nonterminal>
       '/'
       <nonterminal def="#ebnf.mult">MultExpression</nonterminal> |
       <nonterminal def="#ebnf.number">Number</nonterminal>
  </rhs>
  <constraint linkend="div0"/>
</production>
<production id="ebnf.number">
  <lhs>Number</lhs>
  <rhs>[0-9]+</rhs>
</production>
</productionset>

<constraintdef id="div0">
<title>Division by Zero</title>
<para>Division by zero is an error.</para>
</constraintdef>
</simplesect>


productionrecap		productname