[Python-Dev] PEP 246: lossless and stateless

[Clark C. Evans]

On Fri, Jan 14, 2005 at 10:02:39AM -0800, Michel Pelletier wrote:
| Phillip J. Eby wrote:
| > The result is that you generate a simple adapter class whose 
| > only state is a read-only slot pointing to the adapted object,
| > and descriptors that bind the registered implementations to that object.

it has only the functions in the interface, plus the adaptee; all
requests through the functions are forwarded on to their equivalent
in the adaptee; sounds alot like the adapter pattern ;)

| I get it!  Your last description didn't quite sink in but this one does 
| and I've been thinking about this quite a bit, and I like it.  I'm 
| starting to see how it nicely sidesteps the problems discussed in 
| the thread so far. 

I'm not sure what else this mechanism provides; besides limiting
adapters so that they cannot maintain their own state.

| Does anyone know of any other languages that take this "operational" 
| aproach to solving the substitutability problem?

Microsoft's COM?

| I also think this is easier for beginners to understand, instead of 
| "you have to implement this interface, look at it over here, 
| that's the "file" interface, now you implement that in your object
| and you better do it all right" you just tell them "call your 
| method 'read' and say its 'like file.read' and your thing will work 
| where any file can be read.

A tangable example would perhaps better explain... 

Looking forward to the PEP,

Clark