Question

What do the vast majority of Rails shops do? Since Ruby allows for either I’m sure there is a set standard I should probably fixate on making a habit since I’m just starting out with Rails.

According to Pragmatic Agile Web Development With Rails (4th Edition):

In Rails applications, you’ll find that most method calls involved in
larger expressions will have parenthe- ses, while those that look more
like commands or declarations tend not to have them.

So which is it? Or is it the wild west out there?

Answer 1

The Rails contributing style guide seems to favor

my_method(my_param)

over

my_method my_param

But most of the code I’ve seen seems to buck that trend. I would definitely say that you shouldn’t use open parentheses for a method call without parameters. The one guiding principle I’ve noticed is to emphasize code human readability. That leads me to the following conclusions:

Don’t use the parentheses if
Your method call has no arguments

my_object.my_method

Your method call is the only thing on the line

my_object.my_method my_params
form.submit "Create"

Do use the parentheses if
Your method call is on the same line as a number of method calls

my_object.parse(my_arguments).join(", ").chomp

However, there are different conventions for different situations that you’ll probably only see by looking at a lot of code. For example, methods that execute within a class definition mostly don’t use parentheses, and have each argument on a different, indented line:

validates     :first_name,
              :presence => true,
              :format => { :with => /\S./ }