How does PHP5 fare with earlier versions of the language

Question

I would like to learn PHP for web development but have been drawn back because of comments like the following^*:

• PHP is good but generates spaghetti code
• PHP is nice but Python is marriage material
• PHP lacks stuff that you get in other languages like C# or Java

But for PHP5 I have seen some promising comments. So, my question is: How does PHP5 fare with earlier versions of the language and is it good enough now to learn for web development.

_{* Comments are just for reference not to incite a flame war. No comparison of PHP with other languages is asked for here. Please comment just on PHP5 and how it compares with earlier versions.}

Answer 1

When discussing languages, these two Stroustrup quotes always pop in mind:

Anybody who comes to you and says he has a perfect language is either naive or a salesman.

and

There are only two kinds of languages: the ones people complain about and the ones nobody uses.

Now to the question at hand. Most of the hate is mostly directed at PHP4. PHP5 was first released in July 2004 (beta a year earlier) and the last version of PHP4 is 4.4.9 released on August 2008. There is no valid reason to use PHP4 anymore, unless of course you maintain some legacy app. PHP4 is no longer supported by the PHP group, and we all hope it fades away soon.

The gap between the two versions is bigger than it usually is between two major releases, as the engine behind the interpreter was rewritten from scratch, and included a new object model. The release of PHP5 roughly coincided with the release of MySQL5, a major overhaul of MySQL. PHP is usually coupled with MySQL and the fifth version of both addressed several issues and brought them up to speed with the competition. MySQL is also subject to FUD comments, but, well, it's the database behind Google's AdWords.

PHP 5.3 was a major release in everything but name. A lot of features that where intended for PHP6 found their way in 5.3 and for every 5.2 developer out there I'd strongly advise to migrate to 5.3+ sooner than later. The current release, 5.4, includes some awesome features (amongst others):

• Namespaces,
• Late static binding,
• Jump labels (limited goto),
• Native closures,
• Nested exceptions,
• Traits

Now for your specific comments:

PHP is good but generates spaghetti code

That's absolutely not true. No language generates any kind of code, it's always up to the developer to screw up, spaghetti code is possible in every language out there. What is true though is that PHP has a very low entry barrier compared to other popular languages, hence it's a lot easier for inexperienced developers to write bad (but working) code. But that's a side effect of every easy to learn language.

Furthermore PHP does not enforce any particular style or paradigm, and it's always up to you to decide what to do. I've always thought of this as a good thing, while others see it as a valid point of criticism. You'll have to decide for yourself.

PHP is nice but Python is marriage material

PHP lacks stuff that you get in other languages like C# or JAVA

Yes it does. And general-purpose language X lack a lot of stuff that you get in PHP. Like being portable across operating systems AND across http servers, and support for every imaginable third party library that would be useful in a web development environment. You have to understand that PHP doesn't lack of anything important, if it did it would have died a long time ago. The comparison between general-purpose language X and other multi-purpose languages to PHP is a fallacy, apples and oranges. Although PHP offers some facilities to support the idea that it's general-purpose, it's not, it's a web language.

You have to keep in mind that PHP's evolutionary path is quite different from general-purpose language X: PHP grew and evolved, it wasn't designed. Every time a feature is added to the language is out of actual necessity, not in accordance to some imaginary ideal of what a language should be. Languages are first and foremost tools, and PHP is perfect as such.

I don't have anything against general-purpose language X, I'm all for choosing the right tool for the job. I've always mixed and matched, and I'm coding in Java and Python too, sometimes in parallel with PHP. But PHP is the only one I'd ever consider marrying. :)

If you're considering starting with PHP, you should of course start with the latest stable version, as you would in any other language.

Answer 2

PHP has been "good enough" for web development for a long time. As with any programming language, the quality of the code hinges on the skills of the developer writing it.

A common criticism of PHP is that its flexibility makes it easy for inexperienced developers to write bad or "spaghetti" code. This is largely because it tries to simultaneously embrace a number of paradigms that occasionally conflict, are poorly implemented, or do not mesh well.

• Server-side scripting (PHP) juxtaposed with client-side code (HTML + Javascript) without modularity is common, almost encouraged, to the detriment of clarity & readability.

• It's commonly written in an imperative style, but provides mechanisms for object-orientation. This easily results in mixed styles and can often lead to bad design.

• Object-oriented design was (in my opinion) poorly supported in PHP4. This is one area that PHP5 has significantly improved upon (e.g. with access modifiers, abstract classes, improved scope resolution.)

• PHP's dynamic typing enables run-time errors that could be eliminated with static type-checking. This is inherent to the design of all PHP versions and will not be changing any time soon; the burden of validating object types is left to the programmer.

The changes in PHP5's OOP model do a lot to encourage good design moving forward, but do not add any disincentives to discourage the bad practices mentioned above.

Answer 3

PHP has some significant issues within itself, but those are primarily of the annoyance variety: Its library is inconsistent and somewhat schizophrenic, it lacks strings as first class objects, things like that. It does not force you to write poor code, and it does work fairly well for what it does -- write web pages. Your PHP will be as good as you strive for it to be; it's quite possible to write PHP that's terribly procedural and looks like C code, and it's quite possible to write PHP that's overly Object Oriented and looks like Java. As someone who develops in PHP daily, I like some things about it and hate some things about it and can't wait for some 5.4 functions (like Traits and sane function return dereferencing), but I'd wholeheartedly encourage someone who's thinking about picking it up to do so.

Answer 4

php5 is a much improved version of php4.

Most but not all php4 code works in php5.

What really changed was the much improved Object Model, which fixed a lot of limitations and quirks inherent in the previous OO implementation, but, which is largely incompatible with preceding versions.

Docs here

The other comments have some validity but are not a "no go"

"PHP is good but generates spaghetti code" -- you can generate all sorts of pasta in any language, but, php, does nothing to discourage the inexperienced coder writing a rats nest of unstructured code. Conversly you can write nice code in any language, skilled programmers have no problem writing clean well structured php.

"PHP is nice but Python is marriage material" -- Its a nice language but there are several diverse web frameworks all of which have extremely good points, but, none of which has really taken off, which is all fine, but any Python/framework of your choice combination will always be a niche skill.

"PHP lags stuff that you get in other languages like C# or JAVA" -- php has the most diverse and well implemented library support of any language except perl. There are a few blank spots like statistical analysis, and, vector processing. But generally if you want to do something a quick search of PEAR will locate a library which does it. The language itself is simpler then C# or Java -- but the simplicity of the basic syntax plus "Duck Typing" means you can do anything in php you can do in Java in a more readable and elegant way.