In Ruby, individual accessor and mutator methods may be defined, or the metaprogramming constructs attr_reader or attr_accessor may be used both to declare a private variable in a class and to provide either read-only or read-write public access to it respectively.

Defining individual accessor and mutator methods creates space for pre-processing or validation of the data

      class Student
        def name
          @name
        end

        def name=(value)
          @name=value
        end
      end

Read-only simple public access to implied @name variable

      class Student
        attr_reader :name
      end

Write-only simple public access to implied @name variable

      class Student
        attr_writer :name
      end

Read-write simple public access to implied @name variable

      class Student
        attr_accessor :name
      end