What is the favorable naming convention for methods or properties returning a boolean value in Ruby?

Question

I've seen all of these:

• is_valid

• is_valid?

• valid?

Is there a preferred one?

EDIT: More conditionals:

• has_comment has_comment? comment?

• was_full was_full? full?

Please do add more descriptive examples.

Answer 1

I think the convention is mostly to add a '?' at the end of the method instead of 'is'

• valid?

Answer 2

In favor of trying the code to be 'natural language' like, is_valid? should be most suitable for me. Lets show an example:

if @order.is_valid? @order.save end