ENG key simulation

[salvomic]

hi,
I would like to thank the user cclinus for the original post, and now I'm posted in this thread a new version of the program to simulate the key ENG (←ENG and ENG→) that's on some calculator (also old HP, like HP 35 if I well remember).
The Prime should have such a key or at least simulate it. Our proposal (mine and cclinus') is to use key definition (User -> Shift-Help) of the keys ÷ X - + to get ENGB() and ENGA() (forward and afterward), prefix() (prefixes like m, µ, n, p, k, M, G...) and reeng() to restore the original float number.
Sometimes an user would like to momentarily switch in ENG mode and this "ENG simulator" could help.

Salvo