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class HStruct | |
def self.new(*members, defaults: {}, &block) | |
invalid_defaults = defaults.keys - members | |
fail "Invalid defaults #{invalid_defaults}" if invalid_defaults.any? | |
klass = Class.new do | |
@members = members | |
@defaults = defaults | |
class << self | |
attr_reader :members, :defaults | |
end | |
attr_reader(*members) | |
def initialize(attrs = {}) | |
invalid_members = attrs.keys - self.class.members | |
fail "No members #{invalid_members} in HStruct" if invalid_members.any? | |
self.class.members.each do |key| | |
value = attrs[key] || self.class.defaults[key] | |
instance_variable_set :"@#{key}", value | |
end | |
end | |
def ==(other) | |
self.class == other.class && to_h == other.to_h | |
end | |
alias_method :eql?, :== | |
def to_h | |
self.class.members.map { |key| [key, public_send(key)] }.to_h | |
end | |
def each(&block) | |
return to_enum(__callee__) unless block_given? | |
to_h.each(&block) | |
end | |
def inspect | |
contents = self.class.members | |
.map { |key| %{#{key}="#{public_send(key).to_s.gsub('"', '\"')}"} } | |
.join(' ') | |
"#<hstruct #{self.class.name} #{contents}>" | |
end | |
end | |
klass.class_eval(&block) if block_given? | |
klass | |
end | |
end | |
# Usage | |
MyStruct = HStruct.new(:foo, :bar, :baz, :bat, defaults: { baz: 3 }) do | |
def batz | |
4 | |
end | |
end | |
data_bag = MyStruct.new(foo: 1, bar: 2) | |
data_bag.foo #=> 1 | |
data_bag.bar #=> 2 | |
data_bag.baz #=> 3 | |
data_bag.bat #=> nil | |
data_bag.batz #=> 4 |
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