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
|
# File 'lib/scout/meta_extension.rb', line 2
def self.extended(base)
meta = class << base; self; end
base.class_variable_set("@@extension_attrs", []) unless base.class_variables.include?("@@extension_attrs")
meta.define_method(:extension_attr) do |*attrs|
self.class_variable_get("@@extension_attrs").concat attrs
attrs.each do |a|
self.attr_accessor a
end
end
meta.define_method(:extended) do |obj|
attrs = self.class_variable_get("@@extension_attrs")
obj.instance_variable_set(:@extension_attrs, []) unless obj.instance_variables.include?(:@extension_attrs)
extension_attrs = obj.instance_variable_get(:@extension_attrs)
extension_attrs.concat attrs
end
meta.define_method(:setup) do |*args,&block|
if block_given?
obj, rest = block, args
else
obj, *rest = args
end
obj = block if obj.nil?
obj.extend base unless base === obj
attrs = self.class_variable_get("@@extension_attrs")
return if attrs.nil? || attrs.empty?
if rest.length == 1 && Hash === (rlast = rest.last) &&
((! (rlkey = rlast.keys.first).nil? && attrs.include?(rlkey.to_sym)) ||
(! attrs.length != 1 ))
pairs = rlast
else
pairs = attrs.zip(rest)
end
pairs.each do |name,value|
obj.instance_variable_set("@#{name}", value)
end
obj
end
base.define_method(:extension_attr_hash) do
attr_hash = {}
@extension_attrs.each do |name|
attr_hash[name] = self.instance_variable_get("@#{name}")
end
attr_hash
end
base.define_method(:annotate) do |other|
attr_values = @extension_attrs.collect do |a|
self.instance_variable_get("@#{a}")
end
base.setup(other, *attr_values)
end
base.define_method(:purge) do
new = self.dup
if new.instance_variables.include?(:@extension_attrs)
new.instance_variable_get(:@extension_attrs).each do |a|
var_name = "@#{a}".to_sym
new.remove_instance_variable(var_name) if new.instance_variables.include? var_name
end
new.remove_instance_variable("@extension_attrs")
end
new
end
end
|