procedure main(a)

    local i, cl, n, name_tbl

    cl := integer(getenv("CONTENT_LENGTH"))
    name_tbl := table()

    #
    # output a minimal header, terminated by two newlines
    #
    write("Content-type: text/html\x0A\x0A")

    #
    # check that the request is correctly formatted; output
    # error message if it's not
    #
    getenv("REQUEST_METHOD") == "POST" | {
        writes("<P>error:  METHOD must = \"POST\"</P>")
        exit(1)
    }
    getenv("CONTENT_TYPE") == "application/x-www-form-urlencoded" | {
        writes("<P>error:  this script is for decoding form results only</P>")
        exit(1)
    }

    #
    # enter name=value lines as key/value pairs in name_tbl
    #
    while line := makeline(&input, "&", cl) do {
	line := unescape_url(map(line), "+", " ")
	line ? {
	    n := tab(find("="))
	    move(1)
	    if not (/name_tbl[n] := tab(0)) then {
		writes("<P>error:  duplicate field name, ", n, "</P>")
		exit(1)
	    }
	}
    }