def fattrs(*args, &block)
unless args.empty?
returned = Hash.new
args.flatten!
args.compact!
all_hashes = args.all?{|arg| Hash===arg}
names_and_configs = {}
if all_hashes
args.each do |hash|
hash.each do |key, val|
name = key.to_s
config = Hash===val ? val : {:default => val}
names_and_configs[name] = config
end
end
else
config = Hash===args.last ? args.pop : {}
names = args.select{|arg| Symbol===arg or String===arg}.map{|arg| arg.to_s}
names.each do |name|
names_and_configs[name] = config
end
end
initializers = __fattrs__.initializers
names_and_configs.each do |name, config|
raise(NameError, "bad instance variable name '@#{ name }'") if("@#{ name }" =~ %r/[!?=]$/o)
name = name.to_s
default = nil
default = config[:default] if config.has_key?(:default)
default = config['default'] if config.has_key?('default')
inheritable = false
if Module===self
inheritable = config[:inheritable] if config.has_key?(:inheritable)
inheritable = config['inheritable'] if config.has_key?('inheritable')
end
initialize = (
if inheritable
lambda do |*ignored|
parents = ancestors[1..-1]
catch(:value) do
parents.each do |parent|
throw(:value, parent.send(name)) if parent.respond_to?(name)
end
block ? block.call : default
end
end
else
block || lambda{|*ignored| default }
end
)
initializer = lambda do |this|
Object.instance_method('instance_eval').bind(this).call(&initialize)
end
initializer_id = initializer.object_id
__fattrs__.initializers[name] = initializer
compile = lambda do |code|
begin
module_eval(code)
rescue SyntaxError
raise(SyntaxError, "\n#{ code }\n")
end
end
code = "def \#{ name }=(*value, &block)\nvalue.unshift block if block\n@\#{ name } = value.first\nend\n"
compile[code]
code = "def \#{ name }(*value, &block)\nvalue.unshift block if block\nreturn self.send('\#{ name }=', value.first) unless value.empty?\n\#{ name }! unless defined? @\#{ name }\n@\#{ name }\nend\n"
compile[code]
??
module_eval do
define_method "#{ name }!""#{ name }!" do
self.send "#{ name }=""#{ name }=", initializer.call(self)
self.instance_variable_get "@#{name}""@#{name}"
end
end
code = "def \#{ name }?\nself.\#{ name }\nend\n"
compile[code]
fattrs << name
returned[name] = initializer
end
returned
else
begin
__fattr_list__
rescue NameError
singleton_class =
class << self
self
end
klass = self
singleton_class.module_eval do
fattr_list = List.new
define_method('fattr_list'){ klass == self ? fattr_list : raise(NameError) }
alias_method '__fattr_list__', 'fattr_list'
end
__fattr_list__
end
end
end