- <sect3 id="character-map-files">
- <title>The character map file format</title>
- <para>
- The contents of the character map files are structured as follows:
- </para>
-
- <para>
- <variablelist>
-
- <varlistentry>
- <term>lowercase <emphasis>value-set</emphasis></term>
- <listitem>
- <para>
- This directive introduces the basic value set of the field type.
- The format is an ordered list (without spaces) of the
- characters which may occur in "words" of the given type.
- The order of the entries in the list determines the
- sort order of the index. In addition to single characters, the
- following combinations are legal:
- </para>
-
- <para>
-
- <itemizedlist>
- <listitem>
- <para>
- Backslashes may be used to introduce three-digit octal, or
- two-digit hex representations of single characters
- (preceded by <literal>x</literal>).
- In addition, the combinations
- \\, \\r, \\n, \\t, \\s (space — remember that real
- space-characters may not occur in the value definition), and
- \\ are recognized, with their usual interpretation.
- </para>
- </listitem>
-
- <listitem>
- <para>
- Curly braces {} may be used to enclose ranges of single
- characters (possibly using the escape convention described in the
- preceding point), eg. {a-z} to introduce the
- standard range of ASCII characters.
- Note that the interpretation of such a range depends on
- the concrete representation in your local, physical character set.
- </para>
- </listitem>
-
- <listitem>
- <para>
- paranthesises () may be used to enclose multi-byte characters -
- eg. diacritics or special national combinations (eg. Spanish
- "ll"). When found in the input stream (or a search term),
- these characters are viewed and sorted as a single character, with a
- sorting value depending on the position of the group in the value
- statement.
- </para>
- </listitem>
-
- </itemizedlist>
-
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>uppercase <emphasis>value-set</emphasis></term>
- <listitem>
- <para>
- This directive introduces the
- upper-case equivalencis to the value set (if any). The number and
- order of the entries in the list should be the same as in the
- <literal>lowercase</literal> directive.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>space <emphasis>value-set</emphasis></term>
- <listitem>
- <para>
- This directive introduces the character
- which separate words in the input stream. Depending on the
- completeness mode of the field in question, these characters either
- terminate an index entry, or delimit individual "words" in
- the input stream. The order of the elements is not significant —
- otherwise the representation is the same as for the
- <literal>uppercase</literal> and <literal>lowercase</literal>
- directives.
- </para>
- </listitem></varlistentry>
- <varlistentry>
- <term>map <emphasis>value-set</emphasis>
- <emphasis>target</emphasis></term>
- <listitem>
- <para>
- This directive introduces a mapping between each of the
- members of the value-set on the left to the character on the
- right. The character on the right must occur in the value
- set (the <literal>lowercase</literal> directive) of the
- character set, but it may be a paranthesis-enclosed
- multi-octet character. This directive may be used to map
- diacritics to their base characters, or to map HTML-style
- character-representations to their natural form, etc. The
- map directive can also be used to ignore leading articles in
- searching and/or sorting, and to perform other special
- transformations. See section <xref
- linkend="leading-articles"/>.
- </para>
- </listitem></varlistentry>
- </variablelist>
- </para>
- </sect3>
- <sect3 id="leading-articles">
- <title>Ignoring leading articles</title>
- <para>
- In addition to specifying sort orders, space (blank) handling,
- and upper/lowercase folding, you can also use the character map
- files to make Zebra ignore leading articles in sorting records,
- or when doing complete field searching.
- </para>
- <para>
- This is done using the <literal>map</literal> directive in the
- character map file. In a nutshell, what you do is map certain
- sequences of characters, when they occur <emphasis> in the
- beginning of a field</emphasis>, to a space. Assuming that the
- character "@" is defined as a space character in your file, you
- can do:
- <screen>
- map (^The\s) @
- map (^the\s) @
- </screen>
- The effect of these directives is to map either 'the' or 'The',
- followed by a space character, to a space. The hat ^ character
- denotes beginning-of-field only when complete-subfield indexing
- or sort indexing is taking place; otherwise, it is treated just
- as any other character.
- </para>
- <para>
- Because the <literal>default.idx</literal> file can be used to
- associate different character maps with different indexing types
- -- and you can create additional indexing types, should the need
- arise -- it is possible to specify that leading articles should
- be ignored either in sorting, in complete-field searching, or
- both.
- </para>
- <para>
- If you ignore certain prefixes in sorting, then these will be
- eliminated from the index, and sorting will take place as if
- they weren't there. However, if you set the system up to ignore
- certain prefixes in <emphasis>searching</emphasis>, then these
- are deleted both from the indexes and from query terms, when the
- client specifies complete-field searching. This has the effect
- that a search for 'the science journal' and 'science journal'
- would both produce the same results.
- </para>
- </sect3>
- </sect2>
- </sect1>
-
- <sect1 id="grs-exchange-formats">
- <title>GRS Exchange Formats</title>