Prorogued Proramming - somthing to consider for the D future?

[Peter Alexander]

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.