I also use clac on my desktop (https://github.com/soveran/clac https://github.com/soveran/clac). It's a line-oriented RPN calculator like Unix dc, but it shows

I also use clac on my desktop (https://github.com/soveran/clac https://github.com/soveran/clac). It's a line-oriented RPN calculator like Unix dc, but it shows the stack dynamically as you type. I have a long-term ambition to port it to a physical calculator - either my own design or one like the Numworks or a SwissMicro (a recreation of the HP-42s).