Improve "Improve Contract Syntax" DIP 1009

[Mark]

On Saturday, 4 November 2017 at 06:08:22 UTC, Jonathan M Davis 
wrote:
> And even if you did have access to the input, some functions 
> consume their input without any way to save it (e.g. an input 
> range that isn't a forward range)
> 
> [...]
> 
> - Jonathan M Davis

True. I had (strongly) pure functions in my mind and I didn't 
realize that things don't work as smooth in the impure case.