Prorogued Proramming - somthing to consider for the D future?

[John Colvin]

On Saturday, 14 September 2013 at 19:26:04 UTC, Peter Alexander 
wrote:
> Here's a super quick summary for those without time to watch:
>
> He proposed a language keyword, 'prorogue' used like so:
>
> int foo = prorogue bar(x);
>
> The keyword indicates that, instead of calling 'bar', the code 
> should ask the user for the return value, which is then 
> memoized with the value of x, and is saved across executions. 
> bar need not be defined. You can also do things like 'return 
> prorogue;' to request a value to return.
>
> The reported uses of this are:
> - Top-down development: prorogue functions to mock them.
> - Debugging: mark a call as prorogue to provide a value to 
> repro a failure case.
> - Crowdsourcing: if you memoize across the internet then all 
> users collaborate to fill in gaps.

That's actually kindof neat. I'm not convinced by the 
Crowd-sourcing aspect, but it seems like it would be a nice 
abstraction for sketching out an architecture or debugging a 
rare, hard to access code path.

On the surface at least, this looks trivial to implement in D.