What if we changed the Daffodil CLI to have a --server mode.
In this mode the CLI would reads command-lines from std input, then does what it does now for a command line, but at the end it would go back to reading another command from std input, and stay in that loop until EOF on std input. This would let people build quite efficient shell scripts that avoid most Daffodil startup overheads and would be reasonably efficient even for quite small input data items. I suppose we'd want this to recognize that a schema is already loaded or already compiled so as to avoid that overhead on repeated uses of that schema/binary. Other than that this seems simple and useful. Thoughts?
