
'isempty : int X Array( int, dim) -> Boolean
'isempty( index, v) = ( index == 0 )

'isfull : int X Array( int, dim) -> Boolean
'isfull( index, v) = ( index >= dim )

'push : int X Array( int, dim) X int -> int X Array( int, dim)
'push( index, v, x) = ( index + 1, e( index, x, v))

'pop : int X Array( int, dim) -> int X Array( int, dim) X int
'pop( index, v) = ( index - 1, v, v[index - 1])


