Program without using variables?

[DM48]

I am going down a few rabbit holes at the moment and I am exploring the idea of how to take numbers from the stack and use them in a program without storing them to a variable.

Yes, I know about local variables -> a b /<< a b + />> and I use them a lot.

The program I am writing now has six soft menu keys. 1 - 4 store a number from the stack into a variable. 5 executes the program. 6 cleans the variables from memory when I am done evaluating different numbers.

My first thought was to use a list. I place a list on the stack and when I press soft menu keys 1-4 it would store that number in the list on the stack in the appropriate order. This worked well, minus having to have the list on the stack.

Is there a different way to store variables without committing them to memory?