Zaemis

What happens if you don't have all the arguments handy for a function, but you want to give whatever arguments you do have now and then provide the rest of them to the function later? This is called currying , and is a core concept in functional programming. It's messy, but possible to curry functions in PHP now that closures have been added . First, let me show you how currying looks in a functional language. Here's a basic example in OCaml/F#: let do_math op x y = match op with '+' -> x + y | '-' -> x – y | _ -> failwith "Invalid op" let add = do_math '+' let inc = add 1 let dec = add (-1) ;; A function named do_math is defined that accepts an operator and two operands. The function's return value will be either the sum or difference of the operands, depending on whether the given operator is + or - . Notice how do_math is then called with a single argument. OCaml doesn't raise an error; it simply ret...

Ever wonder if there is an MD5 hash the same as the original input? Nope, me neither. But Mr. Kember does and he's asking the world to help him find out if such a thing exists. There's no fame if you find it for him (he's humbly named it the "Kember Identity" already)—but you might make a little cash. Check out his web page for the details. Go ahead and enter his contest if you're feeling gullible lucky! The MD5 algorithm returns a fixed-length 128-bit hash, so there are 2 128 possible values. The hash is typically expressed as a series of 32 hexadecimal values. Since the input string and its hash must be the same to reflect the Kember Identity, you wouldn't need to test random strings like "ruby on rails rots your brain"; you only need to test strings that are 32-characters long and contain the numbers 0 though 9 and letters a through f like 8d112b3c68248c12f178188c1b921ec1 . Kember suggests testing values at random because the range of ...

Proponents of Object Oriented Programming feel the paradigm yields code that is better organized, easier to understand and maintain, and reusable. They view procedural programming code as unwieldy spaghetti and embrace OO-centric design patterns as the "right way" to do things. They argue objects are easier to grasp because they model how we view the world. If the popularity of languages like Java and C# is any indication, they may be right. But after almost 20 years of OOP in the mainstream, there's still a large portion of programmers who resist it. If objects truly model the way people think of things in the real world, then why do people have a hard time understanding and working in OOP? I suspect the problem might be the focus on objects instead of actions. If I may quote from Steve Yegge's Execution in the Kingdom of Nouns : Verbs in Javaland are responsible for all the work, but as they are held in contempt by all, no Verb is ever permitted to wander about ...

Someone asked me, "What do you think about the Oracle/Sun buyout as it pertains to MySQL?" Well, since you're asking... I thought it was bad for MySQL when Sun bought them despite what others were saying at the time. It turns out I was right. I think Oracle will be worse, and this time the blogosphere are saying it'll probably be bad. Now the question is, just how bad will it be? Here's my predictions: I'm sure Oracle realizes they need to tread lightly on the subject of MySQL or else risk the wrath of the open source community. They may integrate some of MySQL to improve Oracle, but they won't promote the continued development of MySQL proper (Berkeley DB anyone?). That is, Oracle won't actively kill MySQL, but they'll let continue to languish the slow and painful death that began before Sun came along. I don't see a financial benefit to Oracle for keeping MySQL healthy. If MySQL does survive, it might be branded as "Oracle Lite....

Some employers look favorably on certifications, or even require them; other employers could care less. Some people are certified in something but clueless when it comes to actually using the technology. Some people get certifications like they're going out of style just because they can. Some people cheat on the exam . So how much stock should one put in certifications? I'm not sure I know the answer to that. I guess it depends on the certification, what the testing environment is like, who runs the certification program, etc. Today I ran across PHP-Rocks during my daily web-surfing. It's a small site that offers a set of tutorials ranging from beginner up to advanced, and a PHP "certification" exam. The exam piqued my interest. It was free to take, and I was curious as to what type of questions it asked, so I signed up. Of course I often sign up a dummy account and fake email address when I do such things because I don't intend on becoming a regu...

It slipped quietly under the radar for some. For others, it raised quite a stir. No, I'm not talking about PHP's implementation of namespaces (a battle that's finally done and over much to everyone's relief). I'm referring to the infamous goto statement. Many programmers have had the " goto is evil" mantra drilled into them from an early start. The basis of this can probably be traced back to Edsger Dijkstra's March 1968 letter to the editor in Communications of the ACM (though he wasn't the first to argue against goto ). Dijkstra felt the proliferation of goto at the time was producing unmaintainable "spaghetti" code. Fast-forward more than 40 years later and the controversial feature is still alive and well... and about to make its debut appearance in PHP. I found myself discussing some of the new features in PHP 5.3 with a friend a few days ago after he read my previous post about anonymous functions and closures . Our conversatio...

Of all the new goodies that are promised in PHP 5.3, the two which I think I am the most excited about are anonymous functions and closures. Anonymous functions are functions that are defined without being bound to a proper name. Typically, anonymous functions are used only a limited number of times and for a specific purpose; you could think of them as "throw-away" functions if you'd like. Let's consider the following example which illustrates a standard function used as a callback: function percentVowels_callback($word) { $word = strtolower($word); $chars = count_chars($word); $numVowels = 0; foreach (array("a", "e", "i", "o", "u") as $vowel) { $numVowels += $chars[ord($vowel)]; } return $numVowels / strlen($word); } $animals = array("aardvark", "elephant", "iguana", "orangutan", "urchin"); $percentVowels = array_map("percentVo...

I was thinking today about database APIs when inspiration struck. I ended up hacking out the following class, which I think demonstrates a rather interesting approach to interfacing with a database (interesting enough at least to post here). class DBQuery implements Iterator { protected $_db; protected $_query; protected $_result; protected $_index; protected $_num_rows; public function __construct($host, $dbname, $username, $password) { $this->_db = new PDO("mysql:dbname=$dbname;host=$host", $username, $password); } public function __get($query) { $this->_query = $query; $this->_result = $this->_db->query($query); return $this->_num_rows = $this->_result->rowCount(); } public function quote($value) { return PDO::quote($value); } public function __call($query, $values) { $this->_query = $query; $this->_result = $...

I've been having a hell of a time fighting with some Perl code at work lately. I tossed together a humorous Perl demotivational poster to release some of my frustration, and thought others might appreciate it. But why stop there? There are other languages worth making fun of besides Perl! So, I tossed together some more snarky posters to be fair.

I've been tagged by Chris Cornutt and Jeff Jones to share some things you probably don't know about me. (It's nice to see chain mails flow through the blogosphere too, eh?) So, here's seven little-known facts about yours truly... My first career choice was to be a diocesan priest, and I briefly attended Seminary after I graduated from high school. My family isn't overly religious, and my parents didn't push me to go; I think I just like to help people and felt drawn to the rich history of the Roman Catholic Church. Life has a funny way of playing out differently than we intend for it, doesn't it? After I left seminary, I attended a state university and majored in elementary education with a concentration in music history and literature. I'm not overly fond of children, though, so I didn't complete the program. I would only need to take two more classes to be a state-certified elementary teacher. I studied French for 5 years in high school...