Metaphysics of Software Engineering

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Lecture 1

• Metaphysics of Software Engineering

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Beauty in Software Engineering

• A piece of code is beautiful if every line in
  it serves a concrete, explainable purpose.

3
Beauty in Software Engineering

• A design is beautiful if it creates all
  encompassing and succinct model of the process.

4
Occams Razor

• Things must be no more complicated than
  they really need to be.

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Patterns

• 1,0,1,1,0,1,1,1,0,....

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Simple self-referential sentence, which is
undecidable

• This sentence is false.

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Turing Theorem

• It is not possible to determine via
  mathematical algorithmic procedure whether given
  Turing machine will halt on the given input.
• Or simply There are things that are not
  possible to compute!

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Modeling

• What is it that will make our models better,
  closer to perceived reality?

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What is a Class?

• Class is a category, aggregate abstraction,
  a philosophical form, which unites underlies and
  describes objects or entities of similar type.
• That is (notice the recursion here), entities
  which are similar enough to be assigned to a
  single class. Class is a blueprint for an object.
  Class, as far as program is concerned, is a meta
  physical entity
• (well, maybe not in Java ).

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What is an Object?

• Object, is a member, instance of a class.
  Objects are grouped into classes by similar
  features. Object, as far as program is concerned,
  is a physical entity.

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Example

• public class Human
• // Constructs human with first name, last
  name date of birth
• public Human( String sFirstName, String
  sLastName )
• this.sFirstName sFirstName
• this.sLastName sLastName
• public String getFirstName() return
  sFirstName
• public String getLastName() return
  sLastName
• public String toString() return
  sFirstName " " sLastName
• private String sFirstName, sLastName
• // Lets try it out
• public static void main( String args )
• Human ka new Human("Ken", "Arnold")
• // an instance of a class is object
• System.out.println( "We have created
  human " ka.getName() "" )

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Please read

• The Construction of Human-Computer Interfaces
  Considered as a Craft,
• by David Wroblewski
• This article can be found under resources and as
  a link from lecture 1 page