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<title>38.4.Global Values in PL/Perl</title>
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<a name="plperl-global"></a>38.4.Global Values in PL/Perl</h2></div></div></div>
<p> You can use the global hash <code class="varname">%_SHARED</code> to store
data, including code references, between function calls for the
lifetime of the current session.
</p>
<p> Here is a simple example for shared data:
</p>
<pre class="programlisting">CREATE OR REPLACE FUNCTION set_var(name text, val text) RETURNS text AS $$
if ($_SHARED{$_[0]} = $_[1]) {
return 'ok';
} else {
return "can't set shared variable $_[0] to $_[1]";
}
$$ LANGUAGE plperl;
CREATE OR REPLACE FUNCTION get_var(name text) RETURNS text AS $$
return $_SHARED{$_[0]};
$$ LANGUAGE plperl;
SELECT set_var('sample', 'Hello, PL/Perl! How's tricks?');
SELECT get_var('sample');</pre>
<p>
</p>
<p> Here is a slightly more complicated example using a code reference:
</p>
<pre class="programlisting">CREATE OR REPLACE FUNCTION myfuncs() RETURNS void AS $$
$_SHARED{myquote} = sub {
my $arg = shift;
$arg =~ s/(['\\])/\\$1/g;
return "'$arg'";
};
$$ LANGUAGE plperl;
SELECT myfuncs(); /* initializes the function */
/* Set up a function that uses the quote function */
CREATE OR REPLACE FUNCTION use_quote(TEXT) RETURNS text AS $$
my $text_to_quote = shift;
my $qfunc = $_SHARED{myquote};
return &$qfunc($text_to_quote);
$$ LANGUAGE plperl;</pre>
<p>
(You could have replaced the above with the one-liner
<code class="literal">return $_SHARED{myquote}->($_[0]);</code>
at the expense of readability.)
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