Class Class
In: lib/extlib/class.rb
Parent: Object
Class dot/f_15.png

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.

Methods

Public Instance methods

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

@param *syms<Array[*to_s, Hash{:instance_writer => Boolean}]> Array of attributes to define accessor for. @option syms :instance_writer<Boolean> if true, instance-level attribute writer is defined. @return <Array[to_s]> List of attributes that were made into accessors

@api public

[Source]

     # File lib/extlib/class.rb, line 97
 97:   def cattr_accessor(*syms)
 98:     cattr_reader(*syms)
 99:     cattr_writer(*syms)
100:   end

Defines class-level and instance-level attribute reader.

@param *syms<Array> Array of attributes to define reader for. @return <Array[to_s]> List of attributes that were made into cattr_readers

@api public

@todo Is this inconsistent in that it does not allow you to prevent

  an instance_reader via :instance_reader => false

[Source]

    # File lib/extlib/class.rb, line 38
38:   def cattr_reader(*syms)
39:     syms.flatten.each do |sym|
40:       next if sym.is_a?(Hash)
41:       class_eval("unless defined? @@\#{sym}\n@@\#{sym} = nil\nend\n\ndef self.\#{sym}\n@@\#{sym}\nend\n\ndef \#{sym}\n@@\#{sym}\nend\n", __FILE__, __LINE__ + 1)
42:     end
43:   end

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

@param <Array[*to_s, Hash{:instance_writer => Boolean}]> Array of attributes to define writer for. @option syms :instance_writer<Boolean> if true, instance-level attribute writer is defined. @return <Array[to_s]> List of attributes that were made into cattr_writers

@api public

[Source]

    # File lib/extlib/class.rb, line 65
65:   def cattr_writer(*syms)
66:     options = syms.last.is_a?(Hash) ? syms.pop : {}
67:     syms.flatten.each do |sym|
68:       class_eval("unless defined? @@\#{sym}\n@@\#{sym} = nil\nend\n\ndef self.\#{sym}=(obj)\n@@\#{sym} = obj\nend\n", __FILE__, __LINE__ + 1)
69: 
70:       unless options[:instance_writer] == false
71:         class_eval("def \#{sym}=(obj)\n@@\#{sym} = obj\nend\n", __FILE__, __LINE__ + 1)
72:       end
73:     end
74:   end

Defines class-level inheritable attribute accessor. Attributes are available to subclasses, each subclass has a copy of parent‘s attribute.

@param *syms<Array[*to_s, Hash{:instance_writer => Boolean}]> Array of attributes to

  define inheritable accessor for.

@option syms :instance_writer<Boolean> if true, instance-level inheritable attribute writer is defined. @return <Array[to_s]> An Array of attributes turned into inheritable accessors.

@api public

[Source]

     # File lib/extlib/class.rb, line 180
180:   def class_inheritable_accessor(*syms)
181:     class_inheritable_reader(*syms)
182:     class_inheritable_writer(*syms)
183:   end

Defines class-level inheritable attribute reader. Attributes are available to subclasses, each subclass has a copy of parent‘s attribute.

@param *syms<Array[to_s]> Array of attributes to define inheritable reader for. @return <Array[to_s]> Array of attributes converted into inheritable_readers.

@api public

@todo Do we want to block instance_reader via :instance_reader => false @todo It would be preferable that we do something with a Hash passed in

  (error out or do the same as other methods above) instead of silently
  moving on). In particular, this makes the return value of this function
  less useful.

[Source]

     # File lib/extlib/class.rb, line 115
115:   def class_inheritable_reader(*ivars)
116:     instance_reader = ivars.pop[:reader] if ivars.last.is_a?(Hash)
117: 
118:     ivars.each do |ivar|
119:       self.class_eval "def self.\#{ivar}\nreturn @\#{ivar} if defined?(@\#{ivar})\nreturn nil      if self.object_id == \#{self.object_id}\nivar = superclass.\#{ivar}\nreturn nil if ivar.nil?\n@\#{ivar} = ivar.try_dup\nend\n", __FILE__, __LINE__ + 1
120: 
121:       unless instance_reader == false
122:         self.class_eval "def \#{ivar}\nself.class.\#{ivar}\nend\n", __FILE__, __LINE__ + 1
123:       end
124:     end
125:   end

Defines class-level inheritable attribute writer. Attributes are available to subclasses, each subclass has a copy of parent‘s attribute.

@param *syms<Array[*to_s, Hash{:instance_writer => Boolean}]> Array of attributes to

  define inheritable writer for.

@option syms :instance_writer<Boolean> if true, instance-level inheritable attribute writer is defined. @return <Array[to_s]> An Array of the attributes that were made into inheritable writers.

@api public

@todo We need a style for class_eval <<-HEREDOC. I‘d like to make it

  class_eval(<<-RUBY, __FILE__, __LINE__), but we should codify it somewhere.

[Source]

     # File lib/extlib/class.rb, line 153
153:   def class_inheritable_writer(*ivars)
154:     instance_writer = ivars.pop[:instance_writer] if ivars.last.is_a?(Hash)
155:     ivars.each do |ivar|
156:       self.class_eval "def self.\#{ivar}=(obj)\n@\#{ivar} = obj\nend\n", __FILE__, __LINE__ + 1
157:       unless instance_writer == false
158:         self.class_eval "def \#{ivar}=(obj) self.class.\#{ivar} = obj end\n", __FILE__, __LINE__ + 1
159:       end
160:     end
161:   end

[Validate]