On 2018-09-06 16:04, Stefan Ram wrote: > "Michael F. Stemper" <michael.stem...@gmail.com> writes: >>> You have a operation »Resistance( V )«. >> Mathematically, that's an operation, I suppose. I tend to think of it >> as either a function or a method. > > I deliberately did not use neither "a function" nor > "a method" because by "operation" I meant something else, > I meant the three methods "Resistance( V )« (literally, > »Resistance( self, V )«) of your three classes (and possible > of other model classes added in the future) /viewed together > as an abstract concept/ "get the resistance under 'this' > model", independent of any specific load model.
Took me two days, but I finally grok what you said. >>> OOP is advantageous if you can anticipate that you will want >>> to extend operations for other types. >> Since the way that each operation (aside from __init__) differs >>from one load type to the next, is there really an advantage? > > The implementation differs, but not the interface and meaning. > > The advantage is that you can extend this operation for > additional types /without/ modifying the existing implementations > (the open-closed principle!). Whereas with a single > procedure in a non-OOP language, you would have to /modify/ > (error-prone!) an existing procedure. And another advantage has surfaced through this discussion. Even though the common code was only half-a-dozen lines or so, it changed three times due to suggestions made in this thread. Abstracting it to a parent meant that I only had to implement and test each of these changes in one place, rather than three. >>> (Non-OOP means in this case that you have a single >>> definition of a function »Resistance( entity, V )« which >>> contains an internal multiple branch on the type of the >>> entity.) >> To be honest, that sounds painful and hard to maintain. Of course, >> back in my F77 days, it would have been the only option. > > Well, non-OOP is /not/ obsolete. It just has other specific > advantages and disadvantages. It could be advantageous, > when one adds new operations more often than new types. To misquote "Chico Escuela", "Fortran been berry, berry good to me." -- Michael F. Stemper A preposition is something you should never end a sentence with. -- https://mail.python.org/mailman/listinfo/python-list
