You can use the global hash %_SHARED to store data, including code references, between function calls for the lifetime of the current session.
Here is a simple example for shared data:
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');
Here is a slightly more complicated example using a code reference:
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; (You could have replaced the above with the one-liner return $_SHARED{myquote}->($_[0]); at the expense of readability.)
