I'm currently implementing a concatenative language, and have added OP's program as an example: https://github.com/pflanze/copycat/blob/master/examples/hp.scm h

I'm currently implementing a concatenative language, and have added OP's program as an example: https://github.com/pflanze/copycat/blob/master/examples/hp.scm https://github.com/pflanze/copycat/blob/master/examples/hp.s... This is closer to how the later HP models worked, where naming and quotations are available (via « »). (I happen to have had an HP-15C as well as my first calculator :)