In all the threads about this PEP I still haven't seen a single
example of how to write a finalizer.
Let's take a specific example of a file object (this occurs in io.py
in the p3yk branch). When a write buffer is GC'ed it must be flushed.
The current way of writing this is simple:
class BufferedWriter:
def __init__(self, raw):
self.raw = raw
self.buffer = b""
def write(self, data):
self.buffer += data
if len(self.buffer) >= 8192:
self.flush()
def flush(self):
self.raw.write(self.buffer)
self.buffer = b""
def __del__(self):
self.flush()
How would I write this without using __del__(), e.g. using weak references?
P.S. Don't bother arguing that the caller should use try/finally or
whatever. That's not the point. Assuming we have a class like this
where it has been decided that some method must be called upon
destruction, how do we arrange for that call to happen?
--
--Guido van Rossum (home page: http://www.python.org/~guido/)
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