Comments on Just a little Python: Lazy Descriptors

It looks like these days this pattern is available...

2010-10-01T09:25:45.691-04:00

It looks like these days this pattern is available in zope.cachedescriptors (which can be installed from pypi independently of zope) as property.Lazy: http://pypi.python.org/pypi/zope.cachedescriptors#lazy-computed-attributes

interesting take nice solution

2010-09-13T20:16:11.537-04:00

interesting take nice solution

Rick I just ran across this post by accident. Thi...

2010-02-02T00:45:54.150-05:00

Rick I just ran across this post by accident. This is indeed an elegant pattern. Thanks for posting.

thumbs up! a very elegant pattern.

2009-12-07T04:46:00.916-05:00

thumbs up! a very elegant pattern.

ahhh.. it used my very very old profile to post my...

2009-02-13T07:18:00.000-05:00

ahhh.. it used my very very old profile to post my comment.... grrrr

drop me a comment in livingubuntu.com or an email to alfredodeza (at) gmail.com

rick, I watched your presentation last night but h...

2009-02-13T07:16:00.000-05:00

rick, I watched your presentation last night but had to leave early.

Would love to offer my help with Clutch.

Let me know what can I do to help out.

I'm really excited to use this. Maybe sometime thi...

2008-08-24T20:27:00.000-04:00

I'm really excited to use this. Maybe sometime this week in Algebra or Geometry class. ;)

@ronny:

Thanks for the pointers. I have up...

2008-08-24T14:16:00.000-04:00

@ronny:

Thanks for the pointers. I have updated the post to reflect your changes.

@anonymous:
With the changes suggested by ronny, a function is no longer called on each attribute access (technically, it wasn't being called before, I just had an extraneous check of the object's __dict__).

you don't need to check if the attribute slot is o...

2008-08-24T11:39:00.000-04:00

you don't need to check if the attribute slot is on the instance

non-data descriptors get overridden by instance attributes

also please copy the name to __name__ and the documentation to __doc__

so its more easy to use with the common introspection tools

@doug:
Yup, you guessed it. In particular, I w...

2008-08-23T10:05:00.000-04:00

@doug:
Yup, you guessed it. In particular, I wanted an ORM-mapped object as an attribute on a TurboGears controller.

@anonymous:
Actually, I didn't invent the name ...

2008-08-23T10:03:00.000-04:00

@anonymous:
Actually, I didn't invent the name "descriptor" -- it's Python terminology documented here. I probably should have given more context in the post. As for a function being called every time, yes, that still happens, but the (potentially expensive) calculation of the value of bar only happens once.

That looks like a good way to defer object retriev...

2008-08-23T07:52:00.000-04:00

That looks like a good way to defer object retrieval from a database.

Mate,

Great post. I wish you had posted...

2008-08-23T07:37:00.000-04:00

Mate,

Great post. I wish you had posted this a month earlier :D. I had stumbled upon this in django (in the django.contrib.auth.middleware.py). It does just the thing to obtain access to the user object on a request.

But keep em coming mate, keep em coming.

Cheers
Sri

I'm too lazy to try to understand how this thing w...

2008-08-23T06:28:00.000-04:00

I'm too lazy to try to understand how this thing works, what it does, and ramifications... but your naming it "descriptor", uh, woot?

http://foldoc.org/foldoc.cgi?query=descriptor

And isn't a function called _every_ time anyway?

Comments on Just a little Python: Lazy Descriptors

It looks like these days this pattern is available...

interesting take nice solution

Rick I just ran across this post by accident. Thi...

thumbs up! a very elegant pattern.

ahhh.. it used my very very old profile to post my...

rick, I watched your presentation last night but h...

I'm really excited to use this. Maybe sometime thi...

@ronny:Thanks for the pointers. I have up...

you don't need to check if the attribute slot is o...

@doug:Yup, you guessed it. In particular, I w...

@anonymous:Actually, I didn't invent the name ...

That looks like a good way to defer object retriev...

Mate, Great post. I wish you had posted...

I'm too lazy to try to understand how this thing w...

@ronny:

Thanks for the pointers. I have up...

@doug:
Yup, you guessed it. In particular, I w...

@anonymous:
Actually, I didn't invent the name ...

Mate,

Great post. I wish you had posted...