On 27 Nov, 06:20, John O'Hagan <[EMAIL PROTECTED]> wrote: > Apologies if this is a D.Q., I'm still learning to use classes, and this > little problem has proved too specific to find in the tutorials. > > I have two classes with a relationship that I find confusing. > > One is called Engine, and it has a method (bar_builder) which generates > instances of the other class, called Bar (not as in Foo but as in bar of > music; inherits from list). > > Also, Bar takes the generating instance of Engine as an argument to its > __init__ method: > > class Bar(list): > > def __init__(self, a_bar, args, engine): > list.__init__ (self, a_bar) > self[:] = a_bar > self.args = args > self.engine = engine > #more instance attributes... > > #methods... > > class Engine: > > def __init__(self, args): > self.args = args > #more instance attributes... > > def bar_builder(self): > #body of method generates lists... > yield Bar([generated_list], args, self) > > #more methods... > > #(other stuff...) > > def main(args): > > engine = Engine(args) > bars = engine.bar_builder() > for a_bar in bars: > #play the music!... > > While this works (to my surprise!) and solves the problem which motivated it > (i.e. Engine instances need to pass some attributes to Bar instances ), it > seems too convoluted. Should one class inherit the other? If so, which way > around? Or is it fine as is? > > I'm hoping this is a common trap I've fallen into; I just haven't been able to > get my head around it. (I'm a musician...) > > John O'Hagan
if you need the engine to generate a (potentially) infinite sequence of bars, this approach seems the most linear you could do ... Inheritance is for classes which share attribute/methods, which is not the case ... then, there are always many way to to the same thing, and sometime they are equivalent but for the programmer taste ... Ciao ------ FB -- http://mail.python.org/mailman/listinfo/python-list
