Readable Code: Name Everything

Consider the following code samples.

// Specimen A 

if ($forceClose !== ' ' && $forceClose !== NULL && $issues['forcedClose'] && $forceClose > 0) 
     $this->saveAttrForUser($user, 'forced_close', $forceClose);
     if ($forceClose == '1') 
         Log::saveWrite("App killed");
// Specimen B
// note the prefix 'b' indicates type Boolean, the prefix 's' indicates type String
$bGotValidMessageFromClient = !($sForceClose !== ' ' && $sForceClose !== NULL);
$bAppPassedExitMessage = $aIssues['forcedClose']; 
$bExitWasForceful = ( (int)$sForceClose > 0);
$bAppWasForceClosed = $bExitWasForceful && $bGotValidMessageFromClient && $bAppPassedExistMessage;

if ($bAppWasForceClosed) 
     // A comment here that would mean something...
     $this->saveAttrForUser($sUserId, 'forced_close', $sForceClose);
     $bForceCloseWasAKill = ($sForceClose == '1');
     if ($bForceCloseWasAKill) 
         Log::saveWrite("App killed");
These two samples contain the exact same logic. The former is more direct, essentially it inlines all of the variables in the latter. And that is why it is worse. A variable serves as a unit of abstraction, and a well-named variable is a comment; thus having more variables is better. In fact, all if conditions should the form if ($bSomeVariable) {, that is, never put a complex expression within the parentheses of the if. If the logic is particularly complex then use multiple variables, as seen in the sample above.

All if conditions should the form if ($bSomeVariable) {

At first glance, the bottom example is longer and may look intimidating. But it is superior because it exposes its internal logic. Try deciding what the top code does, and what ‘1’ indicates in that code. Then consider the bottom code. The top is an actual code sample.

And while we’re adding in these extra variables, let’s name our variables clearly. Programmers seem to have some unspoken assumption that variable names need to be less than 10 characters and not have prepositions… Maybe this made sense when you had an 80 character wide monochromatic screen with no form of autocomplete, but technology has made that trend obsolete.  I suspect most people would try to turn the variable name $sLinkToUniversalDownloadPage into something like $sUniversalDownloadLink which is inferior because it is ambiguous (is the link universal or the download universal?).

Or, for example, what would a function named “OpenFileLock” do? Is it opening a lock on a file? Is it filing a lock (in some kind of lock registry)? Is it locking an open file? Each of the three words in the title can be read as a multiple parts of speech (i.e. verb, noun, adjective, etc). Or perhaps FileLock is an existing class in this codebase. Prepositions here would make all of the difference.

Name everything; name it well.