Send Close Add comments: (status displays here)
Got it!  This site "creationpie.com" uses cookies. You consent to this by clicking on "Got it!" or by continuing to use this website.  Note: This appears on each machine/browser from which this site is accessed.
Classes and objects
by RS  admin@creationpie.com : 1024 x 640


1. Classes and objects

2. Smalltalk
Byte Magazine Book: Smalltalk-80

Alan Kay wanted to make a computer so easy to use, a child could use it. Then maybe adults could use a computer. Steve Jobs saw what Alan Kay was doing and hired him away from Xerox to create the Apple MacIntosh computer, introduced in 1984.

Alan Kay (American computer scientist) was the originator of object-oriented, having developed the Smalltalk system in 1971, since "Children should program in smalltalk". I invented the term Object-Oriented, and I can tell you I did not have C++ in mind. Alan Kay (American computer scientist)

Information sign More: Alan Kay
Book: Smalltalk-80Smalltalk is an object-oriented language developed by Alan Kay (and others) at Xerox PARC in the 1970s.

Alan Kay wanted to make a computer so easy to use, a child could use it. Then maybe adults could use a computer. Steve Jobs saw what Alan Kay was doing and hired him away from Xerox to create the MacIntosh computer, introduced in 1984.

3. Classes and objects
UML class nodeAn understanding of classes and objects is essential to understanding object-oriented concepts.
 
What is an instance?
What is an object?
What is a class?



4. Cars and cookies


5. House analogy

6. Classes and objects
A cookie-cutter template is used to create a "cookie object" as an instance of an idea of a cookie - a "cookie class".
The Platonic idea of an "empty" class (cookie-cutter) needs to be filled in or "formed" (cookie dough) in order to create an Aristotelian object (cookie to be baked) for a "purpose" or end.

In animated movies, when one sees many similar animals, such as zebras in the movie Madagascar, one of which is "Marty", each zebra is an object created from a general zebra class (as a cookie-cutter template).


7. Reputation
Verse routePhilippians 2:7 But made himself of no reputation, and took upon him the form of a servant, and was made in the likeness of men: [kjv]
Verse routeαλλα εαυτον εκενωσεν μορφην δουλου λαβων εν ομοιωματι ανθρωπων γενομενος και σχηματι ευρεθεις ως ανθρωπος [gnt]
Verse routeformamfactusinventus … [v]

The Greek for "no reputation" is that of "empty form". An "empty form" is like a "hole" as a typed placeholder to be "informed" with something.

Keyhole Donut and hole Puzzle missing piece

The words "form" and "likeness" bring to mind the idea of Platonic forms and Aristotelian reality as found today in the class and object ideas of computer science.

The English word "form" is, through French, from the Latin word "forme""form, shape, appearance" which appears to be from the ancient Greek word "μορφή""shape, fashion, appearance".

Information sign More: Philippians 2:5-8 form of God and Aristotelian causes

8. Object properties, methods and events
An object has specific properties, methods, and reacts to or creates events. Some methods work better than other methods at accomplishing a given task. An event is triggered when something special happens.

 
What is a property of a class?
What is a method of a class?
What is an event of a class?



9. Mouse events
The desktop has properties: screen appearance In most GUI (Graphical User Interface) architectures, when the mouse moves on the screen, an event is created whenever it enters or leaves a control object such as a link object, a image object, etc. The object receives the message that the mouse is entering, and may change the appearance property of the mouse cursor. Likewise, when the mouse leaves a control object, the object receives a message and can change the cursor back to what it was.

10. The baby class and object
A baby can create events such as the cry event, the poop event, the hunger event, etc. These events require handling from an outside source.

11. Classes and objects
UML classes and objects Object C extends B

An understanding of classes and objects is essential to understanding object-oriented concepts.

12. End of page

by RS  admin@creationpie.com : 1024 x 640