#### Method: query_string
# Synthesize a query string from our current
# parameters
####
'query_string' => <<'END_OF_FUNC',
sub query_string {
    my($self) = self_or_default(@_);
    my($param,$value,@pairs);
    foreach $param ($self->param) {
        my($eparam) = escape($param);
        foreach $value ($self->param($param)) {
            $value = escape($value);
            push(@pairs,"$eparam=$value");
        }
    }
    return join($USE_PARAM_SEMICOLONS ? ';' : '&',@pairs);
}
[download]

- from CGI.pm

So it simply constructs a query string from the given name/value pairs already in the CGI object. It'll even use that far-out semicolon format if you want it to. :)