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Doc: improve documentation for ^@ starts-with operator.

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This operator wasn't formally documented anywhere.  To give it
a natural home, relabel the functions-string-other table as
"Other String Functions and Operators", which is more parallel
to the functions-string-sql table anyway.

While here, add cross-references to the pattern match and text
search sections.  It seems moderately likely that people would
come to this section looking for those (but I don't want to
actually list them in these tables).

Discussion: https://postgr.es/m/CADT4RqB13KQHOJqqQ+WXmYtJrukS2UiFdtfTvT-XA3qYLyB6Cw@mail.gmail.com
This commit is contained in:
Tom Lane 2021-10-09 14:42:52 -04:00
parent 8b76f89c37
commit 2ae5d72f00
1 changed files with 33 additions and 8 deletions
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41
doc/src/sgml/func.sgml
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@ -2708,18 +2708,23 @@ repeat('Pg', 4) <returnvalue>PgPgPgPg</returnvalue>
</table> </table>
<para> <para>
Additional string manipulation functions are available and are Additional string manipulation functions and operators are available
listed in <xref linkend="functions-string-other"/>. Some of them are used internally to implement the and are listed in <xref linkend="functions-string-other"/>. (Some of
<acronym>SQL</acronym>-standard string functions listed in <xref linkend="functions-string-sql"/>. these are used internally to implement
the <acronym>SQL</acronym>-standard string functions listed in
<xref linkend="functions-string-sql"/>.)
There are also pattern-matching operators, which are described in
<xref linkend="functions-matching"/>, and operators for full-text
search, which are described in <xref linkend="textsearch"/>.
</para> </para>
<table id="functions-string-other"> <table id="functions-string-other">
<title>Other String Functions</title> <title>Other String Functions and Operators</title>
<tgroup cols="1"> <tgroup cols="1">
<thead> <thead>
<row> <row>
<entry role="func_table_entry"><para role="func_signature"> <entry role="func_table_entry"><para role="func_signature">
Function Function/Operator
</para> </para>
<para> <para>
Description Description
@ -2731,6 +2736,25 @@ repeat('Pg', 4) <returnvalue>PgPgPgPg</returnvalue>
</thead> </thead>
<tbody> <tbody>
<row>
<entry role="func_table_entry"><para role="func_signature">
<indexterm>
<primary>character string</primary>
<secondary>prefix test</secondary>
</indexterm>
<type>text</type> <literal>^@</literal> <type>text</type>
<returnvalue>boolean</returnvalue>
</para>
<para>
Returns true if the first string starts with the second string
(equivalent to the <function>starts_with()</function> function).
</para>
<para>
<literal>'alphabet' ^@ 'alph'</literal>
<returnvalue>t</returnvalue>
</para></entry>
</row>
<row> <row>
<entry role="func_table_entry"><para role="func_signature"> <entry role="func_table_entry"><para role="func_signature">
<indexterm> <indexterm>
@ -5285,9 +5309,10 @@ cast(-44 as bit(12)) <lineannotation>111111010100</lineannotation>
</para> </para>
<para> <para>
Also see the prefix operator <literal>^@</literal> and corresponding Also see the starts-with operator <literal>^@</literal> and the
<function>starts_with</function> function, which are useful in cases corresponding <function>starts_with()</function> function, which are
where simply matching the beginning of a string is needed. useful in cases where simply matching the beginning of a string is
needed.
</para> </para>
</sect2> </sect2>