topical media & game development

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[] readme course(s) preface I 1 2 II 3 4 III 5 6 7 IV 8 9 10 V 11 12 afterthought(s) appendix reference(s) example(s) resource(s) _

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object-oriented programming

This chapter extended the notion of subtyping to include behavioral properties. In section 1, we discussed the interpretation of types as behavior and we looked at the issues involved in preserving invariance and history properties.

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Types as behavior

1

• subtype requirements -- preservation of behavioral properties
• behavioral properties -- invariance, history
• duality -- static versus dynamic constraints

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slide: Section 10.1: Types as behavior

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Also, we discussed the duality between static and dynamic type constraints. In section 2, a brief characterization of an assertion logic for verifying behavioral properties was given.

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Verifying behavioral properties

2

• states -- transformations
• verification -- correctness formulae
• axioms -- consequence rules, abstraction

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slide: Section 10.2: Verifying behavioral properties

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We looked at a formal characterization of states and state transitions and correctness formulae were introduced as a means to verify the correctness of transitions. We also looked at an axiomatic characterization of the correctness properties of programming language constructs.

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On the notion of behavior

3

• syntax -- expressions, statements
• rules -- assignment, object creation, method call
• compound rules -- composition, conditional, iteration

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slide: Section 10.3: On the notion of behavior

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In section 3, we looked at how the behavior of an object may be defined in a formal way by means of a transition system. A transition system for an object-based language specifies the rules for assignment, object creation and method call, as well as the computation steps resulting from the evaluation of compound statements.

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Objects as behavioral types

4

• abstract data types -- representation function
• correspondence -- abstraction, renaming, extension
• behavioral subtypes -- correspondence

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slide: Section 10.4: Objects as behavioral types

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In section 4, it was shown how actual objects may be related to abstract types by means of a representation abstraction function. Further, we discussed explicit guidelines for defining a subtype correspondence relation between behavioral types.

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Specifying behavioral compositions

5

• global invariants -- dynamic aliasing
• model-based specification -- state and operations
• compositions -- contracts, scripts, interaction, joint actions

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slide: Section 10.5: Specifying behavioral compositions

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Finally, in section 5, we looked at the problems involved in determining global invariants and we discussed what formal means we have available to specify behavioral properties of a collection of objects.

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[] readme course(s) preface I 1 2 II 3 4 III 5 6 7 IV 8 9 10 V 11 12 afterthought(s) appendix reference(s) example(s) resource(s) _

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(C) Æliens 04/09/2009

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