Saturday, October 2, 2010

8 Tips to Improve Your Golf Game

I wasted more time golfing this week than I should have. No, not real golf... code golf. Trying to write small programs in the least number of keystrokes can be fun, challenging, and sometimes even addicting. It's not about writing pretty code or code that's easily-understandable. It's all about cramming as much code as you can into the least number of characters. While some languages golf better than others, you can still write impressively small code in your language of choice if you're familiar enough with the intricacies of its behavior. Here are 8 tips to improve your golf score when golfing with PHP:

Use short tags.
Using <? instead of <?php and using <?= instead of <?echo will both save you 3 characters.

Avoid initializing variables if possible.
Uninitialized variables assume the value 0, "", or false depending on the context in which they're referenced. $x=0; is 5 characters too much!

Know your function aliases.
A few functions in PHP are known by multiple names. join() for example is 3 characters shorter than implode().

Don't repeat yourself unnecessarily.
Consider saving the name of an oft-used function to a variable if you use the function more than once, but the function name needs to be more than 4 characters and used at least twice for any savings. $c=chop;$c($a);$c($b); is actually 4 characters more than just calling chop() twice.

Love bare literals.
PHP treats bare literals as strings, so you can save 2 characters by dropping the quotation marks.

Don't love bare literals.*
Use bit negation and binary string literals to save an extra character. is better than " ", and is definitely better than "\n".

Take advantage of side effects.
Something like $b=1;$x=80;, where $b is acting as a Boolean, might be written as $b=$x=80;. $x is assigned 80 and then assignment operator returns that value, which is then assigned to $b. Non-zero integers are considered true, so the two are semantically equivalent with a savings of 2 characters. Another example is echo$x--,"bottles of beer";, which is shorter than echo"$x bottles of beer";$x--;.

Reduce incrementally.
Write non-golf code first to make sure you fully understand the problem and your solution, then rework your code smaller and smaller in incremental steps. Don't forget to verify its correctness after each reduction.

Consider different approaches to solving the problem.
You might think to choose an array if you need a sequence of character values accessible by a numeric index, but storing them as a string might be just as effective. Then again, it may not depending on how that choice affects how you work with the data later. Don't hesitate to try both approaches to see where they lead you.

* Don't... negation... get it? Ha ha! Yeah, don't worry. I won't quit my day job.