[%- USE money = format(l('$%.2f'));
    USE date;
    USE CGI = CGI_utf8;
    USE POSIX;
    SET DATE_FORMAT = l('%m/%d/%Y');

    # Don't wrap in l() here; do that where this format string is actually used.
    SET HUMAN_NAME_FORMAT = '[_1] [_2] [_3] [_4] [_5]';

    is_advanced = CGI.param("_adv").size;
    is_special = CGI.param("_special").size;

    # -----------------------------------------------------------------------------
    # mkurl( destination_page, params_to_set, params_to_clear )
    #
    # Current page, updated params:
    # mkurl('', {foo => 'bar', boo => 'baz'});
    #
    # New page, one param is a list:
    # mkurl('http://flarg.baz/squz', {foo => 'bar', boo => ['baz', 'faz']});
    #
    # New page, clear all existing params before applying new ones:
    # mkurl('/fuz/buster', {foo => 'bar', boo => 'baz'}, 1); 
    #
    # Current page, clear 'some_param' from the existing params:
    # mkurl('', {foo => 'bar', boo => 'baz'}, ['some_param']);
    MACRO mkurl(page, params, clear_params) BLOCK;

        # clone the query string to avoid clobberation
        cgi = CGI.new(CGI.query_string);

        # remove requested params
        IF clear_params.0; # array
            FOR p IN clear_params; cgi.delete(p); END;
        ELSIF clear_params;
            cgi.delete_all();
        END;

        # x and y are artifacts of using <input type="image" /> tags 
        # instead of true submit buttons, and their values are never used.
        cgi.delete('x', 'y'); 

        # apply user params
        FOR k IN params.keys;
            encoded = [];
            list = params.$k.0 ? params.$k : [params.$k];
            # CGI croaks on already-decoded strings.  force-encode to be safe.
            FOR p IN list; encoded.push(ctx.encode_utf8(p)); END;
            foo = cgi.param("-name", k, "-values", encoded);
        END;

        # for url brevity, remove any params that have no value
        FOR p IN cgi.param;
            val = cgi.param(p);
            IF val == ''; cgi.delete(p); END;
        END;

        IF page;
            IF cgi.query_string;
                page _ '?' _ cgi.query_string;
            ELSE;
                page;
            END;
        ELSE;
            # staying on the current page
            cgi.url("-path" => 1, "-query" => 1);
        END;
    END;
%]