[Python-Dev] strop vs. string (original) (raw)

Tim Peters tim.one@home.com
Sun, 27 May 2001 21:42:30 -0400

[MAL]

I guess there are three ways to "solve" this:

a) mutable types don't implement the getreadbuf interface

Of the few types that implement it today, that would leave only strings (8-bit and Unicode). Too much machinery just for that. Besides, I once posted an example to c.l.py showing how to use regexps to search mmap'ed files, so that must continue to work forever .

b) the getreadbuf interface is complemented with a callback interface, so the the buffer object can be notified of the change

I like this best, although there's no bound on the number of buffers that may need to be notified in case of change (i.e., the object would need to maintain a list of buffers to be notified).

c) calling getreadbuf on a mutable object causes this object to become immutable

Even easier, core dump as soon as getreadbuf is called .

[Greg Ewing]

I think it would be safe if:

1) it kept a reference to the underlying object, and

That much it already does.

2) it re-fetched the pointer and length info each time it was needed, using the underlying object's buffer interface.

If after

b = buffer(some_object)

b.getitem needed to refetch the info between

b[i]

and b[i+1]

I expect it would be so slow even Greg wouldn't want it anymore.