[jerf]

The feature that Observer would correspond to is simply Observers. Some of the patterns may happen to correspond to different names, but they don't all need different names or weird mappings, many of them are just "and now it's a feature instead of a set of classes".

That said, while the point "a design pattern is a feature missing from a language" has some validity on its own terms, the implied "and therefore a language is deficient if it has design patterns because those could be features" is nonsense. A language has some set of features. These features have an exponential combination of possibilities, and a smaller, but still exponential, set of those are useful. For every feature one lifts from "design pattern" and tries to put into the language, all that happens is an exponential number of other "features" are now closer to hand and are now "design patterns". This process does not end, and this process does not even complete enumerating all the possible useful patterns before the language has passed all human ability to understand it... or implement it.

Moreover, the argument that "all design patterns should be lifted to features" ignores the fact that features carry costs. Many kinds of costs. And those costs generally increase the cost of all the features around them. The costs become overwhelming.