>>(or (thing-at-point 'region)
>>    (thing-at-point 'url)
>>    ;; (thing-at-point 'filename)
>>    ;; (thing-at-point 'list)
>>    (thing-at-point 'symbol))
>>
>>has several problems:
>>
>>1. There is no such "thing" as 'region'.  Maybe could be added to thingatpt.el?
>>
> This was actually the most important part in the request. Maybe an extra
> optional parameter like use-region could be added to
> bounds-of-thing-at-point that uses the active region when
> region-active-p or use-region-p.

No need to add new arg, because the existing arg 'THING' can be used
to accept another value 'region'.

What I meant is just to add to thingatpt.el these 4 lines: