Victor Eijkhout <[email protected]> writes:

On Jan 2, 2014, at 10:03 AM, Jed Brown <[email protected]> wrote:

...

only for

Look, it's a demonstration prototype. The shift syntax handles one case. For other cases you need a different syntax or extend the current.

Then the proposal is for something else. The distinguishing feature of successful programming abstractions is never one of making easy things pretty. There are many ways to do that, just as there are many ways to solve a homogeneous Laplacian. A successful abstraction needs to make hard things possible. As stated earlier, my principle reservation with IMP is that adding another layer of callbacks has a long track record of being more difficult to reason about, and I'm far from convinced that it makes the model more expressive. The syntax for describing distributions is a distraction (syntax usually is), but the semantics matter. Two-sided descriptions are a usability problem, but a performance benefit. If IMP turns out not to be suitable for a particular use case, transforming from callback-driven to non-callback is a nontrivial refactoring, as is going the other direction. That's not good because it increases the overhead of incremental adoption. I find simple demonstrations as unconvincing as most patents. 99% of the work remains in extending the idea into something practical. It may or may not pan out, but we can't say anything from the simple demonstration alone.