Orpie is a fullscreen RPN calculator for the console.  Its operation is similar
to that of modern HP calculators, but data entry has been optimized for
efficiency on a PC keyboard.  Features include extensive scientific calculator
functionality, command completion, and a visible interactive stack.

Orpie is the successor of math/rpc by the same author; it has been completely
rewritten in Ocaml, and offers a number of features that were not available in
the older program.

WWW: http://www.eecs.umich.edu/~pelzlpj/orpie/