Skins: A whole new look on everything :: Peter Dykstra Technology Essays

Skins: A whole new look on everything Concept Background: Dykstra's concepts of linear programming and modularity take on a whole new look. Peter Dykstra the father of linear programming suggested that anything that could be done in programming could be done with a combination of three basic procedures. Sequence- procedures performed in a linear order Decision- Expressions evaluated to determine between two routes of action. Repetition- The ability of a machine to perform an operation millions of times a second. In order to clean up the commonly used "spaghetti code" of the times, Dykestra then proceeded to say that all code should be divided up into "chunks" related to a specific tasks called modules. The idea was that by abstracting these modules into "black boxes" that with well-defined input they would perform their tasks and generate predictable output. This would allow a programmer to not know anything about the modules he was using except what goes in and what comes out and still be able to use it. This modular thinking was eventually applied to a GUI interface, but is still not widely utilized. What is a "skin"? The term "skin" was first coined by a MP3 player called xxx-AMP. The GUI interface of a program is modulated and broken out from the program as explained in the previous paragraph and given the ability to be swapped with other skins to change the entire appearance of the program. Would you ever guess them to be the exact same program? Would you ever guess the creators of these GUI interfaces were not paid to do it, or necessarily even professionals? My first introduction to a program that had some characteristics of skin like behavior was a shopping cart program with a â€Å"Look and Feel Module† that they had made public to great success. Groups of users would congregate around their site and support each other by swapping self generated custom modules and knowledge on how to create them. However it was far from easy and involved more Perl than HTML or graphics work. How Does it work? Skins in the HTML world follow the same concept. A skin is a simple HTML page with special hooks for the CGI (or ASP, etc.) to connect to. For example: in the HTML a variable that must be replaced with output from the CGI would be named '$$varname:' This will cause the tag to be replaced with the CGI Perl variable $varname.