ruby - shift the binding of block with args -

i'm learning ruby writing simple dsl. dsl used support event sourcing block.

class coupon     include aggregateroot      attr_reader :status      on :couponapprovedevent |event|         #want update @status of coupon instance         #but binding coupon class         @status = 'approved'      end      #other instance methods of coupon  end 

the "on" methods of coupon maps block given event, used reconstitute aggregate. defined in module aggregateroot:

module aggregateroot      attr_reader :events      def handle event         operation = self.class.event_handlers[event.class.name.to_sym]         operation.call event     end      def self.included(clazz)         clazz.class_eval             @event_handlers = {}              def self.on event_clazz, &operation                 @event_handlers[event_clazz] = operation             end              def self.event_handlers                 @event_handlers             end         end    end end 

but following test fails due block binded coupon class, therefore updates coupon class.status instead of coupon instance.status.

class coupontest < minitest::unit::testcase     def setup        @id = 1        @ar = coupon.new(@id)     end      def test_reconsititute_aggregate_root        @ar.handle(couponapprovedevent.new(@id))        assert @ar.approved?     end end 

so changed block call shift binding:

module aggregateroot      def handle event         operation = self.class.event_handlers[event.class.name.to_sym]         instance_eval(&operation)     end end 

the test passes in case, found |event| argument lost(the coupon instance passed instead).

is there way shift binding of block args?

try using code below instead of operation.call event:

instance_exec(event, &operation)