[patch] delete a range of display numbers

[Michael Snyder]

Pedro Alves wrote:
> The "delete" breakpoint command accepts ranges as
> well, and even has code that handles convenience
> variables mixed with the numbers.  I think we should
> reuse that instead of re-adding code that parses ranges.
> Might as well make the "delete display" command
> implementation look more like the "delete" command
> implementation.  Here's a quick cut at it.
> 

Yes, I was wishing that that code were reuseable, so that I could
use it for info threads.