Short Screencasts of Gourmet Ruby, by Avdi Grimm
DRY stands for “Don’t Repeat Yourself“.
As originally put forth in the book The Pragmatic Programmer, the DRY principle says that
Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
This principle is also known as “Once and Only Once“, or OAOO.
In this episode, guest chef Sam Livingston-Gray shows us how getting a new view on our data model can drive out a cleaner design.
In today's episode, we look at a new example of coincidental duplication: code that appears to be repeated, but really represents different pieces of knowledge.
We've used the "ghost object" pattern to lazily load attributes of a model object. And we've made a macro to easily declare "ghost-loadable" attribute accessors. Today we complete the generalization …
When is it appropriate to metaprogram? Today's episode looks at one situation in which it may be a good choice.
Katrina Owen contributed an example of coincidental duplication I liked so much I decided to make a second episode about it. Enjoy!
The DRY principle teaches us to get rid of duplication wherever we find it. But not all duplication is created equal...
