![[EBNF]](figures/rev_ebnf.png)
productionset
Synopsis
Content Model
productionset ::= ((title,titleabbrev?)?, (production|productionrecap)+)
Attributes
Parameter Entities
The following parameter entities contain productionset:
| Parameter Entities | ||
| %bookcomponent.content; | %component.mix; | %compound.class; |
| %divcomponent.mix; | %ebnf.block.hook; | %refcomponent.mix; |
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 | ||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
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, refsynopsisdiv, sect1, sect2, sect3, sect4, sect5, section, setindex, simplesect, step.
Children
The following elements occur in productionset: production, productionrecap, title, titleabbrev.
Examples
<!DOCTYPE productionset PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
<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>