Since we're on that topic… in Objective-C, object layout is determined at runtime (these days anyway). It's pretty efficient though, and lets you do sometimes-u

Since we're on that topic… in Objective-C, object layout is determined at runtime (these days anyway). It's pretty efficient though, and lets you do sometimes-useful stuff like add ivars at runtime. It also kills the fragile base class binary compatibility issue that plagues other compiled languages (particularly relevant as a glue / MVC language).