1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
|
require 'active_support/core_ext/array/extract_options'
# Extends the module object with class/module and instance accessors for
# class/module attributes, just like the native attr* accessors for instance
# attributes.
class Module
# Defines a class attribute and creates a class and instance reader methods.
# The underlying the class variable is set to +nil+, if it is not previously
# defined.
#
# module HairColors
# mattr_reader :hair_colors
# end
#
# HairColors.hair_colors # => nil
# HairColors.class_variable_set("@@hair_colors", [:brown, :black])
# HairColors.hair_colors # => [:brown, :black]
#
# The attribute name must be a valid method name in Ruby.
#
# module Foo
# mattr_reader :"1_Badname "
# end
# # => NameError: invalid attribute name
#
# If you want to opt out the creation on the instance reader method, pass
# <tt>instance_reader: false</tt> or <tt>instance_accessor: false</tt>.
#
# module HairColors
# mattr_writer :hair_colors, instance_reader: false
# end
#
# class Person
# include HairColors
# end
#
# Person.new.hair_colors # => NoMethodError
#
#
# Also, you can pass a block to set up the attribute with a default value.
#
# module HairColors
# cattr_reader :hair_colors do
# [:brown, :black, :blonde, :red]
# end
# end
#
# class Person
# include HairColors
# end
#
# Person.hair_colors # => [:brown, :black, :blonde, :red]
def mattr_reader(*syms)
options = syms.extract_options!
syms.each do |sym|
raise NameError.new("invalid attribute name: #{sym}") unless sym =~ /^[_A-Za-z]\w*$/
class_eval(<<-EOS, __FILE__, __LINE__ + 1)
@@#{sym} = nil unless defined? @@#{sym}
def self.#{sym}
@@#{sym}
end
EOS
unless options[:instance_reader] == false || options[:instance_accessor] == false
class_eval(<<-EOS, __FILE__, __LINE__ + 1)
def #{sym}
@@#{sym}
end
EOS
end
class_variable_set("@@#{sym}", yield) if block_given?
end
end
alias :cattr_reader :mattr_reader
# Defines a class attribute and creates a class and instance writer methods to
# allow assignment to the attribute.
#
# module HairColors
# mattr_writer :hair_colors
# end
#
# class Person
# include HairColors
# end
#
# HairColors.hair_colors = [:brown, :black]
# Person.class_variable_get("@@hair_colors") # => [:brown, :black]
# Person.new.hair_colors = [:blonde, :red]
# HairColors.class_variable_get("@@hair_colors") # => [:blonde, :red]
#
# If you want to opt out the instance writer method, pass
# <tt>instance_writer: false</tt> or <tt>instance_accessor: false</tt>.
#
# module HairColors
# mattr_writer :hair_colors, instance_writer: false
# end
#
# class Person
# include HairColors
# end
#
# Person.new.hair_colors = [:blonde, :red] # => NoMethodError
#
# Also, you can pass a block to set up the attribute with a default value.
#
# class HairColors
# mattr_writer :hair_colors do
# [:brown, :black, :blonde, :red]
# end
# end
#
# class Person
# include HairColors
# end
#
# Person.class_variable_get("@@hair_colors") # => [:brown, :black, :blonde, :red]
def mattr_writer(*syms)
options = syms.extract_options!
syms.each do |sym|
raise NameError.new("invalid attribute name: #{sym}") unless sym =~ /^[_A-Za-z]\w*$/
class_eval(<<-EOS, __FILE__, __LINE__ + 1)
@@#{sym} = nil unless defined? @@#{sym}
def self.#{sym}=(obj)
@@#{sym} = obj
end
EOS
unless options[:instance_writer] == false || options[:instance_accessor] == false
class_eval(<<-EOS, __FILE__, __LINE__ + 1)
def #{sym}=(obj)
@@#{sym} = obj
end
EOS
end
send("#{sym}=", yield) if block_given?
end
end
alias :cattr_writer :mattr_writer
# Defines both class and instance accessors for class attributes.
#
# module HairColors
# mattr_accessor :hair_colors
# end
#
# class Person
# include HairColors
# end
#
# Person.hair_colors = [:brown, :black, :blonde, :red]
# Person.hair_colors # => [:brown, :black, :blonde, :red]
# Person.new.hair_colors # => [:brown, :black, :blonde, :red]
#
# If a subclass changes the value then that would also change the value for
# parent class. Similarly if parent class changes the value then that would
# change the value of subclasses too.
#
# class Male < Person
# end
#
# Male.hair_colors << :blue
# Person.hair_colors # => [:brown, :black, :blonde, :red, :blue]
#
# To opt out of the instance writer method, pass <tt>instance_writer: false</tt>.
# To opt out of the instance reader method, pass <tt>instance_reader: false</tt>.
#
# module HairColors
# mattr_accessor :hair_colors, instance_writer: false, instance_reader: false
# end
#
# class Person
# include HairColors
# end
#
# Person.new.hair_colors = [:brown] # => NoMethodError
# Person.new.hair_colors # => NoMethodError
#
# Or pass <tt>instance_accessor: false</tt>, to opt out both instance methods.
#
# module HairColors
# mattr_accessor :hair_colors, instance_accessor: false
# end
#
# class Person
# include HairColors
# end
#
# Person.new.hair_colors = [:brown] # => NoMethodError
# Person.new.hair_colors # => NoMethodError
#
# Also you can pass a block to set up the attribute with a default value.
#
# module HairColors
# mattr_accessor :hair_colors do
# [:brown, :black, :blonde, :red]
# end
# end
#
# class Person
# include HairColors
# end
#
# Person.class_variable_get("@@hair_colors") #=> [:brown, :black, :blonde, :red]
def mattr_accessor(*syms, &blk)
mattr_reader(*syms, &blk)
mattr_writer(*syms, &blk)
end
alias :cattr_accessor :mattr_accessor
end
|
