in reply to
Re^2: How A Function Becomes Higher Order
in thread How A Function Becomes Higher Order
O.k., you're talking about extending the one function in situ, not the kind of extension that subclassing or aggregation gives.
And that's essentially my complaint about this technique: it's nearly impossible to build large, extensible frameworks with. In my experience, functional programming works great at small levels of granularity; for anything larger, OO is far more useful. (Of course, the FP purists will disagree, and I'm not saying they're wrong.)