提交 95f202c0 编写于 作者: T Tom Lane

Adjust description of use_strict parameter. Some other minor editorial

cleanup.
上级 f21e2622
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<chapter id="plperl">
......@@ -46,46 +46,18 @@ $PostgreSQL: pgsql/doc/src/sgml/plperl.sgml,v 2.43 2005/08/12 21:42:53 momjian E
<para>
To create a function in the PL/Perl language, use the standard
<xref linkend="sql-createfunction" endterm="sql-createfunction-title">
syntax. A PL/Perl function must always return a scalar value. You
can return more complex structures (arrays, records, and sets)
in the appropriate context by returning a reference.
Never return a list. Here follows an example of a PL/Perl
function.
syntax:
<programlisting>
CREATE FUNCTION <replaceable>funcname</replaceable> (<replaceable>argument-types</replaceable>) RETURNS <replaceable>return-type</replaceable> AS $$
# PL/Perl function body
$$ LANGUAGE plperl;
</programlisting>
The body of the function is ordinary Perl code.
The body of the function is ordinary Perl code. A PL/Perl function must
always return a scalar value. You can return more complex structures
(arrays, records, and sets) by returning a reference, as discussed below.
Never return a list.
</para>
<para>
As with ordinary Perl code, you should use the strict pragma,
which you can do in one of two ways:
<itemizedlist>
<listitem>
<para>
Globally, by adding <quote>plperl</quote> to the list of <xref
linkend="guc-custom-variable-classes"> and setting
<literal>plperl.use_strict</literal> to true in
<filename>postgresql.conf</filename>
</para>
</listitem>
<listitem>
<para>
One function at a time, by using PL/PerlU (you must be database
superuser to do this) and including
<programlisting>
use strict;
</programlisting>
in the function body.
</para>
</listitem>
</itemizedlist>
</para>
<para>
The syntax of the <command>CREATE FUNCTION</command> command requires
......@@ -205,13 +177,13 @@ SELECT * FROM perl_row();
<para>
PL/Perl functions can also return sets of either scalar or
composite types. In general, you'll want to return rows one at a
time both to speed up startup time and to keep from queueing up
composite types. Usually you'll want to return rows one at a
time, both to speed up startup time and to keep from queueing up
the entire result set in memory. You can do this with
<function>return_next</function> as illustrated below. Note that
after the last <function>return_next</function>, you must put
either <literal>return;</literal> or (better) <literal>return
undef;</literal>
either <literal>return</literal> or (better) <literal>return
undef</literal>.
<programlisting>
CREATE OR REPLACE FUNCTION perl_set_int(int)
......@@ -237,7 +209,7 @@ $$ LANGUAGE plperl;
contains either scalars, references to arrays, or references to
hashes for simple types, array types, and composite types,
respectively. Here are some simple examples of returning the entire
result set as a reference:
result set as an array reference:
<programlisting>
CREATE OR REPLACE FUNCTION perl_set_int(int) RETURNS SETOF INTEGER AS $$
......@@ -267,6 +239,27 @@ SELECT * FROM perl_set();
it is a hazard if you declare a <application>PL/Perl</> function
as returning a domain type.
</para>
<para>
If you wish to use the <literal>strict</> pragma with your code,
the easiest way to do so is to <command>SET</>
<literal>plperl.use_strict</literal> to true. This parameter affects
subsequent compilations of <application>PL/Perl</> functions, but not
functions already compiled in the current session. To set the
parameter before <application>PL/Perl</> has been loaded, it is
necessary to have added <quote><literal>plperl</></> to the <xref
linkend="guc-custom-variable-classes"> list in
<filename>postgresql.conf</filename>.
</para>
<para>
Another way to use the <literal>strict</> pragma is to just put
<programlisting>
use strict;
</programlisting>
in the function body. But this only works for <application>PL/PerlU</>
functions, since <literal>use</> is not a trusted operation.
</para>
</sect1>
<sect1 id="plperl-database">
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<chapter Id="runtime">
......@@ -4382,10 +4382,10 @@ dynamic_library_path = 'C:\tools\postgresql;H:\my_project\lib;$libdir'
when using custom variables:
<programlisting>
custom_variable_classes = 'plr,pljava'
custom_variable_classes = 'plr,plperl'
plr.path = '/usr/lib/R'
pljava.foo = 1
plruby.bar = true # generates error, unknown class name
plperl.use_strict = true
plruby.use_strict = true # generates error: unknown class name
</programlisting>
</para>
</sect2>
......
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