why prime has two modes? RPN and CAS?

[Joe Horn]

(05-03-2014 02:00 AM)lemontea Wrote:  I want to ask, can you program the RPN side?

FACT: Prime is programmable (HP PPL), and you can call your programs when you are in RPN mode, but HP PPL is variable oriented, not stack oriented, and there are no programmable stack commands in HP PPL. You can't even explode a list onto the stack. RPN mode is intended to be merely an "Entry Mode" for keyboard calculations for those who prefer it over algebraic syntax.

OPINION: If you want and/or need to program in RPN, the Prime is not for you. However, if you only need RPN for keyboard calculations (which is where RPN really shines), and can program the Prime in PPL (which is MUCH easier than programming in RPN!), then Prime MIGHT be a good match for you.