what is data abstraction?
data abstraction is a modularity mechanism in which
- a small set of procedures act on data values
- only these procedures manipulate the data directly
basic terms
- abstract data type
procedures and the values they manipulate
- client
the code that uses the data abstraction
- representation
how the values of the abstract data type are represented
(eg, as an integer, as a cons cell)
- constructor
a procedure that constructs values of the abstract type
- selector, observer
a procedure that takes values of the abstract type
and returns values of another type