Æliens

Abstraction -- programming methodology

• control abstractions -- structured programming
• data abstraction -- information hiding

The kind of abstraction provided by ADTs can be supported by any language with a procedure call mechanism (given that appropriate protocols are developed and observed by the programmer).  [DT88]

Abstract data types -- foundational perspective

• unambiguous values in some semantic domain

Mathematical models -- types as constraints

• algebra -- set oriented
• second order lambda calculus -- polymorphic types
• constructive mathematics -- formulas as types

Objectives of typed OOP -- system description

• packaging in a coherent manner
• flexible style of associating operations with objects
• inheritance of description components -- reuse, understanding
• separation of specification and implementation
• explicit typing to guide binding decisions