Comment PHP-specific advice. (Score 2, Insightful) 459
All in all good advice; I have some additional tips for PHP.
I think the number one issue for code re-use is avoiding name collisions. PHP doesn't support namespaces, so my approach has evolved to building classes, even for very procedural functionality. I have one library named after my (very unique) username that contains all the functionality that I find useful for my own projects. I usually repackage any functions I use from there in the case of outside projects that other people will be working on.
I also have to talk a little bit about PEAR. There are some really fantastic libraries there, but considering that it's supposed to be a peer-reviewed repository, it has a lot of crap too. Mostly in the form of stuff that's never made it out of beta, but also there are some libraries with untested functionality. Often this comes in the form of poorly conceived generalization of a problem. One of the things that makes an excellent programmer is the ability to decide how general a solution is ideal for a given situation. Always take third-party code with a grain of salt.
Finally, if you are serious about programming, take some time to learn the advanced features of other languages. PHP is an extremely utilitarian language, lots of built-in functionality, lots of free code available, but its a bit like a stone hammer--very crude. I would say almost every other language has more to offer in terms of expanding your programming mind: C, C++, Java, Perl, Ruby, Python, OCaml, etc. Understanding these languages will help you write better PHP. Also, don't be fooled by Javascript's seeming simplicity, it's actually a very powerful dynamic language with unique features worth studying.
I think the number one issue for code re-use is avoiding name collisions. PHP doesn't support namespaces, so my approach has evolved to building classes, even for very procedural functionality. I have one library named after my (very unique) username that contains all the functionality that I find useful for my own projects. I usually repackage any functions I use from there in the case of outside projects that other people will be working on.
I also have to talk a little bit about PEAR. There are some really fantastic libraries there, but considering that it's supposed to be a peer-reviewed repository, it has a lot of crap too. Mostly in the form of stuff that's never made it out of beta, but also there are some libraries with untested functionality. Often this comes in the form of poorly conceived generalization of a problem. One of the things that makes an excellent programmer is the ability to decide how general a solution is ideal for a given situation. Always take third-party code with a grain of salt.
Finally, if you are serious about programming, take some time to learn the advanced features of other languages. PHP is an extremely utilitarian language, lots of built-in functionality, lots of free code available, but its a bit like a stone hammer--very crude. I would say almost every other language has more to offer in terms of expanding your programming mind: C, C++, Java, Perl, Ruby, Python, OCaml, etc. Understanding these languages will help you write better PHP. Also, don't be fooled by Javascript's seeming simplicity, it's actually a very powerful dynamic language with unique features worth studying.
