Re: Multiton in standard library

On Mar 16, 2007, at 12:06 PM, TRANS wrote:
> Well it's not your most common pattern, clearly.

Actually, I think it's probably fairly common.  As you agreed, it's  
the standard technique for implementing an immutable object.  I've  
certainly seen it used in Java and Python programming. (I've just  
never run across this name for it before seeing your module.)

> And I have
> seen it called the Immutable pattern too. But for the module it
> doesn't make as much sense b/c the Multiton is not the only way to
> achieve Immutability. The Singleton Pattern [is] an Immutable too.

Singletons aren't immutable at all.  Singleton's have modifiable  
state; Immutables can't.  I guess the right way to look at it is that  
Immutable and Singleton are distinct subtypes of Multiton.  And,  
therefore, you're right that Immutable wouldn't be an appropriate  
name for your mixin, since these objects could still have modifiable  
state, just not with respect to their constructor arguments.

Tom