module foo {
    yang-version 1;
    namespace "foo";
    prefix "foo";

    revision "2016-03-22" {
        description "test";
    }

    container root {
        leaf my-leaf {
            type my-type;
        }
    }

    typedef my-type {
        type union {
            type string {
                pattern "dp[0-9]+o[0-9]+";
            }
            type string {
                pattern "dp[0-9]+s[0-9]+(f[0-9]+)?(d[0-9]+)?";
            }
            type string {
                pattern "dp[0-9]+(P[0-9]+)?p[0-9]{1,3}s[0-9]{1,3}(f[0-9]+)?(d[0-9]+)?";
            }
            type string {
                pattern "dp[0-9]+p[0-9]+p[0-9]+";
            }
        }
    }
}