Naming conventions for boolean attributes

I want to write code that others easily can understand as well.

Do boolean attributes like hide_email or email_hidden have a convention style?

Upvotes: 20

Answers (4)

Reputation: 18037

I think of it like this:

A boolean attribute should answer a simple yes/no question.
Asking "is?" is a simple way to ask a yes/no question.
So a boolean attribute can be though of as a small phrase, containing is. e.g. is <attribute_name> or <attribute_name> is <something>
Then just remove the is because Ruby prefers the ? suffix for "is"-style method names (see below for more), leaving you with just <attribute_name> or <attribute_name> <something>.

So, for your specific case, name your attribute like this:

Start with the question "is email hidden?" or "email is hidden?". Which can be represented in code as: is_email_hidden or email_is_hidden.
Remove the is and, either way, you're left with email_hidden

Why?

Ruby on Rails defines a "predicate" method (one that ends in a ?) corresponding to all boolean attributes and returns true or false. So, while your attribute is named email_hidden in the database (somewhat stark feeling, no doubt) you can and should reference it as email_hidden? in your code. Both for clarity and because this is the idiomatic Ruby on Rails way.

Upvotes: 35

Reputation: 3723

Taking these two examples of names you gave:

hide_email would be a good name for a method performing such a task, a method that executes all the procedures to hide an email in the scope of your system. But it would never be a good name for a boolean method returning the state of an e-mail.
email_hidden?, with a question mark (?) at the end, would be the correct name for a boolean method indicating if the e-mail is hidden or not.

Always consider Ruby conventions if you really want to write good code. They will help you even when thinking about the processes in your system.

Upvotes: 3