Ask HN: The most fun and beautiful code you know of?
What is the beautiful, interesting, suspenseful, fun code that you would rather curl up to read with a cup of coffee than most any other writing?
What is your "nightstand" code? Funny seeing this, because I was at my local Borders earlier and decided to give that Beautiful Code book a shot. I've seen it on the shelf for quite a while, but those books don't tend to turn my crank, so to speak, so I had never before really considered it. I only read the first and the third essay, but I must say, wow! The third essay, for instance, takes a simple 12 line implementation of quicksort in C (which is already quite beautiful), and through a series of well explained transformations, arrives at a four line proof (as in, it's C code that is equivalent to the recurrence relation, and eventually the summation, we all solved in our CS classes) of the average case complexity (~1.4nlgn comparisons) of the quicksort he started with. That is what I would consider "nightstand" code, or at least a nightstand essay about code. It was actually entertaining, to the point that you don't realize you are solving a recurrence relation in C form until the end, when the parallel becomes obvious. I only had a chance to skim the other topics, but I'm actually considering buying it, because it really was a blast to read. Oh and to post some actual code... Definitely not _the_ most beautiful code I've written, but I still enjoy this little function for some reason. It's just pretty to me. I think it's been posted before, but it's relevant. You can see Jon Bentley give a talk on that here: UTF-8 encoding in 6 lines, from ezxml: The UNIX v6 kernel (Lions book). Every page brims with the excellent, hard tradeoffs required to shoehorn what we'd recognize as a modern system onto a 128K 16-bit machine. My own code... (Not because it's perfect and beautiful, but just because I wrote it and understand it.) My own code that's common throughout all of my software. Report writers, data base update objects, data formatting routines, form processors, string & array handlers, special logic algorithms, and especially, code generators. The more I read these, the better I know them. The better I know them, the easier to improve and extend them. The more I extend them, the better my software gets and the less of it I have to write to get anything done. Leverage. I literally have a folder of all this stuff on my nightstand or in my backpack all the time. Duff's device. It opened up my eyes for the beauty of C and insanity of compilers: http://en.wikipedia.org/wiki/Duffs_device Usually I find API documentation more inspiring than actual code. It's higher-bandwidth. That said: - Some bits of On Lisp - Haskell's SYB and Parsec libraries - MINIX (2; have yet to play with 3) Solutions in Programming Pearls. Each solution is iteratively improved with the proper reasoning. http://www.amazon.com/Programming-Pearls-2nd-ACM-Press/dp/02... Anything that: * Doesn't repeat itself. This includes languages which involve marking out blocks of code once for the interpreter and the second time for humans. * Is short, because it doesn't reinvent common modules, and modularizes out general logic. * Uses descriptive names, including using dictionary keys rather than vague list element numbers. A good test is if you can show the code to someone who doesn't work in computing and have them understand it. ZS had a talk on this where he showed lawyers SOx code and received feedback on the rules, changes to the order, etc. * Uses tree structures for tree structured data (eg, etrees and xpath) rather than treating such data as strings and using RegExs. * Has docstrings. Shakespeare. It exists. Seriously. It's as beautiful as Shakespeare, but not very fun, sadly. http://en.wikipedia.org/wiki/Shakespeare_(programming_langua... The art of computer programming. Not because it's direct computer code, but because when I'm reading it past code i've written starts swirling in my head.
Sort of one of those "ahhh fantastic" moments. /* fun only /
#const HellIsAHotAndFieryPlace=1
while (HellIsAHotAndFieryPlace)
printf("The end is near\n") ; / yes it did make me laugh when I read it in Atari St user */ Very few people will get this reference, but when I had access I used to read the genweb3 code. It's like a whodunnit because there are no comments. :) pseudocode all throughout cormen... I appreciate industrial code the same way I appreciate a ferrari - without looking at the engine Shakespeare. It exists. Seriously. It's as beautiful as Shakespeare, but not very fun, sadly. http://en.wikipedia.org/wiki/Shakespeare_(programming_langua... c99shell. It's a PHP trojan horse of sorts written by Russian hackers. Beautiful, rare, dangerous and awesome. OpenBSD, Django and code written by Niels Provos. Google.
All it does is take a query string template of sorts, grab the values to plug in, and then return an actual query string. For instance, if you had this on your page somewhere: function addparams(query) {
return query.replace(/(&?)([^&=]+)=([^&]*)/g, function(m, amper, key, id) {
var val = document.getElementById(id).value;
return val.length > 0 ? amper + key + "=" + escape(val) : '';
});
}
Then we used it when doing some kind of ajax update. Assuming jQuery, (although that wasn't the case) something like this: <input type="text" id="first" value="defaultfirst"/>
<input type="text" id="last" value="defaultlast"/>
Which would make an xhr GET request to: $.ajax({
url: "/path/to/page",
data: addparams("fn=first&ln=last")
});
Nothing remotely complicated or amazing like the regex that finds prime numbers or the 12 line quicksort, but I just think the function is aesthetically pleasing. /path/to/page?fn=defaultfirst&ln=defaultlast
if (c < 0x80) *(s++) = c; // US-ASCII subset
else { // multi-byte UTF-8 sequence
for (b = 0, d = c; d; d /= 2) b++; // number of bits in c
b = (b - 2) / 5; // number of bytes in payload
*(s++) = (0xFF << (7 - b)) | (c >> (6 * b)); // head
while (b) *(s++) = 0x80 | ((c >> (6 * --b)) & 0x3F); // payload
}