-<!-- $Id: tools.xml,v 1.16 2003-01-23 20:26:37 adam Exp $ -->
+<!-- $Id: tools.xml,v 1.54 2006-10-31 09:15:00 mike Exp $ -->
<chapter id="tools"><title>Supporting Tools</title>
<para>
<token>Z_RPNQuery</token> structure. Some programmers will prefer to
construct the query manually, perhaps using
<function>odr_malloc()</function> to simplify memory management.
- The &yaz; distribution includes two separate, query-generating tools
+ The &yaz; distribution includes three separate, query-generating tools
that may be of use to you.
</para>
top-set ::= [ '@attrset' string ]
- query-struct ::= attr-spec | simple | complex | '@term' term-type
+ query-struct ::= attr-spec | simple | complex | '@term' term-type query
attr-spec ::= '@attr' [ string ] string query-struct
<para>
The @attr operator is followed by an attribute specification
(<literal>attr-spec</literal> above). The specification consists
- of optional an attribute set, an attribute type-value pair and
- a sub query. The attribute type-value pair is packed in one string:
- an attribute type, a dash, followed by an attribute value.
+ of an optional attribute set, an attribute type-value pair and
+ a sub-query. The attribute type-value pair is packed in one string:
+ an attribute type, an equals sign, and an attribute value, like this:
+ <literal>@attr 1=1003</literal>.
The type is always an integer but the value may be either an
integer or a string (if it doesn't start with a digit character).
+ A string attribute-value is encoded as a Type-1 ``complex''
+ attribute with the list of values containing the single string
+ specified, and including no semantic indicators.
</para>
<para>
- Z39.50 version 3 defines various encoding of terms.
- Use the @term operator to indicate the encoding type:
- <literal>general</literal>, <literal>numeric</literal>,
- <literal>string</literal> (for InternationalString), ..
+ Version 3 of the Z39.50 specification defines various encoding of terms.
+ Use <literal>@term </literal> <replaceable>type</replaceable>
+ <replaceable>string</replaceable>,
+ where type is one of: <literal>general</literal>,
+ <literal>numeric</literal> or <literal>string</literal>
+ (for InternationalString).
If no term type has been given, the <literal>general</literal> form
- is used which is the only encoding allowed in both version 2 - and 3
+ is used. This is the only encoding allowed in both versions 2 and 3
of the Z39.50 standard.
</para>
- <para>
- The following are all examples of valid queries in the PQF.
- </para>
-
- <screen>
- dylan
-
- "bob dylan"
-
- @or "dylan" "zimmerman"
-
- @set Result-1
-
- @or @and bob dylan @set Result-1
-
- @attr 1=4 computer
-
- @attr 4=1 @and @attr 1=1 "bob dylan" @attr 1=4 "slow train coming"
-
- @attr 4=1 @attr 1=4 "self portrait"
-
- @prox 0 3 1 2 k 2 dylan zimmerman
-
- @and @attr 2=4 @attr gils 1=2038 -114 @attr 2=2 @attr gils 1=2039 -109
-
- @term string "a UTF-8 string, maybe?"
-
- @attr 1=/book/title computer
- </screen>
+ <sect3 id="PQF-prox">
+ <title>Using Proximity Operators with PQF</title>
+ <note>
+ <para>
+ This is an advanced topic, describing how to construct
+ queries that make very specific requirements on the
+ relative location of their operands.
+ You may wish to skip this section and go straight to
+ <link linkend="pqf-examples">the example PQF queries</link>.
+ </para>
+ <para>
+ <warning>
+ <para>
+ Most Z39.50 servers do not support proximity searching, or
+ support only a small subset of the full functionality that
+ can be expressed using the PQF proximity operator. Be
+ aware that the ability to <emphasis>express</emphasis> a
+ query in PQF is no guarantee that any given server will
+ be able to <emphasis>execute</emphasis> it.
+ </para>
+ </warning>
+ </para>
+ </note>
+ <para>
+ The proximity operator <literal>@prox</literal> is a special
+ and more restrictive version of the conjunction operator
+ <literal>@and</literal>. Its semantics are described in
+ section 3.7.2 (Proximity) of Z39.50 the standard itself, which
+ can be read on-line at
+ <ulink url="&url.z39.50.proximity;"/>
+ </para>
+ <para>
+ In PQF, the proximity operation is represented by a sequence
+ of the form
+ <screen>
+@prox <replaceable>exclusion</replaceable> <replaceable>distance</replaceable> <replaceable>ordered</replaceable> <replaceable>relation</replaceable> <replaceable>which-code</replaceable> <replaceable>unit-code</replaceable>
+ </screen>
+ in which the meanings of the parameters are as described in in
+ the standard, and they can take the following values:
+ <itemizedlist>
+ <listitem><formalpara><title>exclusion</title><para>
+ 0 = false (i.e. the proximity condition specified by the
+ remaining parameters must be satisfied) or
+ 1 = true (the proximity condition specified by the
+ remaining parameters must <emphasis>not</emphasis> be
+ satisifed).
+ </para></formalpara></listitem>
+ <listitem><formalpara><title>distance</title><para>
+ An integer specifying the difference between the locations
+ of the operands: e.g. two adjacent words would have
+ distance=1 since their locations differ by one unit.
+ </para></formalpara></listitem>
+ <listitem><formalpara><title>ordered</title><para>
+ 1 = ordered (the operands must occur in the order the
+ query specifies them) or
+ 0 = unordered (they may appear in either order).
+ </para></formalpara></listitem>
+ <listitem><formalpara><title>relation</title><para>
+ Recognised values are
+ 1 (lessThan),
+ 2 (lessThanOrEqual),
+ 3 (equal),
+ 4 (greaterThanOrEqual),
+ 5 (greaterThan) and
+ 6 (notEqual).
+ </para></formalpara></listitem>
+ <listitem><formalpara><title>which-code</title><para>
+ <literal>known</literal>
+ or
+ <literal>k</literal>
+ (the unit-code parameter is taken from the well-known list
+ of alternatives described in below) or
+ <literal>private</literal>
+ or
+ <literal>p</literal>
+ (the unit-code paramater has semantics specific to an
+ out-of-band agreement such as a profile).
+ </para></formalpara></listitem>
+ <listitem><formalpara><title>unit-code</title><para>
+ If the which-code parameter is <literal>known</literal>
+ then the recognised values are
+ 1 (character),
+ 2 (word),
+ 3 (sentence),
+ 4 (paragraph),
+ 5 (section),
+ 6 (chapter),
+ 7 (document),
+ 8 (element),
+ 9 (subelement),
+ 10 (elementType) and
+ 11 (byte).
+ If which-code is <literal>private</literal> then the
+ acceptable values are determined by the profile.
+ </para></formalpara></listitem>
+ </itemizedlist>
+ (The numeric values of the relation and well-known unit-code
+ parameters are taken straight from
+ <ulink url="&url.z39.50.proximity.asn1;"
+ >the ASN.1</ulink> of the proximity structure in the standard.)
+ </para>
+ </sect3>
+ <sect3 id="pqf-examples"><title>PQF queries</title>
+
+ <example id="example.pqf.simple.terms">
+ <title>PQF queries using simple terms</title>
+ <para>
+ <screen>
+ dylan
+
+ "bob dylan"
+ </screen>
+ </para>
+ </example>
+ <example id="pqf.example.pqf.boolean.operators">
+ <title>PQF boolean operators</title>
+ <para>
+ <screen>
+ @or "dylan" "zimmerman"
+
+ @and @or dylan zimmerman when
+
+ @and when @or dylan zimmerman
+ </screen>
+ </para>
+ </example>
+ <example id="example.pqf.result.sets">
+ <title>PQF references to result sets</title>
+ <para>
+ <screen>
+ @set Result-1
+
+ @and @set seta @set setb
+ </screen>
+ </para>
+ </example>
+ <example id="example.pqf.attributes">
+ <title>Attributes for terms</title>
+ <para>
+ <screen>
+ @attr 1=4 computer
+
+ @attr 1=4 @attr 4=1 "self portrait"
+
+ @attrset exp1 @attr 1=1 CategoryList
+
+ @attr gils 1=2008 Copenhagen
+
+ @attr 1=/book/title computer
+ </screen>
+ </para>
+ </example>
+ <example id="example.pqf.proximity">
+ <title>PQF Proximity queries</title>
+ <para>
+ <screen>
+ @prox 0 3 1 2 k 2 dylan zimmerman
+ </screen>
+ <note><para>
+ Here the parameters 0, 3, 1, 2, k and 2 represent exclusion,
+ distance, ordered, relation, which-code and unit-code, in that
+ order. So:
+ <itemizedlist>
+ <listitem><para>
+ exclusion = 0: the proximity condition must hold
+ </para></listitem>
+ <listitem><para>
+ distance = 3: the terms must be three units apart
+ </para></listitem>
+ <listitem><para>
+ ordered = 1: they must occur in the order they are specified
+ </para></listitem>
+ <listitem><para>
+ relation = 2: lessThanOrEqual (to the distance of 3 units)
+ </para></listitem>
+ <listitem><para>
+ which-code is ``known'', so the standard unit-codes are used
+ </para></listitem>
+ <listitem><para>
+ unit-code = 2: word.
+ </para></listitem>
+ </itemizedlist>
+ So the whole proximity query means that the words
+ <literal>dylan</literal> and <literal>zimmerman</literal> must
+ both occur in the record, in that order, differing in position
+ by three or fewer words (i.e. with two or fewer words between
+ them.) The query would find ``Bob Dylan, aka. Robert
+ Zimmerman'', but not ``Bob Dylan, born as Robert Zimmerman''
+ since the distance in this case is four.
+ </para></note>
+ </para>
+ </example>
+ <example id="example.pqf.search.term.type">
+ <title>PQF specification of search term type</title>
+ <para>
+ <screen>
+ @term string "a UTF-8 string, maybe?"
+ </screen>
+ </para>
+ </example>
+ <example id="example.pqf.mixed.queries">
+ <title>PQF mixed queries</title>
+ <para>
+ <screen>
+ @or @and bob dylan @set Result-1
+
+ @attr 4=1 @and @attr 1=1 "bob dylan" @attr 1=4 "slow train coming"
+
+ @and @attr 2=4 @attr gils 1=2038 -114 @attr 2=2 @attr gils 1=2039 -109
+ </screen>
+ <note>
+ <para>
+ The last of these examples is a spatial search: in
+ <ulink url="http://www.gils.net/prof_v2.html#sec_7_4"
+ >the GILS attribute set</ulink>,
+ access point
+ 2038 indicates West Bounding Coordinate and
+ 2030 indicates East Bounding Coordinate,
+ so the query is for areas extending from -114 degrees
+ to no more than -109 degrees.
+ </para>
+ </note>
+ </para>
+ </example>
+ </sect3>
</sect2>
- <sect2 id="CCL"><title>Common Command Language</title>
+ <sect2 id="CCL"><title>CCL</title>
<para>
Not all users enjoy typing in prefix query structures and numerical
attribute values, even in a minimalistic test client. In the library
- world, the more intuitive Common Command Language (or ISO 8777) has
- enjoyed some popularity - especially before the widespread
+ world, the more intuitive Common Command Language - CCL (ISO 8777)
+ has enjoyed some popularity - especially before the widespread
availability of graphical interfaces. It is still useful in
applications where you for some reason or other need to provide a
symbolic language for expressing boolean query structures.
</para>
<para>
- The <ulink url="http://europagate.dtv.dk/">EUROPAGATE</ulink>
- research project working under the Libraries programme
+ The EUROPAGATE research project working under the Libraries programme
of the European Commission's DG XIII has, amongst other useful tools,
implemented a general-purpose CCL parser which produces an output
structure that can be trivially converted to the internal RPN
license, it is included as a supplement to &yaz;.
</para>
- <sect3><title>CCL Syntax</title>
+ <sect3 id="ccl.syntax">
+ <title>CCL Syntax</title>
<para>
The CCL parser obeys the following grammar for the FIND argument.
-- Proximity operator
</screen>
-
- <para>
- The following queries are all valid:
- </para>
-
- <screen>
- dylan
-
- "bob dylan"
-
- dylan or zimmerman
-
- set=1
-
- (dylan and bob) or set=1
-
- </screen>
- <para>
- Assuming that the qualifiers <literal>ti</literal>, <literal>au</literal>
- and <literal>date</literal> are defined we may use:
- </para>
-
- <screen>
- ti=self portrait
-
- au=(bob dylan and slow train coming)
-
- date>1980 and (ti=((self portrait)))
-
- </screen>
-
+
+ <example id="example.ccl.queries">
+ <title>CCL queries</title>
+ <para>
+ The following queries are all valid:
+ </para>
+
+ <screen>
+ dylan
+
+ "bob dylan"
+
+ dylan or zimmerman
+
+ set=1
+
+ (dylan and bob) or set=1
+
+ </screen>
+ <para>
+ Assuming that the qualifiers <literal>ti</literal>,
+ <literal>au</literal>
+ and <literal>date</literal> are defined we may use:
+ </para>
+
+ <screen>
+ ti=self portrait
+
+ au=(bob dylan and slow train coming)
+
+ date>1980 and (ti=((self portrait)))
+
+ </screen>
+ </example>
+
</sect3>
- <sect3><title>CCL Qualifiers</title>
-
+ <sect3 id="ccl.qualifiers">
+ <title>CCL Qualifiers</title>
+
<para>
Qualifiers are used to direct the search to a particular searchable
index, such as title (ti) and author indexes (au). The CCL standard
suggest a few short-hand notations. You can customize the CCL parser
to support a particular set of qualifiers to reflect the current target
profile. Traditionally, a qualifier would map to a particular
- use-attribute within the BIB-1 attribute set. However, you could also
- define qualifiers that would set, for example, the
- structure-attribute.
- </para>
-
- <para>
- Consider a scenario where the target support ranked searches in the
- title-index. In this case, the user could specify
- </para>
-
- <screen>
- ti,ranked=knuth computer
- </screen>
- <para>
- and the <literal>ranked</literal> would map to relation=relevance
- (2=102) and the <literal>ti</literal> would map to title (1=4).
- </para>
-
- <para>
- A "profile" with a set predefined CCL qualifiers can be read from a
- file. The YAZ client reads its CCL qualifiers from a file named
- <filename>default.bib</filename>. Each line in the file has the form:
- </para>
-
- <para>
- <replaceable>qualifier-name</replaceable>
- <replaceable>type</replaceable>=<replaceable>val</replaceable>
- <replaceable>type</replaceable>=<replaceable>val</replaceable> ...
- </para>
-
- <para>
- where <replaceable>qualifier-name</replaceable> is the name of the
- qualifier to be used (eg. <literal>ti</literal>),
- <replaceable>type</replaceable> is a BIB-1 category type and
- <replaceable>val</replaceable> is the corresponding BIB-1 attribute
- value.
- The <replaceable>type</replaceable> can be either numeric or it may be
- either <literal>u</literal> (use), <literal>r</literal> (relation),
- <literal>p</literal> (position), <literal>s</literal> (structure),
- <literal>t</literal> (truncation) or <literal>c</literal> (completeness).
- The <replaceable>qualifier-name</replaceable> <literal>term</literal>
- has a special meaning.
- The types and values for this definition is used when
- <emphasis>no</emphasis> qualifiers are present.
+ use-attribute within the BIB-1 attribute set. It is also
+ possible to set other attributes, such as the structure
+ attribute.
</para>
<para>
- Consider the following definition:
+ A CCL profile is a set of predefined CCL qualifiers that may be
+ read from a file or set in the CCL API.
+ The YAZ client reads its CCL qualifiers from a file named
+ <filename>default.bib</filename>. There are four types of
+ lines in a CCL profile: qualifier specification,
+ qualifier alias, comments and directives.
</para>
-
- <screen>
- ti u=4 s=1
- au u=1 s=1
- term s=105
- </screen>
- <para>
- Two qualifiers are defined, <literal>ti</literal> and
- <literal>au</literal>.
- They both set the structure-attribute to phrase (1).
- <literal>ti</literal>
- sets the use-attribute to 4. <literal>au</literal> sets the
- use-attribute to 1.
- When no qualifiers are used in the query the structure-attribute is
- set to free-form-text (105).
- </para>
-
+ <sect4 id="ccl.qualifier.specification">
+ <title>Qualifier specification</title>
+ <para>
+ A qualifier specification is of the form:
+ </para>
+
+ <para>
+ <replaceable>qualifier-name</replaceable>
+ [<replaceable>attributeset</replaceable><literal>,</literal>]<replaceable>type</replaceable><literal>=</literal><replaceable>val</replaceable>
+ [<replaceable>attributeset</replaceable><literal>,</literal>]<replaceable>type</replaceable><literal>=</literal><replaceable>val</replaceable> ...
+ </para>
+
+ <para>
+ where <replaceable>qualifier-name</replaceable> is the name of the
+ qualifier to be used (eg. <literal>ti</literal>),
+ <replaceable>type</replaceable> is attribute type in the attribute
+ set (Bib-1 is used if no attribute set is given) and
+ <replaceable>val</replaceable> is attribute value.
+ The <replaceable>type</replaceable> can be specified as an
+ integer or as it be specified either as a single-letter:
+ <literal>u</literal> for use,
+ <literal>r</literal> for relation,<literal>p</literal> for position,
+ <literal>s</literal> for structure,<literal>t</literal> for truncation
+ or <literal>c</literal> for completeness.
+ The attributes for the special qualifier name <literal>term</literal>
+ are used when no CCL qualifier is given in a query.
+ <table id="ccl.common.bib1.attributes">
+ <title>Common Bib-1 attributes</title>
+ <tgroup cols="2">
+ <colspec colwidth="2*" colname="type"></colspec>
+ <colspec colwidth="9*" colname="description"></colspec>
+ <thead>
+ <row>
+ <entry>Type</entry>
+ <entry>Description</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry><literal>u=</literal><replaceable>value</replaceable></entry>
+ <entry>
+ Use attribute (1). Common use attributes are
+ 1 Personal-name, 4 Title, 7 ISBN, 8 ISSN, 30 Date,
+ 62 Subject, 1003 Author), 1016 Any. Specify value
+ as an integer.
+ </entry>
+ </row>
+
+ <row>
+ <entry><literal>r=</literal><replaceable>value</replaceable></entry>
+ <entry>
+ Relation attribute (2). Common values are
+ 1 <, 2 <=, 3 =, 4 >=, 5 >, 6 <>,
+ 100 phonetic, 101 stem, 102 relevance, 103 always matches.
+ </entry>
+ </row>
+
+ <row>
+ <entry><literal>p=</literal><replaceable>value</replaceable></entry>
+ <entry>
+ Position attribute (3). Values: 1 first in field, 2
+ first in any subfield, 3 any position in field.
+ </entry>
+ </row>
+
+ <row>
+ <entry><literal>s=</literal><replaceable>value</replaceable></entry>
+ <entry>
+ Structure attribute (4). Values: 1 phrase, 2 word,
+ 3 key, 4 year, 5 date, 6 word list, 100 date (un),
+ 101 name (norm), 102 name (un), 103 structure, 104 urx,
+ 105 free-form-text, 106 document-text, 107 local-number,
+ 108 string, 109 numeric string.
+ </entry>
+ </row>
+
+ <row>
+ <entry><literal>t=</literal><replaceable>value</replaceable></entry>
+ <entry>
+ Truncation attribute (5). Values: 1 right, 2 left,
+ 3 left& right, 100 none, 101 process #, 102 regular-1,
+ 103 regular-2, 104 CCL.
+ </entry>
+ </row>
+
+ <row>
+ <entry><literal>c=</literal><replaceable>value</replaceable></entry>
+ <entry>
+ Completeness attribute (6). Values: 1 incomplete subfield,
+ 2 complete subfield, 3 complete field.
+ </entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+ </para>
+ <para>
+ Refer to the complete
+ <ulink url="&url.z39.50.attset.bib1;">list of Bib-1 attributes</ulink>
+ </para>
+ <para>
+ It is also possible to specify non-numeric attribute values,
+ which are used in combination with certain types.
+ The special combinations are:
+
+ <table id="ccl.special.attribute.combos">
+ <title>Special attribute combos</title>
+ <tgroup cols="2">
+ <colspec colwidth="2*" colname="name"></colspec>
+ <colspec colwidth="9*" colname="description"></colspec>
+ <thead>
+ <row>
+ <entry>Name</entry>
+ <entry>Description</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry><literal>s=pw</literal></entry><entry>
+ The structure is set to either word or phrase depending
+ on the number of tokens in a term (phrase-word).
+ </entry>
+ </row>
+ <row>
+ <entry><literal>s=al</literal></entry><entry>
+ Each token in the term is ANDed. (and-list).
+ This does not set the structure at all.
+ </entry>
+ </row>
+
+ <row><entry><literal>s=ol</literal></entry><entry>
+ Each token in the term is ORed. (or-list).
+ This does not set the structure at all.
+ </entry>
+ </row>
+
+ <row><entry><literal>r=o</literal></entry><entry>
+ Allows ranges and the operators greather-than, less-than, ...
+ equals.
+ This sets Bib-1 relation attribute accordingly (relation
+ ordered). A query construct is only treated as a range if
+ dash is used and that is surrounded by white-space. So
+ <literal>-1980</literal> is treated as term
+ <literal>"-1980"</literal> not <literal><= 1980</literal>.
+ If <literal>- 1980</literal> is used, however, that is
+ treated as a range.
+ </entry>
+ </row>
+
+ <row><entry><literal>r=r</literal></entry><entry>
+ Similar to <literal>r=o</literal> but assumes that terms
+ are non-negative (not prefixed with <literal>-</literal>).
+ Thus, a dash will always be treated as a range.
+ The construct <literal>1980-1990</literal> is
+ treated as a range with <literal>r=r</literal> but as a
+ single term <literal>"1980-1990"</literal> with
+ <literal>r=o</literal>. The special attribute
+ <literal>r=r</literal> is available in YAZ 2.0.24 or later.
+ </entry>
+ </row>
+
+ <row><entry><literal>t=l</literal></entry><entry>
+ Allows term to be left-truncated.
+ If term is of the form <literal>?x</literal>, the resulting
+ Type-1 term is <literal>x</literal> and truncation is left.
+ </entry>
+ </row>
+
+ <row><entry><literal>t=r</literal></entry><entry>
+ Allows term to be right-truncated.
+ If term is of the form <literal>x?</literal>, the resulting
+ Type-1 term is <literal>x</literal> and truncation is right.
+ </entry>
+ </row>
+
+ <row><entry><literal>t=n</literal></entry><entry>
+ If term is does not include <literal>?</literal>, the
+ truncation attribute is set to none (100).
+ </entry>
+ </row>
+
+ <row><entry><literal>t=b</literal></entry><entry>
+ Allows term to be both left&right truncated.
+ If term is of the form <literal>?x?</literal>, the
+ resulting term is <literal>x</literal> and trunctation is
+ set to both left&right.
+ </entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </para>
+ <example id="example.ccl.profile"><title>CCL profile</title>
+ <para>
+ Consider the following definition:
+ </para>
+
+ <screen>
+ ti u=4 s=1
+ au u=1 s=1
+ term s=105
+ ranked r=102
+ date u=30 r=o
+ </screen>
+ <para>
+ <literal>ti</literal> and <literal>au</literal> both set
+ structure attribute to phrase (s=1).
+ <literal>ti</literal>
+ sets the use-attribute to 4. <literal>au</literal> sets the
+ use-attribute to 1.
+ When no qualifiers are used in the query the structure-attribute is
+ set to free-form-text (105) (rule for <literal>term</literal>).
+ The <literal>date</literal> sets the relation attribute to
+ the relation used in the CCL query and sets the use attribute
+ to 30 (Bib-1 Date).
+ </para>
+ <para>
+ You can combine attributes. To Search for "ranked title" you
+ can do
+ <screen>
+ ti,ranked=knuth computer
+ </screen>
+ which will set relation=ranked, use=title, structure=phrase.
+ </para>
+ <para>
+ Query
+ <screen>
+ date > 1980
+ </screen>
+ is a valid query. But
+ <screen>
+ ti > 1980
+ </screen>
+ is invalid.
+ </para>
+ </example>
+ </sect4>
+ <sect4 id="ccl.qualifier.alias">
+ <title>Qualifier alias</title>
+ <para>
+ A qualifier alias is of the form:
+ </para>
+ <para>
+ <replaceable>q</replaceable>
+ <replaceable>q1</replaceable> <replaceable>q2</replaceable> ..
+ </para>
+ <para>
+ which declares <replaceable>q</replaceable> to
+ be an alias for <replaceable>q1</replaceable>,
+ <replaceable>q2</replaceable>... such that the CCL
+ query <replaceable>q=x</replaceable> is equivalent to
+ <replaceable>q1=x or q2=x or ...</replaceable>.
+ </para>
+ </sect4>
+
+ <sect4 id="ccl.comments">
+ <title>Comments</title>
+ <para>
+ Lines with white space or lines that begin with
+ character <literal>#</literal> are treated as comments.
+ </para>
+ </sect4>
+
+ <sect4 id="ccl.directives">
+ <title>Directives</title>
+ <para>
+ Directive specifications takes the form
+ </para>
+ <para><literal>@</literal><replaceable>directive</replaceable> <replaceable>value</replaceable>
+ </para>
+ <table id="ccl.directives.table">
+ <title>CCL directives</title>
+ <tgroup cols="3">
+ <colspec colwidth="2*" colname="name"></colspec>
+ <colspec colwidth="8*" colname="description"></colspec>
+ <colspec colwidth="1*" colname="default"></colspec>
+ <thead>
+ <row>
+ <entry>Name</entry>
+ <entry>Description</entry>
+ <entry>Default</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>truncation</entry>
+ <entry>Truncation character</entry>
+ <entry><literal>?</literal></entry>
+ </row>
+ <row>
+ <entry>field</entry>
+ <entry>Specifies how multiple fields are to be
+ combined. There are two modes: <literal>or</literal>:
+ multiple qualifier fields are ORed,
+ <literal>merge</literal>: attributes for the qualifier
+ fields are merged and assigned to one term.
+ </entry>
+ <entry><literal>merge</literal></entry>
+ </row>
+ <row>
+ <entry>case</entry>
+ <entry>Specificies if CCL operatores and qualifiers should be
+ compared with case sensitivity or not. Specify 0 for
+ case sensitive; 1 for case insensitive.</entry>
+ <entry><literal>0</literal></entry>
+ </row>
+
+ <row>
+ <entry>and</entry>
+ <entry>Specifies token for CCL operator AND.</entry>
+ <entry><literal>and</literal></entry>
+ </row>
+
+ <row>
+ <entry>or</entry>
+ <entry>Specifies token for CCL operator OR.</entry>
+ <entry><literal>or</literal></entry>
+ </row>
+
+ <row>
+ <entry>not</entry>
+ <entry>Specifies token for CCL operator NOT.</entry>
+ <entry><literal>not</literal></entry>
+ </row>
+
+ <row>
+ <entry>set</entry>
+ <entry>Specifies token for CCL operator SET.</entry>
+ <entry><literal>set</literal></entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+ </sect4>
</sect3>
- <sect3><title>CCL API</title>
+ <sect3 id="ccl.api">
+ <title>CCL API</title>
<para>
All public definitions can be found in the header file
<filename>ccl.h</filename>. A profile identifier is of type
</para>
</sect3>
</sect2>
- <sect2 id="tools.cql"><title>CQL</title>
+ <sect2 id="cql"><title>CQL</title>
<para>
- <ulink url="http://www.loc.gov/z3950/agency/zing/cql/">CQL</ulink>
+ <ulink url="&url.cql;">CQL</ulink>
- Common Query Language - was defined for the
- <ulink url="http://www.loc.gov/z3950/agency/zing/srw/">SRW</ulink>
- protocol.
+ <ulink url="&url.sru;">SRU</ulink> protocol.
In many ways CQL has a similar syntax to CCL.
The objective of CQL is different. Where CCL aims to be
an end-user language, CQL is <emphasis>the</emphasis> protocol
- query language for SRW.
+ query language for SRU.
</para>
<tip>
<para>
If you are new to CQL, read the
- <ulink url="http://zing.z3950.org/cql/intro.html">Gentle
- Introduction</ulink>.
+ <ulink url="&url.cql.intro;">Gentle Introduction</ulink>.
</para>
</tip>
<para>
<listitem>
<para>
The parser converts a valid CQL query to PQF, thus providing a
- way to use CQL for both SRW/SRU servers and Z39.50 targets at the
+ way to use CQL for both SRU servers and Z39.50 targets at the
same time.
</para>
</listitem>
<listitem>
<para>
The parser converts CQL to
- <ulink url="http://www.loc.gov/z3950/agency/zing/cql/xcql.html">
- XCQL</ulink>.
+ <ulink url="&url.xcql;">XCQL</ulink>.
XCQL is an XML representation of CQL.
- XCQL is part of the SRW specification. However, since SRU
+ XCQL is part of the SRU specification. However, since SRU
supports CQL only, we don't expect XCQL to be widely used.
Furthermore, CQL has the advantage over XCQL that it is
easy to read.
</listitem>
</itemizedlist>
</para>
- <sect3 id="tools.cql.parsing"><title>CQL parsing</title>
+ <sect3 id="cql.parsing"><title>CQL parsing</title>
<para>
A CQL parser is represented by the <literal>CQL_parser</literal>
handle. Its contents should be considered &yaz; internal (private).
A CQL query is parsed by the <function>cql_parser_string</function>
which takes a query <parameter>str</parameter>.
If the query was valid (no syntax errors), then zero is returned;
- otherwise a non-zero error code is returned.
+ otherwise -1 is returned to indicate a syntax error.
</para>
<para>
<synopsis>
</para>
</sect3>
- <sect3 id="tools.cql.tree"><title>CQL tree</title>
+ <sect3 id="cql.tree"><title>CQL tree</title>
<para>
- The the query string is validl, the CQL parser
+ The the query string is valid, the CQL parser
generates a tree representing the structure of the
CQL query.
</para>
<synopsis>
#define CQL_NODE_ST 1
#define CQL_NODE_BOOL 2
-#define CQL_NODE_MOD 3
struct cql_node {
int which;
union {
struct {
char *index;
+ char *index_uri;
char *term;
char *relation;
+ char *relation_uri;
struct cql_node *modifiers;
- struct cql_node *prefixes;
} st;
struct {
char *value;
struct cql_node *left;
struct cql_node *right;
struct cql_node *modifiers;
- struct cql_node *prefixes;
- } bool;
- struct {
- char *name;
- char *value;
- struct cql_node *next;
- } mod;
+ } boolean;
} u;
};
</synopsis>
- There are three kinds of nodes, search term (ST), boolean (BOOL),
- and modifier (MOD).
+ There are two node types: search term (ST) and boolean (BOOL).
+ A modifier is treated as a search term too.
</para>
<para>
The search term node has five members:
</listitem>
<listitem>
<para>
+ <literal>index_uri</literal>: index URi for search term
+ or NULL if none could be resolved for the index.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
<literal>term</literal>: the search term itself.
</para>
</listitem>
</listitem>
<listitem>
<para>
- <literal>modifiers</literal>: relation modifiers for search
- term. The <literal>modifiers</literal> is a simple linked
- list (NULL for last entry). Each relation modifier node
- is of type <literal>MOD</literal>.
+ <literal>relation_uri</literal>: relation URI for search term.
</para>
</listitem>
<listitem>
<para>
- <literal>prefixes</literal>: index prefixes for search
- term. The <literal>prefixes</literal> is a simple linked
- list (NULL for last entry). Each prefix node
- is of type <literal>MOD</literal>.
+ <literal>modifiers</literal>: relation modifiers for search
+ term. The <literal>modifiers</literal> list itself of cql_nodes
+ each of type <literal>ST</literal>.
</para>
</listitem>
</itemizedlist>
<literal>modifiers</literal>: proximity arguments.
</para>
</listitem>
- <listitem>
- <para>
- <literal>prefixes</literal>: index prefixes.
- The <literal>prefixes</literal> is a simple linked
- list (NULL for last entry). Each prefix node
- is of type <literal>MOD</literal>.
- </para>
- </listitem>
- </itemizedlist>
- </para>
-
- <para>
- The modifier node is a "utility" node used for name-value pairs,
- such as prefixes, proximity arguements, etc.
- <itemizedlist>
- <listitem>
- <para>
- <literal>name</literal> name of mod node.
- </para>
- </listitem>
- <listitem>
- <para>
- <literal>value</literal> value of mod node.
- </para>
- </listitem>
- <listitem>
- <para>
- <literal>next</literal>: pointer to next node which is
- always a mod node (NULL for last entry).
- </para>
- </listitem>
</itemizedlist>
</para>
</sect3>
- <sect3 id="tools.cql.pqf"><title>CQL to PQF conversion</title>
+ <sect3 id="cql.to.pqf"><title>CQL to PQF conversion</title>
<para>
Conversion to PQF (and Z39.50 RPN) is tricky by the fact
that the resulting RPN depends on the Z39.50 target
capabilities (combinations of supported attributes).
- Furthermore, the CQL and SRW operates on index prefixes
+ In addition, the CQL and SRU operates on index prefixes
(URI or strings), whereas the RPN uses Object Identifiers
for attribute sets.
</para>
void cql_transform_close(cql_transform_t ct);
</synopsis>
The first two functions create a tranformation handle from
- either an already open FILE or from a filename.
+ either an already open FILE or from a filename respectively.
</para>
<para>
The handle is destroyed by <function>cql_transform_close</function>
</para>
<para>
If conversion failed, <function>cql_transform_buf</function>
- returns a non-zero error code; otherwise zero is returned
- (conversion successful).
+ returns a non-zero SRU error code; otherwise zero is returned
+ (conversion successful). The meanings of the numeric error
+ codes are listed in the SRU specifications at
+ <ulink url="&url.sru.diagnostics.list;"/>
+ </para>
+ <para>
+ If conversion fails, more information can be obtained by calling
+ <synopsis>
+int cql_transform_error(cql_transform_t ct, char **addinfop);
+ </synopsis>
+ This function returns the most recently returned numeric
+ error-code and sets the string-pointer at
+ <literal>*addinfop</literal> to point to a string containing
+ additional information about the error that occurred: for
+ example, if the error code is 15 (``Illegal or unsupported context
+ set''), the additional information is the name of the requested
+ context set that was not recognised.
+ </para>
+ <para>
+ The SRU error-codes may be translated into brief human-readable
+ error messages using
+ <synopsis>
+const char *cql_strerror(int code);
+ </synopsis>
</para>
<para>
If you wish to be able to produce a PQF result in a different
open <literal>FILE</literal>.
</para>
</sect3>
- <sect3 id="toolq.cql.xcql"><title>CQL to XCQL conversion</title>
+ <sect3 id="cql.to.rpn">
+ <title>Specification of CQL to RPN mappings</title>
+ <para>
+ The file supplied to functions
+ <function>cql_transform_open_FILE</function>,
+ <function>cql_transform_open_fname</function> follows
+ a structure found in many Unix utilities.
+ It consists of mapping specifications - one per line.
+ Lines starting with <literal>#</literal> are ignored (comments).
+ </para>
+ <para>
+ Each line is of the form
+ <literallayout>
+ <replaceable>CQL pattern</replaceable><literal> = </literal> <replaceable> RPN equivalent</replaceable>
+ </literallayout>
+ </para>
+ <para>
+ An RPN pattern is a simple attribute list. Each attribute pair
+ takes the form:
+ <literallayout>
+ [<replaceable>set</replaceable>] <replaceable>type</replaceable><literal>=</literal><replaceable>value</replaceable>
+ </literallayout>
+ The attribute <replaceable>set</replaceable> is optional.
+ The <replaceable>type</replaceable> is the attribute type,
+ <replaceable>value</replaceable> the attribute value.
+ </para>
+ <para>
+ The following CQL patterns are recognized:
+ <variablelist>
+ <varlistentry><term>
+ <literal>index.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
+ </term>
+ <listitem>
+ <para>
+ This pattern is invoked when a CQL index, such as
+ dc.title is converted. <replaceable>set</replaceable>
+ and <replaceable>name</replaceable> are the context set and index
+ name respectively.
+ Typically, the RPN specifies an equivalent use attribute.
+ </para>
+ <para>
+ For terms not bound by an index the pattern
+ <literal>index.cql.serverChoice</literal> is used.
+ Here, the prefix <literal>cql</literal> is defined as
+ <literal>http://www.loc.gov/zing/cql/cql-indexes/v1.0/</literal>.
+ If this pattern is not defined, the mapping will fail.
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry><term>
+ <literal>qualifier.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
+ (DEPRECATED)
+ </term>
+ <listitem>
+ <para>
+ For backwards compatibility, this is recognised as a synonym of
+ <literal>index.</literal><replaceable>set</replaceable><literal>.</literal><replaceable>name</replaceable>
+ </para>
+ </listitem>
+ </varlistentry>
+ <varlistentry><term>
+ <literal>relation.</literal><replaceable>relation</replaceable>
+ </term>
+ <listitem>
+ <para>
+ This pattern specifies how a CQL relation is mapped to RPN.
+ <replaceable>pattern</replaceable> is name of relation
+ operator. Since <literal>=</literal> is used as
+ separator between CQL pattern and RPN, CQL relations
+ including <literal>=</literal> cannot be
+ used directly. To avoid a conflict, the names
+ <literal>ge</literal>,
+ <literal>eq</literal>,
+ <literal>le</literal>,
+ must be used for CQL operators, greater-than-or-equal,
+ equal, less-than-or-equal respectively.
+ The RPN pattern is supposed to include a relation attribute.
+ </para>
+ <para>
+ For terms not bound by a relation, the pattern
+ <literal>relation.scr</literal> is used. If the pattern
+ is not defined, the mapping will fail.
+ </para>
+ <para>
+ The special pattern, <literal>relation.*</literal> is used
+ when no other relation pattern is matched.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry><term>
+ <literal>relationModifier.</literal><replaceable>mod</replaceable>
+ </term>
+ <listitem>
+ <para>
+ This pattern specifies how a CQL relation modifier is mapped to RPN.
+ The RPN pattern is usually a relation attribute.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry><term>
+ <literal>structure.</literal><replaceable>type</replaceable>
+ </term>
+ <listitem>
+ <para>
+ This pattern specifies how a CQL structure is mapped to RPN.
+ Note that this CQL pattern is somewhat to similar to
+ CQL pattern <literal>relation</literal>.
+ The <replaceable>type</replaceable> is a CQL relation.
+ </para>
+ <para>
+ The pattern, <literal>structure.*</literal> is used
+ when no other structure pattern is matched.
+ Usually, the RPN equivalent specifies a structure attribute.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry><term>
+ <literal>position.</literal><replaceable>type</replaceable>
+ </term>
+ <listitem>
+ <para>
+ This pattern specifies how the anchor (position) of
+ CQL is mapped to RPN.
+ The <replaceable>type</replaceable> is one
+ of <literal>first</literal>, <literal>any</literal>,
+ <literal>last</literal>, <literal>firstAndLast</literal>.
+ </para>
+ <para>
+ The pattern, <literal>position.*</literal> is used
+ when no other position pattern is matched.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry><term>
+ <literal>set.</literal><replaceable>prefix</replaceable>
+ </term>
+ <listitem>
+ <para>
+ This specification defines a CQL context set for a given prefix.
+ The value on the right hand side is the URI for the set -
+ <emphasis>not</emphasis> RPN. All prefixes used in
+ index patterns must be defined this way.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </para>
+ <example id="example.cql.to.rpn.mapping"><title>CQL to RPN mapping file</title>
+ <para>
+ This simple file defines two context sets, three indexes and three
+ relations, a position pattern and a default structure.
+ </para>
+ <programlisting><![CDATA[
+ set.cql = http://www.loc.gov/zing/cql/context-sets/cql/v1.1/
+ set.dc = http://www.loc.gov/zing/cql/dc-indexes/v1.0/
+
+ index.cql.serverChoice = 1=1016
+ index.dc.title = 1=4
+ index.dc.subject = 1=21
+
+ relation.< = 2=1
+ relation.eq = 2=3
+ relation.scr = 2=3
+
+ position.any = 3=3 6=1
+
+ structure.* = 4=1
+]]>
+ </programlisting>
+ <para>
+ With the mappings above, the CQL query
+ <screen>
+ computer
+ </screen>
+ is converted to the PQF:
+ <screen>
+ @attr 1=1016 @attr 2=3 @attr 4=1 @attr 3=3 @attr 6=1 "computer"
+ </screen>
+ by rules <literal>index.cql.serverChoice</literal>,
+ <literal>relation.scr</literal>, <literal>structure.*</literal>,
+ <literal>position.any</literal>.
+ </para>
+ <para>
+ CQL query
+ <screen>
+ computer^
+ </screen>
+ is rejected, since <literal>position.right</literal> is
+ undefined.
+ </para>
+ <para>
+ CQL query
+ <screen>
+ >my = "http://www.loc.gov/zing/cql/dc-indexes/v1.0/" my.title = x
+ </screen>
+ is converted to
+ <screen>
+ @attr 1=4 @attr 2=3 @attr 4=1 @attr 3=3 @attr 6=1 "x"
+ </screen>
+ </para>
+ </example>
+ <example id="example.cql.to.rpn.bathprofile">
+ <title>CQL to RPN using Bath Profile</title>
+ <para>
+ The file <filename>etc/pqf.properties</filename> has mappings from
+ the Bath Profile and Dublin Core to RPN.
+ If YAZ is installed as a package it's usually located
+ in <filename>/usr/share/yaz/etc</filename> and part of the
+ development package, such as <literal>libyaz-dev</literal>.
+ </para>
+ </example>
+ </sect3>
+ <sect3 id="cql.xcql"><title>CQL to XCQL conversion</title>
<para>
Conversion from CQL to XCQL is trivial and does not
require a mapping to be defined.
<screen>
PROTO_Z3950
- PROTO_SR
+ PROTO_GENERAL
</screen>
<para>
- If you don't care about talking to SR-based implementations (few
- exist, and they may become fewer still if and when the ISO SR and ANSI
- Z39.50 documents are merged into a single standard), you can ignore
- this field on incoming packages, and always set it to PROTO_Z3950
- for outgoing packages.
+ Use <literal>PROTO_Z3950</literal> for Z39.50 Object Identifers,
+ <literal>PROTO_GENERAL</literal> for other types (such as
+ those associated with ILL).
</para>
<para>
<para>
again, corresponding to the specific OIDs defined by the standard.
+ Refer to the
+ <ulink url="&url.z39.50.oids;">
+ Registry of Z39.50 Object Identifiers</ulink> for the
+ whole list.
</para>
<para>
</para>
<para>
+ Three utility functions are provided for translating OIDs'
+ symbolic names (e.g. <literal>Usmarc</literal> into OID structures
+ (int arrays) and strings containing the OID in dotted notation
+ (e.g. <literal>1.2.840.10003.9.5.1</literal>). They are:
+ </para>
+
+ <screen>
+ int *oid_name_to_oid(oid_class oclass, const char *name, int *oid);
+ char *oid_to_dotstring(const int *oid, char *oidbuf);
+ char *oid_name_to_dotstring(oid_class oclass, const char *name, char *oidbuf);
+ </screen>
+
+ <para>
+ <literal>oid_name_to_oid()</literal>
+ translates the specified symbolic <literal>name</literal>,
+ interpreted as being of class <literal>oclass</literal>. (The
+ class must be specified as many symbolic names exist within
+ multiple classes - for example, <literal>Zthes</literal> is the
+ symbolic name of an attribute set, a schema and a tag-set.) The
+ sequence of integers representing the OID is written into the
+ area <literal>oid</literal> provided by the caller; it is the
+ caller's responsibility to ensure that this area is large enough
+ to contain the translated OID. As a convenience, the address of
+ the buffer (i.e. the value of <literal>oid</literal>) is
+ returned.
+ </para>
+ <para>
+ <literal>oid_to_dotstring()</literal>
+ Translates the int-array <literal>oid</literal> into a dotted
+ string which is written into the area <literal>oidbuf</literal>
+ supplied by the caller; it is the caller's responsibility to
+ ensure that this area is large enough. The address of the buffer
+ is returned.
+ </para>
+ <para>
+ <literal>oid_name_to_dotstring()</literal>
+ combines the previous two functions to derive a dotted string
+ representing the OID specified by <literal>oclass</literal> and
+ <literal>name</literal>, writing it into the buffer passed as
+ <literal>oidbuf</literal> and returning its address.
+ </para>
+
+ <para>
Finally, the module provides the following utility functions, whose
meaning should be obvious:
</para>
release the associated memory again. For the structures describing the
Z39.50 PDUs and related structures, it is convenient to use the
memory-management system of the &odr; subsystem (see
- <link linkend="odr-use">Using ODR</link>). However, in some circumstances
+ <xref linkend="odr.use"/>). However, in some circumstances
where you might otherwise benefit from using a simple nibble memory
management system, it may be impractical to use
<function>odr_malloc()</function> and <function>odr_reset()</function>.
</para>
</sect1>
+
+ <sect1 id="tools.log"><title>Log</title>
+ <para>
+ &yaz; has evolved a fairly complex log system which should be useful both
+ for debugging &yaz; itself, debugging applications that use &yaz;, and for
+ production use of those applications.
+ </para>
+ <para>
+ The log functions are declared in header <filename>yaz/log.h</filename>
+ and implemented in <filename>src/log.c</filename>.
+ Due to name clash with syslog and some math utilities the logging
+ interface has been modified as of YAZ 2.0.29. The obsolete interface
+ is still available if in header file <filename>yaz/log.h</filename>.
+ The key points of the interface are:
+ </para>
+ <screen>
+ void yaz_log(int level, const char *fmt, ...)
+
+ void yaz_log_init(int level, const char *prefix, const char *name);
+ void yaz_log_init_file(const char *fname);
+ void yaz_log_init_level(int level);
+ void yaz_log_init_prefix(const char *prefix);
+ void yaz_log_time_format(const char *fmt);
+ void yaz_log_init_max_size(int mx);
+
+ int yaz_log_mask_str(const char *str);
+ int yaz_log_module_level(const char *name);
+ </screen>
+
+ <para>
+ The reason for the whole log module is the <function>yaz_log</function>
+ function. It takes a bitmask indicating the log levels, a
+ <literal>printf</literal>-like format string, and a variable number of
+ arguments to log.
+ </para>
+
+ <para>
+ The <literal>log level</literal> is a bit mask, that says on which level(s)
+ the log entry should be made, and optionally set some behaviour of the
+ logging. In the most simple cases, it can be one of <literal>YLOG_FATAL,
+ YLOG_DEBUG, YLOG_WARN, YLOG_LOG</literal>. Those can be combined with bits
+ that modify the way the log entry is written:<literal>YLOG_ERRNO,
+ YLOG_NOTIME, YLOG_FLUSH</literal>.
+ Most of the rest of the bits are deprecated, and should not be used. Use
+ the dynamic log levels instead.
+ </para>
+
+ <para>
+ Applications that use &yaz;, should not use the LOG_LOG for ordinary
+ messages, but should make use of the dynamic loglevel system. This consists
+ of two parts, defining the loglevel and checking it.
+ </para>
+
+ <para>
+ To define the log levels, the (main) program should pass a string to
+ <function>yaz_log_mask_str</function> to define which log levels are to be
+ logged. This string should be a comma-separated list of log level names,
+ and can contain both hard-coded names and dynamic ones. The log level
+ calculation starts with <literal>YLOG_DEFAULT_LEVEL</literal> and adds a bit
+ for each word it meets, unless the word starts with a '-', in which case it
+ clears the bit. If the string <literal>'none'</literal> is found,
+ all bits are cleared. Typically this string comes from the command-line,
+ often identified by <literal>-v</literal>. The
+ <function>yaz_log_mask_str</function> returns a log level that should be
+ passed to <function>yaz_log_init_level</function> for it to take effect.
+ </para>
+
+ <para>
+ Each module should check what log bits it should be used, by calling
+ <function>yaz_log_module_level</function> with a suitable name for the
+ module. The name is cleared from a preceding path and an extension, if any,
+ so it is quite possible to use <literal>__FILE__</literal> for it. If the
+ name has been passed to <function>yaz_log_mask_str</function>, the routine
+ returns a non-zero bitmask, which should then be used in consequent calls
+ to yaz_log. (It can also be tested, so as to avoid unnecessary calls to
+ yaz_log, in time-critical places, or when the log entry would take time
+ to construct.)
+ </para>
+
+ <para>
+ Yaz uses the following dynamic log levels:
+ <literal>server, session, request, requestdetail</literal> for the server
+ functionality.
+ <literal>zoom</literal> for the zoom client api.
+ <literal>ztest</literal> for the simple test server.
+ <literal>malloc, nmem, odr, eventl</literal> for internal debugging of yaz itself.
+ Of course, any program using yaz is welcome to define as many new ones, as
+ it needs.
+ </para>
+
+ <para>
+ By default the log is written to stderr, but this can be changed by a call
+ to <function>yaz_log_init_file</function> or
+ <function>yaz_log_init</function>. If the log is directed to a file, the
+ file size is checked at every write, and if it exceeds the limit given in
+ <function>yaz_log_init_max_size</function>, the log is rotated. The
+ rotation keeps one old version (with a <literal>.1</literal> appended to
+ the name). The size defaults to 1GB. Setting it to zero will disable the
+ rotation feature.
+ </para>
+
+ <screen>
+ A typical yaz-log looks like this
+ 13:23:14-23/11 yaz-ztest(1) [session] Starting session from tcp:127.0.0.1 (pid=30968)
+ 13:23:14-23/11 yaz-ztest(1) [request] Init from 'YAZ' (81) (ver 2.0.28) OK
+ 13:23:17-23/11 yaz-ztest(1) [request] Search Z: @attrset Bib-1 foo OK:7 hits
+ 13:23:22-23/11 yaz-ztest(1) [request] Present: [1] 2+2 OK 2 records returned
+ 13:24:13-23/11 yaz-ztest(1) [request] Close OK
+ </screen>
+
+ <para>
+ The log entries start with a time stamp. This can be omitted by setting the
+ <literal>YLOG_NOTIME</literal> bit in the loglevel. This way automatic tests
+ can be hoped to produce identical log files, that are easy to diff. The
+ format of the time stamp can be set with
+ <function>yaz_log_time_format</function>, which takes a format string just
+ like <function>strftime</function>.
+ </para>
+
+ <para>
+ Next in a log line comes the prefix, often the name of the program. For
+ yaz-based servers, it can also contain the session number. Then
+ comes one or more logbits in square brackets, depending on the logging
+ level set by <function>yaz_log_init_level</function> and the loglevel
+ passed to <function>yaz_log_init_level</function>. Finally comes the format
+ string and additional values passed to <function>yaz_log</function>
+ </para>
+
+ <para>
+ The log level <literal>YLOG_LOGLVL</literal>, enabled by the string
+ <literal>loglevel</literal>, will log all the log-level affecting
+ operations. This can come in handy if you need to know what other log
+ levels would be useful. Grep the logfile for <literal>[loglevel]</literal>.
+ </para>
+
+ <para>
+ The log system is almost independent of the rest of &yaz;, the only
+ important dependence is of <filename>nmem</filename>, and that only for
+ using the semaphore definition there.
+ </para>
+
+ <para>
+ The dynamic log levels and log rotation were introduced in &yaz; 2.0.28. At
+ the same time, the log bit names were changed from
+ <literal>LOG_something</literal> to <literal>YLOG_something</literal>,
+ to avoid collision with <filename>syslog.h</filename>.
+ </para>
+
+ </sect1>
+
+ <sect1 id="marc"><title>MARC</title>
+
+ <para>
+ YAZ provides a fast utility that decodes MARC records and
+ encodes to a varity of output formats. The MARC records must
+ be encoded in ISO2709.
+ </para>
+ <synopsis><![CDATA[
+ #include <yaz/marcdisp.h>
+
+ /* create handler */
+ yaz_marc_t yaz_marc_create(void);
+ /* destroy */
+ void yaz_marc_destroy(yaz_marc_t mt);
+
+ /* set XML mode YAZ_MARC_LINE, YAZ_MARC_SIMPLEXML, ... */
+ void yaz_marc_xml(yaz_marc_t mt, int xmlmode);
+ #define YAZ_MARC_LINE 0
+ #define YAZ_MARC_SIMPLEXML 1
+ #define YAZ_MARC_OAIMARC 2
+ #define YAZ_MARC_MARCXML 3
+ #define YAZ_MARC_ISO2709 4
+ #define YAZ_MARC_XCHANGE 5
+
+ /* supply iconv handle for character set conversion .. */
+ void yaz_marc_iconv(yaz_marc_t mt, yaz_iconv_t cd);
+
+ /* set debug level, 0=none, 1=more, 2=even more, .. */
+ void yaz_marc_debug(yaz_marc_t mt, int level);
+
+ /* decode MARC in buf of size bsize. Returns >0 on success; <=0 on failure.
+ On success, result in *result with size *rsize. */
+ int yaz_marc_decode_buf (yaz_marc_t mt, const char *buf, int bsize,
+ char **result, int *rsize);
+
+ /* decode MARC in buf of size bsize. Returns >0 on success; <=0 on failure.
+ On success, result in WRBUF */
+ int yaz_marc_decode_wrbuf (yaz_marc_t mt, const char *buf,
+ int bsize, WRBUF wrbuf);
+]]>
+ </synopsis>
+ <para>
+ A MARC conversion handle must be created by using
+ <function>yaz_marc_create</function> and destroyed
+ by calling <function>yaz_marc_destroy</function>.
+ </para>
+ <para>
+ All other function operate on a <literal>yaz_marc_t</literal> handle.
+ The output is specified by a call to <function>yaz_marc_xml</function>.
+ The <literal>xmlmode</literal> must be one of
+ <variablelist>
+ <varlistentry>
+ <term>YAZ_MARC_LINE</term>
+ <listitem>
+ <para>
+ A simple line-by-line format suitable for display but not
+ recommend for further (machine) processing.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>YAZ_MARC_MARCXML</term>
+ <listitem>
+ <para>
+ The resulting record is converted to MARCXML.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>YAZ_MARC_ISO2709</term>
+ <listitem>
+ <para>
+ The resulting record is converted to ISO2709 (MARC).
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </para>
+ <para>
+ The actual conversion functions are
+ <function>yaz_marc_decode_buf</function> and
+ <function>yaz_marc_decode_wrbuf</function> which decodes and encodes
+ a MARC record. The former function operates on simple buffers, the
+ stores the resulting record in a WRBUF handle (WRBUF is a simple string
+ type).
+ </para>
+ <example id="example.marc.display">
+ <title>Display of MARC record</title>
+ <para>
+ The followint program snippet illustrates how the MARC API may
+ be used to convert a MARC record to the line-by-line format:
+ <programlisting><![CDATA[
+ void print_marc(const char *marc_buf, int marc_buf_size)
+ {
+ char *result; /* for result buf */
+ int result_len; /* for size of result */
+ yaz_marc_t mt = yaz_marc_create();
+ yaz_marc_xml(mt, YAZ_MARC_LINE);
+ yaz_marc_decode_buf(mt, marc_buf, marc_buf_size,
+ &result, &result_len);
+ fwrite(result, result_len, 1, stdout);
+ yaz_marc_destroy(mt); /* note that result is now freed... */
+ }
+]]>
+ </programlisting>
+ </para>
+ </example>
+ </sect1>
+
</chapter>
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