50g multiple output

[John Keith]

(12-05-2021 06:23 PM)oierpa Wrote:  Can you suggest me some readings, article, manual or website that explain a little more how variables are used inside program?

One very good source is https://literature.hpcalc.org/. Nearly every HP manual is available there, as well as many third party manuals. Even better is the Museum thumb drive which has even more manuals and literature in a convenient form.

Specifically, the Programming section in the HP 50g advanced user's reference has the info you are looking for. The 50g users manual is somewhat infuriating to use because every example has both RPN and algebraic versions. The HP48G user's manual is more readable but obviously doesn't cover features of newer calculators. William Wickes' HP48 Insights (GX Version) is also a valuable reference. It is on the thumb drive but not on hpcalc.org.

RPL is an unusual programming language, especially compared to BASIC which is used on many other scientific calculators. Some people love it, others hate it or just never get it. RPL is based primarily on LISP and FORTH so familiarity with those languages is helpful. The local variable structure that you are having trouble with is similar to lambda expressions as you would find in LISP, Python or Haskell.