Ayende @ Rahien

Hi!
My name is Oren Eini
Founder of Hibernating Rhinos LTD and RavenDB.
You can reach me by phone or email:

ayende@ayende.com

+972 52-548-6969

, @ Q c

Posts: 5,969 | Comments: 44,492

filter by tags archive

What does Mixin mean?


Bill Wagner has a proposal about the usage of mixins. He is talking about having a marker interface with minimal methods (or no methods), and then extending that using extension methods. To a point, he is correct, this will give you some sense of what a mixin is. But it is not enough.  

It is not enough because of the following reasons:

  • It is not really a cohesive solution. There is no really good way to specify something like SnapshotMixin. You need interface and static class and inherit from the marker interface, etc. Those are... problematic. I want to just be able to say: "also give me the functionality of this class"
  • A more important issue is one of state. The examples in Bill's proposal are all stateless methods, but I want to have a stateful mixin. I can think of several hacks around that, but they are hacks, not a proper way to work.

Comments

Francois Tanguay

Cohesion isn't an all-or-nothing philosophy. It is something we should tend for when it applies.

I think Mixin (Tag) interfaces + Extension Methods greatly overcome any drawbacks due to less cohesion (Discoverability being one.)

State "infrastructure" required by stateful mixins should be provided by the Mixin Interface itself.

Comment preview

Comments have been closed on this topic.

FUTURE POSTS

No future posts left, oh my!

RECENT SERIES

  1. Production postmortem (5):
    29 Jul 2015 - The evil licensing code
  2. Career planning (6):
    24 Jul 2015 - The immortal choices aren't
  3. API Design (7):
    20 Jul 2015 - We’ll let the users sort it out
  4. What is new in RavenDB 3.5 (3):
    15 Jul 2015 - Exploring data in the dark
  5. The RavenDB Comic Strip (3):
    28 May 2015 - Part III – High availability & sleeping soundly
View all series

RECENT COMMENTS

Syndication

Main feed Feed Stats
Comments feed   Comments Feed Stats