What is a Theme?

Back in the mid 1970s, programming code became so immense that changing even the smallest part of a piece of code could have unpredictable effects in the other areas of the program. This led to the development of a concept called modular programming, which essentially broke the program down into smaller more manageable junks that were called upon by the main program when needed. The term for modular programming these days is separation of concerns or SoC. But no matter what you call it, this is its function.

In e107 a theme contains a set of modular code containing XHTML (eXtensible HyperText Markup Language) and CSS (Cascading Style Sheets). In its most basic explanation, XHTML allows us to take a text document, create a link to other documents, and the eXtensible part of the language allows you to create your own tags describing data. Thus a program like e107 can use these tags to extract the information it needs. The data shouldn’t show up on the screen like a computer...