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Models and Programs

  • Článek

What's the word "Model" useful for?  People use it for all sorts of stuff, usually as distinct from "Program". Here's some definitions, ending up with the one I like best.

Model = pictures   (my score: 4/10)

  • UML is 'modeling' because it's mostly pictures
  • OCL (the constraint part of UML) isn't modeling, because it's text
    • The same goes for ancient specification languages like VDM and Z
  • C# isn't models, because it's text

Model = imprecise  (my score: 1/10)

  • Sketches in UML, pseudocode, text descriptions are models
  • Executable UML isn't models

Model = a processable description (my score: 7/10)

  • UML is models because it's more exact than natural language
  • Programs is models because they're exact enough for computers to execute
  • Sketchy drawings and descriptive waffle aren't models

Model = abstract (i.e., incomplete in relation to some useful criterion) (my score: 8/10)

  • UML is usually models because it's not complete enough to execute
  • C# is usually not models because if it's grammatically correct, then it can be executed
  • Test code is in a sense abstract because, in relation to the thing you're testing, the tests tell you some of what it's supposed to do, without actually being the implementation; so the tests are an abstract model of the item under test
  • An isolated aspect, partial class, or an abstract class or an interface is a model, because it tells you a bit about things that conform to them
  • Scientific and mathematical models are processable abstract descriptions.

Model = a set of statements in any language that you can infer things from (my score: 9/10)

  • UML aspires to be models because the idea is, you can deduce things from the diagrams
  • Programs is models because they have a clear meaning (set by the compiler)
  • Testsuites are models of the things they're testing

Model = an underlying set of relations of which you see abstract views (my score: 9/10 - and if combined with the previous, 10/10)

[thanks to Fred Thwaite for prompting me to add this]

  • Serious UML editors have multiple views that are all related together
  • Programs -- well, maybe especially if aspect-oriented ...