Tag Archives: PHP

Aspects of Love

Programming languages come and go at a frightening clip. Less often but still with some regularity, frameworks appear and disappear as well.

But it’s more infrequent that entire approaches to coding come along. Functional programming has been around forever. Object-oriented programming has been around nearly as long. But it’s only been a little more than a decade that the idea of <em>aspect-oriented programming</em>, or AOP, has been on the scene.

If you’re not familiar with AOP, some background might be helpful. A key idea behind AOP is that there are functions that your code needs to do which go across (or cross-cut) the entire application. In other paradigms, you then need to code bits of those functions all over the place. But in AOP, you do it only once.

One prototypical example is logging. If you’re writing an application that does anything significant, you probably write out to some kind of log when it happens. In a user-based application, for instance, you probably want to log every time you add a new user or delete a user.

Under other approaches, you need to call some kind of logging hook in your addUser and deleteUser functions (or methods). But with AOP, you can define a separate logging function, and tell it to attach to the deleteUser and addUser functions. The parts of the code that actually do the work with users aren’t touched at all.

Why is this helpful? Well, suppose you want to change how logging works or how you call the logging piece. You’d need to touch every place it’s called. With AOP, you just change the logging piece once, and you’re done.

Or suppose you decide well after the design stage that you want to add a layer of security to every user routine to make sure the person trying to make a change has permissions to do so. You could go find all of the functions and add calls to them, or you could just create a security-check routine and attach it to the relevant functions.

Compiled languages like Java and C++ have had this idea for a while now, but it has been slow to come to interpreted languages. With the Flow framework, for instance, PHP now has AOP capabilities. There’s still some roughness around the edges, but it’s a big step toward widespread adoption of this approach.

Watch this space…

The Rise And Fall Of Programming Languages

Everybody out there who is fluent in conversational Latin, please raise your hands. (Peering out) Not many. How about Esperanto? Perhaps a few more, although you all seem to have shaggy beards and a perpetually quizzical expression. (Not that there’s anything wrong with that.)

Human languages come and go, even though they are so closely identified with a people. There are efforts to keep them going wherever possible, and records indicate that there may be as many as a thousand or more so-called “endangered languages.”

So it should come as no surprise with the pace of technology that there are endangered programming languages as well. Some, like B, were stopgaps until something else came along. Others, like COBOL, were historically important but really aren’t around much today (other than a lingering small group).

When does a programming language become pervasive enough to get interested? And when does it wither enough in ubiquity that it’s no longer relevant for a project? Both are tough (and squishy) issues.

In terms of the upswing, my bias is to get interested pretty early in gestation — not necessarily to use the language for a client project, but to get a sense about where language (and compiler) development is going. I’m not likely to use Ada or even Haskell when building something that others will need to maintain, but, as an example, looking at how Haskell handles lazy evaluation and “first-class” functions is fascinating, and broadens the knowledge of the team.

So perhaps the better questions are about when to use a language for a project that will be released into the wild — and when to stop doing so, as a language’s star is falling? The answers to both are really the same: when maintenance and long-term expertise is easy and relatively cheap to find.

We’d love to be in lifetime engagements with clients. And many of our clients are with us for many years. But we don’t assume that, and we don’t want to build something that will create hassles for the client later. So that means, no matter how much we love Forth, we’re probably not going to use it to build a web application. There just aren’t enough people out there to support it. (Plus, that’s not really a great use of the tool.)

But let’s take a tougher example: perl. Fifteen years ago, it was everywhere. If you didn’t know it, you weren’t considered serious about building for the web. As PHP has usurped some of that space, perl remains a widely-used language (although more and more, it seems to be confined to the back-end and server side).

But man, I love perl. It has an ability to work with bits of data and patterns that is perhaps matched, but rarely surpassed. Contrary to some of its reputation, it can be elegant — but it doesn’t force it. (Why is there so much bad perl code? Bad perl coders.) And the CPAN archive of modules and third-party libraries is peerless.

What to do, then? Objectively, perl’s fortunes are falling. Has it passed the threshold of use on a major project? Well, as of this writing, I’d say no — but it’s getting close. The thumb on the scale that balances cost-benefit of using a language for a project is getting kinda heavy. It’s probably in the space where we will build and maintain perl-based projects that are already in that language, but are unlikely to starting something from scratch in it.

Which is sad, but for every one of those, there’s an Objective-C or a C# that’s climbing up the charts. Goodbye Esperanto, hello Mandarin.

Finally! finally in PHP 5.5

PHP 5.5.0 was released yesterday, and there are a handful of helpful new features. Among them, there is one that looks the best to me — the try-catch block has the finally block added. After all, if you’re doing exception handling in your code with try-catch (and if you’re not, you really should be), there are often scenarios in which you want to execute some arbitrary code at the end of the block, regardless of whether an error got thrown or not.

In some cases, you can put it outside the try-catch block (at the end, of course), but there are at least two circumstances where that’s less-than-optimal. First, if the program flow is altered in the try or catch, yet you want to tack on some code at the end, you’re in luck. But in our case, most of the time, it’s a readability issue. We try to group code conceptually when we write, much as we do when writing in English. That means we use sentences and paragraphs. Well, when coding, we do the same thing. And the addition of the finally block will make that even easier.

Another nifty functional help is the addition of the list form in foreach structures.If you work with nested arrays, you can now unpack them in the foreach construct, exposing the underlying variables much more easily. Like the finally block addition, it’s not as though you couldn’t code around this limitation, but when you don’t have to, code gets more readable.

In a deja-vu moment for C programmers, you can now dereference arrays and string literals to access specific items and characters. So in PHP 5.5, ‘Square’[1] equates to ‘q’. Not too shabby.

You can now pass a function call to empty() to evaluate it, which is another keystroke-saver when coding. So if you have a function foo() that may return data or may return, say, false, you can evaluate empty(foo()) and see if false came back. Again, a minor assist, but an assist nonetheless.

There are other features in this release, too, including a new Zend optimization caching extension, some enhancements to the GD graphics library, a new yield keyword that allows you to do simple iteration without using as much memory, a class function that gives you the unqualified class name, and more.

It’s good to see PHP continuing to evolve and grow — it has come a long way since I first used it fifteen years ago!