Guido van Rossum <guido@digicool.com>:
Maybe we could add a flag to the dict that issues an error when a new key is inserted during such a for loop? (I don't think the key order can be affected when a key is *deleted*.)
You mean: mark it read-only ? That would be a "nice to have" property for a lot of mutable types indeed -- sort of like low-level locks. This would be another candidate for an object flag (much like the one Fred wants to introduce for weak referenced objects).
Yes.
For different reasons, I'd like to be able to set a constant flag on a object instance. Simple semantics: if you try to assign to a member or method, it throws an exception. Application? I have a large Python program that goes to a lot of effort to build elaborate context structures in core. It would be nice to know they can't be even inadvertently trashed without throwing an exception I can watch for. -- <a href="http://www.tuxedo.org/~esr/">Eric S. Raymond</a> No one is bound to obey an unconstitutional law and no courts are bound to enforce it. -- 16 Am. Jur. Sec. 177 late 2d, Sec 256