How to use dfdl:discriminator with an array?

[Costello, Roger L.]

Hello DFDL community,

Yesterday Mike said this:


  *   A dfdl:discriminator says if something is true, then ... optional/array 
uncertainty is closed off, and no longer uncertain.
  *   I avoid using discriminators because I find ... for optional/array 
elements using dfdl:occursCountKind="expression" are superior.

Would you provide an example of using dfdl:discriminator with an 
optional/array, please?

/Roger