In Emacs Calc I use <TAB> to swap the last two elements on the stack. The command for this is called calc-roll-down. What does "roll down" mean in this context?
When rolling the stack I would expect the whole stack rolls, but the default operation is just to swap the last two elements. (I know I can roll the stack with the same command (via C-u 0 <TAB>), but it is not the default operation of the command.)
Do I miss something here?
You can look at the implementation of calc-roll-down: it takes an argument n, but when called interactively with TAB that argument is nil. In that case, the function calls the subordinate function calc-roll-down-stack with an argument of 2, thereby exchanging the top two elements. But if you call it with a different argument n (e.g. C-u TAB would call it with a prefix argument of '(4) which the function interprets as 4), then the top n elements of the stack are indeed rolled.
