Re: [gentoo-portage-dev] [PATCH] unprivileged mode: generate PORTAGE_DEPCACHEDIR

[Zac Medico <zmedico@gentoo.org>]

On 11/10/2014 12:32 PM, Alexander Berntsen wrote:
> On 10/11/14 19:21, Zac Medico wrote:
>> Well, you'll have to clarify what's so "terrible" about it. Note that I didn't
>> use os.path.isdir or similar because those functions hide all kinds of relevant
>> exceptions, such as EACCES.
> I wish there were a more declarative way of expressing this in Python.
> It's extremely imperative.

We could certainly express it in a way that doesn't involve any mutating
loop control variables, but ultimately that's going to lead to more
lines of code, and it will leave imperative programmers wondering why we
didn't choose a simpler and more succinct approach.

For example, we could create an class for iterating over the paths from
a given path down to the root directory. Then we could create a function
which selects the first element from that iterator that exists. Once the
class and function are implemented, their usage would be very succinct:

  first_parent = first_existing(iter_parents(path))
-- 
Thanks,
Zac