[Edu-sig] Getting ready for class...

[Andre Roberge]

On 3/9/06, Gregor Lingl <glingl at aon.at> wrote:
>
>
> Andre Roberge schrieb:
> > On 3/9/06, kirby urner <kirby.urner at gmail.com> wrote:
> >
> >>Here's what I'm starting with today:
> >>
> >>http://www.4dsolutions.net/ocn/python/zoo.py
> >>
> >>Note:  inheriting from object at the top level, per André's suggestion.
> >>
> >>Kirby
> >
> >
> > I like your examples. I imagine you are presenting them to the same
> > group of students you mentioned before.  One example that I've seen on
> > comp.lang.python which I really like, especially because it has a
> > second level of inheritance, is the following (original by John
> > Gabriele, with comments modified slightly here):
> >
>
> Sorry Andre, but I really dislike this example. For me and in my lessons
>    inheritance is connected to an "isa" relation.
>
> A Monkey isa Mammal etc.
>
> This is violated here and i consider the confusion, which would be
> caused by this example, would outweigh the benefits, if any ...

Very good points.  I guess I won't be including this type of example
in the lessons I am writing for rur-ple.  Thanks!

André

>
> This doesn't work:
>
> A parent "isa" grand_parent ? - no! A child "isa" parent ? - no! I
> understand that the exmples goes about inheriting habits or opinions,
> but I really think this shouldn't be done this way
>
> Regards
>
> Gregor
>
> > #-----------------------------------------------------------------
> > class Grand_parent( object ):
> >
> >      def speak( self ):
> >          print 'Grand_parent.speak()'
> >          self.advise()
> >
> >      def advise( self ):
> >          print 'Grand_parent.advise()'
> >          self.critique()
> >
> >      def critique( self ):
> >          print 'Grand_parent.critique()'
> >
> > #-----------------------------------------------------------------
> > class Parent( Grand_parent ):
> >
> >      def speak( self ):
> >          print '\tParent.speak()'
> >          self.advise()
> >
> >      def advise( self ):
> >          print '\tParent.advise()'
> >          self.critique()
> >
> >      # The Parent inherits his criticism method from his/her own parent
> >
> > #-----------------------------------------------------------------
> > class Child( Parent ):
> >
> >      def speak( self ):
> >          print '\t\tChild.speak()'
> >          self.advise()
> >
> >      # Currently, the Child has no really useful advice to give.  The
> > child will just
> >      # parrot what he/she hears the parent say.
> >
> >      def critique( self ):
> >          print '\t\tChild.critique()'
> >
> > #-----------------------------------------------------------------
> > print 'speak() calls advise(), then advise() calls critique().'
> > print
> >
> > people = [ Grand_parent(), Parent(), Child() ]
> > for person in people:
> >      person.speak()
> >      print
> >
> > ====================
> > The output is:
> >
> > speak() calls advise(), then advise() calls critique().
> >
> > Grand_parent.speak()
> > Grand_parent.advise()
> > Grand_parent.critique()
> >
> >          Parent.speak()
> >          Parent.advise()
> > Grand_parent.critique()
> >
> >                  Child.speak()
> >          Parent.advise()
> >                  Child.critique()
> >
> > André
> > _______________________________________________
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> > Edu-sig at python.org
> > http://mail.python.org/mailman/listinfo/edu-sig
> >
> >
>
> --
> Gregor Lingl
> Reisnerstrasse 3/19
> A-1030 Wien
>
> Telefon: +43 1 713 33 98
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>
> Website: python4kids.net
>