Class: Class

Inherits:
Object show all
Defined in:
lib/shopify/extlib/class.rb

Overview

Allows attributes to be shared within an inheritance hierarchy, but where each descendant gets a copy of their parents’ attributes, instead of just a pointer to the same. This means that the child can add elements to, for example, an array without those additions being shared with either their parent, siblings, or children, which is unlike the regular class-level attributes that are shared across the entire hierarchy.

Instance Method Summary collapse

Instance Method Details

#cattr_accessor(*syms) ⇒ Array[#to_s]

Defines class-level (and optionally instance-level) attribute accessor.

Parameters:

  • *syms (Array[*#to_s, Hash{:instance_writer => Boolean}]) —

    Array of attributes to define accessor for.

  • syms (Hash) —

    a customizable set of options

Options Hash (*syms):

  • :instance_writer (Boolean) —

    if true, instance-level attribute writer is defined.

Returns:

  • (Array[#to_s]) —

    List of attributes that were made into accessors



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# File 'lib/shopify/extlib/class.rb', line 94

def cattr_accessor(*syms)
  cattr_reader(*syms)
  cattr_writer(*syms)
end

#cattr_reader(*syms) ⇒ Array[#to_s]

TODO:

Is this inconsistent in that it does not allow you to prevent an instance_reader via :instance_reader => false

Defines class-level and instance-level attribute reader.

Parameters:

  • *syms (Array) —

    Array of attributes to define reader for.

Returns:

  • (Array[#to_s]) —

    List of attributes that were made into cattr_readers



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# File 'lib/shopify/extlib/class.rb', line 38

def cattr_reader(*syms)
  syms.flatten.each do |sym|
    next if sym.is_a?(Hash)
    class_eval(<<-RUBY, __FILE__, __LINE__ + 1)
      unless defined? @@#{sym}
        @@#{sym} = nil
      end

      def self.#{sym}
        @@#{sym}
      end

      def #{sym}
        @@#{sym}
      end
    RUBY
  end
end

#cattr_writer(*syms) ⇒ Array[#to_s]

Defines class-level (and optionally instance-level) attribute writer.

Parameters:

  • Array (Array[*#to_s, Hash{:instance_writer => Boolean}]) —

    of attributes to define writer for.

  • syms (Hash) —

    a customizable set of options

Options Hash (*syms):

  • :instance_writer (Boolean) —

    if true, instance-level attribute writer is defined.

Returns:

  • (Array[#to_s]) —

    List of attributes that were made into cattr_writers



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# File 'lib/shopify/extlib/class.rb', line 64

def cattr_writer(*syms)
  options = syms.last.is_a?(Hash) ? syms.pop : {}
  syms.flatten.each do |sym|
    class_eval(<<-RUBY, __FILE__, __LINE__ + 1)
      unless defined? @@#{sym}
        @@#{sym} = nil
      end

      def self.#{sym}=(obj)
        @@#{sym} = obj
      end
    RUBY

    unless options[:instance_writer] == false
      class_eval(<<-RUBY, __FILE__, __LINE__ + 1)
        def #{sym}=(obj)
          @@#{sym} = obj
        end
      RUBY
    end
  end
end