Agile Web Development with Rails 7.2

Ruby Idioms

A number of individual Ruby features can be combined in interesting ways. We use these common Ruby idioms in this book:

Methods such as empty! and empty?

Ruby method names can end with an exclamation mark (a bang method) or a question mark (a predicate method). Bang methods normally do something destructive to the receiver. Predicate methods return true or false, depending on some condition.

a || b

The expression a || b evaluates a. If it isn’t false or nil, then evaluation stops and the expression returns a. Otherwise, the statement returns b. This is a common way of returning a default value if the first value hasn’t been set.

a ||= b

The assignment statement supports a set of shortcuts: a op= b is the same as a = a op b. This ...