Tim Bray wrote a short piece on PHP and kicked up a huge hullabaloo in the land of weblogs. Here’s my contribution to the echolalia.

Tim writes that it’s his experience that systems written in PHP are all spaghetti. I don’t think that’s a coincidence, and there are two sides to that coin.

One side, which all the PHP apologists are citing with full justification, is that its nonchalant everything-but-the-kitchen-sink “standard” library approach and its wide deployment present such a low barrier to writing and re-/deploying code that a lot of people who only have small needs are empowered to meet them on their own, however messily. I have argued that this enabling function is a good thing and I stand steadfastly by that position.

But on the other side, well, PHP is… lousy. Just wretched. Why?

The language – and here I’m talking only about the core, that is, syntax, type system, object orientation support, scoping rules, and the like – is limited and haphazard: Haphazard, because it was never designed in any fashion: it grew out of a templating system with hodgepodge constructs for which orthogonality was only an afterthought. Limited, because while it’s all dynamically typed and garbage collected, it squanders most of that advantage by limiting itself to the expressive power of C, roughly. Anonymous functions are awkward to create, and I’m not sure closures are possible in any practical fashion at all. Lists are second-class citizens, always bound to arrays. Attempts to introspect end up looking comical. The standard code modularization mechanisms ( include , require ) are simple-minded textual inclusions.

This is my big complaint: all the API s are execrable . It starts with the built-in stuff: try to do something with the image functions or the zip file functions – I never figured out a way to avoid making my code look ugly. With the built-in library setting a bad example, it’s no surprise that the same issue extends to the packages available from the PEAR : awkward is the rule. In my opinion, that is what makes me and a lot of other people feel that PHP code resists being made clean. I feel the same way when I’m forced to use Tk in Perl: the API is so misshapen that you just can’t make your own code sitting on top of it look pretty.

The easy, obvious way to do things is often the incorrect one. There are lots of tutorials which will either not tell you to quote user input before interpolating it into SQL statements at all, or tell you to use addslashes for the purpose. In either case you are open to injection attacks – either gaping wide or just wide. What you really should do is use a function that respects the particular SQL dialect, such as mysql_escape_string … no wait, that’s dead code, I mean mysql_real_escape_string . Bleurgh. And once you’ve found out all that and understood it, properly quoting user input is still a pain in the bottocks and requires much more code than not bothering. Guess what casual coders will do? Now contrast Perl’s DBI , where using bind parameters is just as easy as not; and in fact, makes the code easier to read. How about working with strings in an encoding-aware fashion? That means nothing short of rolling your own string munging, with “help” from some typically byzantine API s – what fun! Which novice is going to know that they should? Who is going to bother? How many of them will get it right?

All of these flaws are interconnected; the morass is simply the result of the language being a templating system that grew too big for its breeches. I don’t believe the problems can be corrected in any sensible fashion; PHP will always be a templating system, however much it may be straining against its clothes.

And let me tell you, it’s still a great templating system! If all you need is to write a web app that consists of two pages, running four queries over a five-table database, there is nothing that will get you up and running faster.

But that doesn’t make it suitable for large-scale systems. It’s not that the premise does not scale, it’s just that this particular implementation of the premise does not. Apologists will sometimes argue that the flaws are a necessary evil in achieving the low barrier to entry; worse-is-better style. I don’t buy that argument for a second. There is no reason that a language could not be designed to address the precise problem space that PHP aims at, but be created from scratch to be big enough for its britches, without the slipshod, organic growth. There is no reason it would have to be any harder to get things done with a standard library that encourages good practices as the obvious and easy way to accomplish things.