ying an
<span class=machine><span class=font-tt>int</span></span> argument (the value of the discriminating field),
and possibly another argument corresponding to the default field.
Examples:
</p><pre>
union u1 { case A: int x; case B: case C: double d; case D: ; }
         becomes type u1 = A of int | B of float | C of float | D
union u2 { case A: int x; case B: double d; default: ; }
         becomes type u2 = A of int | B of float | Default_u of int
union u3 { case A: int x; default: double d; }
        