(RPL) percentage function % not preserving stack level 2

[rprosperi]

(01-05-2019 12:18 AM)cdmackay Wrote:  Having recently discovered the joys of percentage functions: % and Δ%/%CH on 15C
& 42S (and WP 34S), after years of doing them manually on other calculators or in my head, I
went looking for them on my 50g.

I'm surprised to find that, there, they don't preserve level 2 of the stack in
the way that on earlier calculators they preserved Y, which can be quite useful.

As others have noted, RPL tends to be more 'stack pure' while RPN did a lot of 'convenient', though non-standard, things which IMHO really did make them more useful. Returning dual results for % is the exact example I cite most when discussing this.

Note that %T is also very useful, though often not included in non-financial machines (but it is included in the 50g). The best way to do that in RPN is [1/X] [%] [1/X] as it is fast, and preserves the complete stack.

(01-05-2019 12:18 AM)cdmackay Wrote:  Of course, it's nothing that can't be done manually, or I could assign
≪ SWAP DUP ROT % ≫ to a key/menu (or something more clever, once I work it out).

If that's the right order you want, OVER SWAP is faster. Took me a long time while learning stackrobatics to appreciate and think of using OVER; it helps more often than you might think.