enum variant

gistfile1

 ...
    fn visit_enter_enum_variant(_variant: uint,
                                _disr_val: int,
                                _n_fields: uint,
                                _name: &str) -> bool {
        do self.get::<int>() |e| {
            if e == _disr_val {
                self.out += _name;
            }
        };
        
        true
 
    }
    fn visit_enum_variant_field(_i: uint, inner: *tydesc) -> bool {
        self.visit_inner(inner)
    }
    fn visit_leave_enum_variant(_variant: uint,
                                _disr_val: int,
                                _n_fields: uint,
                                _name: &str) -> bool { true }

...

fn get_tydesc_for<T>(&&_t: T) -> *tydesc {
    get_tydesc::<T>()
}
pure fn conv_poly<T>(v: T) -> ~str {
    let p = ptr::addr_of(v) as *c_void;
    let u = fmt_visitor(@{mut ptr: p, mut out: ~""});
    unsafe { 
        let td = get_tydesc_for(v);
        visit_tydesc(td, u as ty_visitor); 
    }
    return copy u.out;
}
...

    #[test]
    fn enum_variant_type() {
        enum a {b, c};
        assert conv_poly(b) == ~"b";
        enum d {e(int), f(~str)};
        // FIXME: segfault
        assert conv_poly(e(10)) == ~"e(10)";
    }