Interesting Thing
- Dynamic use of Object#extend at runtime invalidates the global method cache, causing performance degradations. Consider a design that makes use of extend at class parse time. Here's a slide deck that explains in detail: What Makes Ruby Go
The slide deck is deeply unconvincing.
The authors compare running a standard benchmark with and without method caching. But Object#extend doesn't turn off method caching for all time--just once for each method.
Then they call Object#extend six million times in a tight loop. If you're writing code like that, then you've got far bigger problems than method caching.
They don't actually present any real-world situation to support the impression that Object#extend should be avoided for performance reasons.
That said, the slides were very interesting, and other points they make further on do have practical applications.