Skip to main content

I prefix my variables with their type!

Why 'Systems Hungarian' makes sense.

As a developer, if you prefix the variable type you are clearly in the minority - I for one am a proponent of the Systems Hungarian notation, not the Apps Hungarian notation.

The merits become apparent when reading other people's code, or when you look at your own code months/years after. Properly naming variables can be hard, the type is not always obvious from the name itself and left to individual interpenetration. Prefixing completely removes any uncertainty, it immediately reveals the type of the variable, and the developer reading the code does not have to go through the mental friction of inferring from either the name, or from how it is being used in the context, or traversing to where the variable was defined.

For weakly typed languages like JS/Python it has the huge additional benefit of making debugging that much easier, when one treats the prefix as the intent of what should be the value stored it reveals possible issues immediately when stepping through code.

When the end goal is the benefit to 'other' developers reading your code Systems Hungarian also makes perfect sense. Yes, it does mean some time getting used to it, but it's no different then any other coding pattern you habituate yourself to.

We end up gravitating towards the familiar and end up finding other patterns ugly, this in my opinion is the root cause of the negativity against type prefixing, or any naming conventions you don't use everyday. In the end I prefix because it has increased my own code readability to me.

JavaScript and Apex variable prefixing

Variables are prefixed using letters from primitive/built-in types ( and `f` for functions - this keeps the rule list logical and consistent:

// NOTE: use ``

var nYear; // for Numbers (`[object Number]`)
var bGender; // for Booleans (`[object Boolean]`)
var sName; // strings (`[object String]`)
var oTable; // objects (`[object Object]`)
var mSKUMap; // objects (`[object Map]`)
var stColors; // objects (`[object Set]`)
var aScores; // for arrays (`[object Array]`)
var fAge = function () {}; //for functions (`[object Function]`)

I was happy to find at least one other person thinks the same: what-do-you-mean-by-the-initial-letter-on-javascript-variables-functions.

Apex primitive types variable are prefixed as follows

Blob blBlobieFoo; 
Boolean bActionVisible;
Date daDateOnly
Datetime dtStartDateAndTime;
Decimal deAgeOfUniverise;
ID idUserRecord;
Double dBiggerNumber;
Integer iUserAge;
Long lTurlleAge;
Object oUserRecord;
Object oContentList;
Object oContentMap;
String sFirstName;
Time tAlarm;

mUserAge(...); // undecided on this one

What are you thoughts on this? But please no hating.


Popular posts from this blog

Opera SOCKS Proxy Setup Issues

SOCKS error: Connection closed by remote server When setting up SOCKS only proxy in Opera web browser make sure to specify the IP address instead of your fully qualified domain name (FQDN). Using a host name will not work and Opera simply fails to connect to the proxy server. Sample working setup screen shot with a Dante proxy server , note that HTTP, HTTPS, FTP, SSH options are left blank. Bug DSK-364301 has been filled with Opera, if it has been a while since this post and the issue still not fixed feel free to add your word of encouragement by emailing :)

Storing passwords in PuTTY

How to save SSH username/password for auto login in PuTTy The answer is you can't do least in plain PuTTy. However there is an awesome fork with that let's you store the username and password and other additional features called KiTTy.

So grab yourself a copy and +1 this if you do, thanks.

Duplicate value found: duplicates value on record with id: <unknown>.

System.DmlException: Insert failed. First exception on row 0; first error: DUPLICATE_VALUE, duplicate value found: <unknown> duplicates value on record with id: <unknown>.The above error is triggered in the database layer and caused by a trigger or workflow outside of your main code of block that is bubbling this exception. This is rather difficult to track down especially if you are unfamiliar with the code, I am sharing my procedure in the hopes this saves you time - if you find this helpful drop me a line or follow me on twitter @danielsokolows. This error is caused by unique field constraint on the object, so the first step is to examine the object and locate the API names of all unique fieds. You can do this through SF direclty 'Setup < Customize &lt <object being inserted> &lt Fields' or by downloading the `src/objects` metadata information and searching for <unique>; I preffer the latter and actually download ALL matadata information f…