FOREACH function implements a for loop on a list or map.
For each iteration i on a list, the i-th element on the list is put on top of the stack, and the exec macro is then called.
For each iteration i on a map, the exec macro is called with the i-th value on top of the stack, and the i-th key just below on the stack.
You can start your macro with
'value' STORE 'key' STORE.