ruby - when calling instance_eval(&lambda) to pass current context got error 'wrong number of arguments' -

to clear - code running - code proc

but if instead change proc.new lambda, i'm getting error

argumenterror: wrong number of arguments (1 0) 

may because instance_eval wants pass self param, , lambda treats method , not accept unknown params?

there 2 examples - first working:

class rule   def get_rule     proc.new { puts name }   end end  class person   attr_accessor :name    def init_rule      @name = "ruby"     instance_eval(&rule.new.get_rule)   end end 

second not:

class rule   def get_rule     lambda { puts name }   end end  class person    attr_accessor :name     def init_rule       @name = "ruby"      instance_eval(&rule.new.get_rule)    end end 

thanks

you correct in assumption. self being passed proc , lambda being instance_eval'ed. major difference between procs , lambdas lambdas check arity of block being being passed them.

so:

 class rule    def get_rule      lambda { |s| puts s.inspect; puts name; }    end  end   p = person.new  p.init_rule   #<person:0x007fd1099f53d0 @name="ruby">  ruby  

here told lambda expect block arity 1 , see in argument inspection, argument indeed self instance of person class.