URI builder API

An API to assist with building valid URI strings (including URI escaping) would be very useful. Something along the lines of:

    string build_uri(string base, list<string> endpoint, map<string, string> parameters);

so I can do:

    string uri = build_uri("http://mydomain.com", { "specify", "my", "endpoint" }, { { "param1", "hello there" }, { "param2", "banana" } });

which should result in the URI:

    http://mydomain.com/specify/my/endpoint?param1=hello%20there&param2=banana