# Trivial double loop - build, then print
my $aref=[]; #reference to anonymous array.
foreach $thing (@thingies) {
   push @{$aref},foo($thing);
}

print_table($aref);
#...
sub print_table {
    my $aryref=shift
    foreach my $thing (@{$aryref}) {
    #etc.
    }
}

##</code><code>##

#bypass cgi's html facilities
print '<table>';
 foreach $thing (@thingies){
       #foo returns an array of cell contents.
       print '<tr><td>',join('</td><td>',
             foo($thing)),'</td><tr>'; 
}
print '</table>';