Ruby: Mildly 'exotic' inheritance doesn't work? -

i factor bunch of common code subclasses superclass method. superclass method must refer nonexistent (in superclass) method defined in subclasses. can't work.

this 1 try out of many multiple variations have tried:

class superclass     def chunk_of_code         # <code...>         nonexistant_superclass_method_defined_in_subclass params         # <more code...>     end end  class subclass < superclass     def nonexistant_superclass_method_defined_in_subclass params         # whatever...     end end  subclass.new.chunk_of_code params 

this doesn't work. other variations don't work either. kind of coding possible in ruby (i thought was)? did kind of thing time working in smalltalk.

any way achieve want? please avoid advising me use "mix-ins" or "modules," i'd just learn , use ruby's inheritance right now.

*running latest version of ruby.

thanks.

edit: in rails app. superclass applicationcontroller.

edit: here actual code 1 of many iterations i've tried this. particular example craps out "undefined method `each' nil:nilclass" in view, apparently because whole thing running in context of super (where isn't defined) instead of sub, or @ least that's interpretation:

class applicationcontroller < actioncontroller::base     protect_from_forgery     before_filter :authenticate_registration!      # models , x defined in subclass     def index         models = x.where registration_id: current_registration.id          respond_to |format|             format.html # index.html.erb             format.json { render json: models }         end     end     # more code here...     # ... end  class positionscontroller < applicationcontroller     def x         position     end      def models= blah         @positions = blah     end      # more code here...     # ... end 

your error nothing inheritance , on line

models = x.where registration_id: current_registration.id 

this potentially ambiguous: mean call method models= or mean assign local variable called models? in (and similar) situation ruby assumes you're trying deal local variable. if want call method instead need do

self.models = x.where registration_id: current_registration.id 

since models= method doesn't called, @positions nil , assume view tries use it.

you might interested in gems such make_resourceful handle common controller stuff.