-
Notifications
You must be signed in to change notification settings - Fork 35
/
values.rb
106 lines (86 loc) · 2.58 KB
/
values.rb
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
# Simple immutable value objects for ruby.
#
# @example Make a new value class:
# Point = Value.new(:x, :y)
#
# @example And use it:
# p = Point.new(1, 0)
# p.x
# #=> 1
# p.y
# #=> 0
#
class Value
# Create a new value class.
#
# @param [Array<Symbol>] fields Names of fields to create in the new value class
# @param [Proc] block Optionally, a block to further define the new value class
# @return [Class] A new value class with the provided `fields`
# @raise [ArgumentError] If no field names are provided
def self.new(*fields, &block)
raise ArgumentError.new('wrong number of arguments (0 for 1+)') if fields.empty?
Class.new do
attr_reader(:hash, *fields)
define_method(:initialize) do |*values|
raise ArgumentError.new("wrong number of arguments, #{values.size} for #{fields.size}") if fields.size != values.size
fields.zip(values) do |field, value|
instance_variable_set(:"@#{field}", value)
end
@hash = self.class.hash ^ values.hash
freeze
end
const_set :VALUE_ATTRS, fields
def self.with(hash)
unexpected_keys = hash.keys - self::VALUE_ATTRS
if unexpected_keys.any?
raise ArgumentError.new("Unexpected hash keys: #{unexpected_keys}")
end
missing_keys = self::VALUE_ATTRS - hash.keys
if missing_keys.any?
raise ArgumentError.new("Missing hash keys: #{missing_keys} (got keys #{hash.keys})")
end
new(*hash.values_at(*self::VALUE_ATTRS))
end
def ==(other)
eql?(other)
end
def eql?(other)
self.class == other.class && values == other.values
end
def values
self.class::VALUE_ATTRS.map { |field| send(field) }
end
def inspect
attributes = to_a.map { |field, value| "#{field}=#{value.inspect}" }.join(", ")
"#<#{self.class.name} #{attributes}>"
end
def with(hash = {})
return self if hash.empty?
self.class.with(to_h.merge(hash))
end
def to_h
Hash[to_a]
end
def recursive_to_h
Hash[to_a.map{|k, v| [k, Value.coerce_to_h(v)]}]
end
def to_a
self.class::VALUE_ATTRS.map { |field| [field, send(field)] }
end
class_eval &block if block
end
end
protected
def self.coerce_to_h(v)
case
when v.is_a?(Hash)
Hash[v.map{|hk, hv| [hk, coerce_to_h(hv)]}]
when v.respond_to?(:map)
v.map{|x| coerce_to_h(x)}
when v && v.respond_to?(:to_h)
v.to_h
else
v
end
end
end