I'm a big fan of my HP-28 calc and it's RPL. The programming language might seem odd, but on a device with (soft) keys that map to commands it makes sense. I w

I'm a big fan of my HP-28 calc and it's RPL. The programming language might seem odd, but on a device with (soft) keys that map to commands it makes sense. I was thinking about building my own physical calculator (i don't like to use smart phones for that, there is not nearly enough space for keys, and the keys give not appropriate feedback). I was looking for languages to use and I didn't find anything suitable. Forth was too raw. I didn't like factor, it seem unsuitable for a calculator. OpenRPL was, i don't know why, odd. This language, once it add other number types, and allow to omit the map, APL style, looks very promising. But writing a whole calculator software, with the menus and integrating the programming language, ability to plot functions, inspect variables and so on, was not a weekend project as first thought because the language has to be integrated deeply.