Can we have RPN back?

[Joe Horn]

(01-27-2014 06:32 AM)Thomas Radtke Wrote:  

(01-27-2014 03:58 AM)Joe Horn Wrote:  [...]also accumulates each operation into an algebraic expression and shows that too.

Nice idea. If I'm not missing something, there's one inconvenience: The calculator will never know when an expression is 'finished'. You'd either have to clear the accumulator by hand or have a stack of expressions, which grows faster than the RPN stack.

Yes, running out of memory due to huge expressions or too many expressions is a very real consideration. However, a similar problem exists with ordinary infinite stack RPN. Such a stack (e.g. on the HP 50g) could conceivably grow and grow as calculation results are dumped onto the stack and abandoned there, until the machine starts to run out of memory and slow to a crawl. But when using it as a calculator, people don't do that; they instinctively clear the stack before each new set of problems. Those who don't clear it, quickly learn that they should, because a slow machine is annoying.

Therefore, one solution to the problem you mention is to just allow expressions to be as big as users need, knowing that they will keep them limited to real-world reasonable sizes, and clear them out between sets of problems. If they don't tidy up, Prime would bog down as it runs low on memory, just like real computers do. No need for artificial limits on stack size (although Prime already has that, unfortunately), or on expression size. The annoyance factor will cause users to work within reasonable limits.

Any ideas for other solutions?