diff options
Diffstat (limited to 'activesupport/lib/active_support/core_ext/module/delegation.rb')
| -rw-r--r-- | activesupport/lib/active_support/core_ext/module/delegation.rb | 52 |
1 files changed, 25 insertions, 27 deletions
diff --git a/activesupport/lib/active_support/core_ext/module/delegation.rb b/activesupport/lib/active_support/core_ext/module/delegation.rb index 58146cdf7a..24df83800b 100644 --- a/activesupport/lib/active_support/core_ext/module/delegation.rb +++ b/activesupport/lib/active_support/core_ext/module/delegation.rb @@ -1,15 +1,23 @@ +require 'set' + class Module # Error generated by +delegate+ when a method is called on +nil+ and +allow_nil+ # option is not used. class DelegationError < NoMethodError; end + RUBY_RESERVED_WORDS = Set.new( + %w(alias and BEGIN begin break case class def defined? do else elsif END + end ensure false for if in module next nil not or redo rescue retry + return self super then true undef unless until when while yield) + ).freeze + # Provides a +delegate+ class method to easily expose contained objects' # public methods as your own. # # ==== Options # * <tt>:to</tt> - Specifies the target object # * <tt>:prefix</tt> - Prefixes the new method with the target name or a custom prefix - # * <tt>:allow_nil</tt> - if set to true, prevents a +NoMethodError+ to be raised + # * <tt>:allow_nil</tt> - if set to true, prevents a +NoMethodError+ from being raised # # The macro receives one or more method names (specified as symbols or # strings) and the name of the target object via the <tt>:to</tt> option @@ -163,45 +171,35 @@ class Module line = line.to_i to = to.to_s - to = 'self.class' if to == 'class' + to = "self.#{to}" if RUBY_RESERVED_WORDS.include?(to) methods.each do |method| # Attribute writer methods only accept one argument. Makes sure []= # methods still accept two arguments. definition = (method =~ /[^\]]=$/) ? 'arg' : '*args, &block' - # The following generated methods call the target exactly once, storing + # The following generated method calls the target exactly once, storing # the returned value in a dummy variable. # # Reason is twofold: On one hand doing less calls is in general better. # On the other hand it could be that the target has side-effects, # whereas conceptually, from the user point of view, the delegator should # be doing one call. - if allow_nil - module_eval(<<-EOS, file, line - 3) - def #{method_prefix}#{method}(#{definition}) # def customer_name(*args, &block) - _ = #{to} # _ = client - if !_.nil? || nil.respond_to?(:#{method}) # if !_.nil? || nil.respond_to?(:name) - _.#{method}(#{definition}) # _.name(*args, &block) - end # end - end # end - EOS - else - exception = %(raise DelegationError, "#{self}##{method_prefix}#{method} delegated to #{to}.#{method}, but #{to} is nil: \#{self.inspect}") - module_eval(<<-EOS, file, line - 2) - def #{method_prefix}#{method}(#{definition}) # def customer_name(*args, &block) - _ = #{to} # _ = client - _.#{method}(#{definition}) # _.name(*args, &block) - rescue NoMethodError => e # rescue NoMethodError => e - if _.nil? && e.name == :#{method} # if _.nil? && e.name == :name - #{exception} # # add helpful message to the exception - else # else - raise # raise - end # end - end # end - EOS - end + exception = %(raise DelegationError, "#{self}##{method_prefix}#{method} delegated to #{to}.#{method}, but #{to} is nil: \#{self.inspect}") + + method_def = [ + "def #{method_prefix}#{method}(#{definition})", + " _ = #{to}", + " if !_.nil? || nil.respond_to?(:#{method})", + " _.#{method}(#{definition})", + " else", + " #{exception unless allow_nil}", + " end", + "end" + ].join ';' + + module_eval(method_def, file, line) end end end |