hmscalcrpn is a calculator that performs its operations in hours, minutes and seconds instead of integers or floating point numbers. Calculator operation is based on Reverse Polish Notation instead of algebraic notation. The calculator uses a four-value long integer stack to store interim results. A seconds-only mode may be toggled on or off. . hmscalcrpn was written in object-oriented pascal, using the Free Pascal Compiler and the Lazarus IDE.
RPL/2 (Reverse Polish Lisp/2) is a langage derived from the RPL made by Hewlett-Packard for its HP-28S. It has some extensions (preprocessor, compilated libraries, new functions, parallel computing), a TeX output, and can draw graphics.