[Python-ideas] Python 3000 TIOBE -3%

Devin Jeanpierre jeanpierreda at gmail.com
Fri Feb 10 10:54:13 CET 2012

On Fri, Feb 10, 2012 at 4:32 AM, Tim Delaney
<timothy.c.delaney at gmail.com> wrote:
> On 10 February 2012 20:16, Dirkjan Ochtman <dirkjan at ochtman.nl> wrote:
>> open('foo').read()
>> With refcounting, the file will be closed soon. With garbage
>> collection, it won't. Being able to rely on cleanup per frame/function
>> call is pretty useful.
> This is the #1 anti-pattern that shouldn't be encouraged. Using this idiom
> is just going to cause problems (mysterious exceptions while trying to open
> files due to running out of file handles for the process) for anyone trying
> to port your code to other implementations of Python.

It's not that open('foo').read() is "good". Clearly with the presence
of nondeterministic garbage collection, it's bad. But it is convenient
and compact.

Refcounting GCs in general give very nice, predictable behavior, which
lets us ignore a lot of the details of destroying things. Without
something like this, we have to do some forms of resource management
by hand that we could otherwise push to the garbage collector, and
while sometimes this is as easy as a with statement, sometimes it
isn't. For example, what do you do if multiple objects are meant to
hold onto a file and take turns reading it? How do we close the file
at the end when all the objects are done? Is the answer "manual
refcounting"? Or is the answer "I don't care, let the GC handle it"?

-- Devin

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