Improvisation is the name of the game, and we tend to do a lot of it with plugins and themes. In that process we tend to modify functions by adding more variables to incorporate changes in them. However, unlike most of the other languages, PHP allows users to set default values for variables passed to a method too.
As a developer when you start out coding, you have a certain number of things a function will require in order for it to work, some may be optional too, so you set out to create a method signature similar to the one below.
function do_something($var1, $var2, $var3, $var4 = false, $var5 = '') {
//process business logic here
}
Now, say you release your plugin or theme and get more feedback on features and other improvements. If the features or improvements suggested require you to change the method signature to incorporate new variables and you use default values, you are in a bit of a spot.
So what is the best way to avoid such situations? In my opinion, if you use a function which accepts variables, it could easily scale to accept more parameters without breaking anything by accepting an array as a single parameter. The array would have to be built up either internally in the code somewhere or externally through the user.
So you could rewrite the above logic as below:
function do_something($args = array()) {
$myvar = (array_key_exists('mykey', $args)) ? $args['mykey'] : get_default_value('mykey');
//process business logic here
}
Now, you would not expect a user to pass an array while using your non-widget based plugin in their themes, so you would have to provide users with an options page which will allow them to set the values they want to be passed to the function, and then build a Facade function internally which will then read all the option values and pass it on to the main function to be processed.
I hear people saying that they can fetch the options from WordPress inside the function itself and there is not need for this Facade, however, in my experience of over 11 years in the software industry, I have learnt one important thing, never mix anything with business logic.
If a function is supposed to perform a task, let it perform only that and nothing else, that way you can reuse the function elsewhere without having to constantly rewrite it to adapt to different things.
I have seen several plugins which make use of arrays and several which do not. I would definitely be interested to learn on how you approach this, the comments form is open.
Update: From the comments below, many users mistook me. I never said that users cannot use wp_parse_args. However, being an OOPS developer, I stick with my above post and say that you should keep business logic separate from processing logic, no matter whether it is WordPress or any other platform, that is the basic fundamental I learnt in OOPS, and I do believe OOPS is the best fundamental and way to go forward. I expect arguments on that.
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