Are you sure you're not talking about a
REPL?
Read -
Evaluate -
Print -
Loop. You find those a lot in functional language implementations and I've heard that
Java 9 will have one too.
I've never seen the term RPEL before. Besides, it doesn't really make sense. What are you printing if you haven't evaluated yet?
If so, then I've commonly heard it pronounced "reh-ple" / "repple", which is what Bear said.