[EMAIL PROTECTED] a écrit : (snip) > Thanks for the information. The reason why I was taking this approach > was more from a user interface perspective. What I have is a file > that contains certain geometric objects, lets call them geo. Each geo > object has 4 possible surfaces:
You mean it has one of the 4 surfaces, or it has them all ? > ps, ss, le, te. Each surface has > x,y,z coordinates. It is not known apriori if any of these surfaces > exist in the file. So I created a geo_reader class that is passed a > filename in its argument list. It then parses the file, creating a > container class for each geo object and assigning the name geo0, geo1, > geo2, etc... as an attribute of the geo_reader class. You want an indexed ordered collection (ie: something like a list) here. > The geo_reader > class also stores global attributes concerning the file, i.e. the > number of geo objects, a list handle this. > etc... Then for each geo container I bind > another container class for each surface that I find for each geo > object, i.e. the ps, ss, le, te surfaces. Then the coordinates for > each of the surfaces becomes an attribute of each of their > corresponding containers. Err... Why don't you actually take time to write the Geo and Surface classes ? It will *really* save you time in the long run. > I can also bind certain attributes to the container class to tell > whether its a geo object or surface, etc. You definitively want to write the appropriate classes. > I just didn't want the user > to have to use the dictionary syntax like this: > > x_coords = my_geo['geo0']['ps']['x'] As far as I'm concerned, I'd use a list-like interface for my_geo, ie: my_geo[0].ps.x And I'd define the four surface attributes of the Geo object, default them to either None or a NullSurface object (whose x and y attribs have the None value). > It just seems a little more natural to use the dot operator approach > for users to interface with. wrt/ attribute access, yes, indeed. wrt/ what is clearly an ordered collection, there's already a well defined interface !-) And anyway, this doesn't mean you should not properly define your classes - this is no more complex than what you're doing here, and it will make your code *way* more readable, maintainable and usable - even for your users, since they'll be able to introspect your objects type, print the docstrings (if you write them of course), eventually use autocompletion (cf the rlcompleter module) etc. > I wasn't aware of the Law of Demeter and > I agree with all your concerns. I'm just not sure which one a user > would rather interface with from the command line. The dot operators > are quicker to type. Indeed. Now if you have such concern, why not go all the way ?-) My 2 cents -- http://mail.python.org/mailman/listinfo/python-list
