productionset
productionset — A set of EBNF productions.
Synopsis
productionset ::=
Attributes
Additional Constraints
- If this element is the root element, it must have a version attribute.
Description
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.
Processing expectations
Formatted as a displayed block. The detailed processing expectations with respect to individual productions, lefthand sides, and righthand sides are quite complex.
The productions should be numbered.
Parents
These elements contain productionset: acknowledgements, annotation, answer, appendix, article, bibliodiv, bibliography, bibliolist, blockquote, callout, calloutlist, caption (db.caption), caution, chapter, colophon, constraintdef, cover, dedication, entry, example, figure, footnote, glossary, glossdef, glossdiv, glosslist, important, index, indexdiv, informalexample, informalfigure, itemizedlist, legalnotice, listitem, msgexplan, msgtext, note, orderedlist, para, partintro, preface, procedure, qandadiv, qandaset, question, refsect1, refsect2, refsect3, refsection, refsynopsisdiv, result, revdescription, sect1, sect2, sect3, sect4, sect5, section, setindex, sidebar, simplesect, step, taskprerequisites, taskrelated, tasksummary, td, textobject, th, tip, toc, tocdiv, topic, variablelist, warning.
Children
The following elements occur in productionset: info (db.titleforbidden.info), info (db.titleonly.info), production, productionrecap, title, titleabbrev.
Examples
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:
Division by zero is an error.
</constraintdef>That is expressed in DocBook like this:
<article xmlns='http://docbook.org/ns/docbook'>
<title>Example productionset</title>
<simplesect><title>EBNF Grammar</title>
<productionset><title>Arithemetic Expressions</title>
<production xml: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 xml: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 xml: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 xml:id="ebnf.number">
<lhs>Number</lhs>
<rhs>[0-9]+</rhs>
</production>
</productionset>
<constraintdef xml:id="div0">
<title>Division by Zero</title>
<para>Division by zero is an error.</para>
</constraintdef>
</simplesect>
</article>