The procedure erase simply removes one item from the stack, so in:
erase(2 + 2) =>the expression in the parentheses will be evaluated but no result will be printed. Erase is sometimes useful if you want only one of the results of a procedure which produces two results. E.g. the operation `//' performs integer division putting the remainder and the quotient on the stack:
23 // 6 =>
** 5 3
If you wanted to assign only the remainder to X, you could do:
erase(23 // 6) -> x;
x =>
** 5
or, using an extra "assignment to nothing" instead of erase:
(23 // 6) -> -> x;
x =>
** 5
(Actually the infix operation REM does the same:
23 rem 6 -> x;
x =>
** 5
)
To assign the divisor first assign the top of the stack, then erase the second result:
erase(23 // 6 -> x);
x =>
** 3
or, using assignment to nothing
23 // 6 -> x ->;
x =>
** 3
(This can be done instead using the infix operator `div':
23 div 6 =>
** 3
)