I have been on a long hunt for a PHP framework so I was going to write up an article about PHP frameworks, but then I thought I should back up a bit and talk about what a framework is and why you should use one.
Software driven computing has existed for over 60 years. In the early days computer programming was performed using long series of numbers to represent the electronic switches tell a computer what to do—computers still work this way. Fortunately no one has to program computers by speaking computer-ese numbers anymore. With that kind of tedious programming, the most advanced programs would be tic-tac-toe games.
But numbers are the nuts-and-bolts of a computer’s operation. Designing a sky-scraper while having to dwell on every nut and bolt of its construction might limit us to working in ten story buildings. It is vitally important in designing complex systems to be able to think at more abstract, level. Programming using numbers quickly led to “assembly language” as mnemonic way of specifying those numbers, then to “third-generation” programming languages (such as C, C++, Pascal, Fortran) which allow programs to be written without regard to the numbers that the computers can actually interpret. This frees software designers to think about problem-solving without being encumbered by the tediousness of the numerical “nuts-and-bolts” needed by the computers that run the programs.
Constructing a building does not occur in isolation; its context involves the skills and machinery of those involved as well as governmental and environmental infrastructure. Over the past 30+ years, the complexity of computing has given rise to very advanced operating systems that define the context in which a program runs. Add to that, the interactions between a program and other programs or data that exist across a network or even the internet and the complexity of issues add to the tediousness of dealing with nuts and bolts. Again, if a software designer has to dwell on the minutia of all these elements, modern complex, powerful software would never be completed.
A framework attempts to encapsulate the complexities of designing and implementing software. A good framework allows software design to occur more abstractly, unencumbered by the tediousness of the contextual details of the environment. Said a different way, a good framework allows the software designers to focus on the application’s purpose rather than the complexities of implementation.
Software is constructed in layers or components. Encapsulation is one of my favorite concepts in software design and implementation. It embodies the idea that there are specifics at every level or component within the software system that need not be exposed outside that implementation for that level. There are two key side-effects of this: (1) it prevents parts of the program outside the component from messing with or depending on implementation details which leads to (2) each component’s implementation can be changed or improved without fear of adversely affecting use of the component in unexpected ways. This leads to more stable, maintainable products.
Good programmers embed encapsulation within their design and implementation. Many object-oriented programming languages attempt to formalize this concept so that it is easy to do this. Well designed frameworks do the same, “protecting” some parts of the program from complex or variable implementation details.
There are good frameworks and there are bad ones. In a later article, I will discuss some of the issues to consider in picking a framework.
What have been your experiences in using programming frameworks?