Stack: $[]-> []

pushTo:     function [st val]-> 'st ++ val
popStack:   function [st]     [
    result: last st
    remove 'st .index (size st)-1
    return result
]
emptyStack: function [st]-> empty 'st
printStack: function [st]-> print st

st: new Stack

pushTo st "one"
pushTo st "two"
pushTo st "three"
printStack st

print popStack st
printStack st

emptyStack st
print ["finally:" st]