bug#35129: Unsupported escape sequences for progress in shell

[Juri Linkov <juri@linkov.net>]

>>> Looks interesting. However, we have `progress-reporter'. The code from
>>> above shall be made available via this.
>>
>> I'm not sure if we can provide min-value/max-value for
>> make-progress-reporter.  If not, then it uses spinning/pulsing.
>> It seems progress-reporter doesn't support arbitrary strings
>> such as that come from underlying process like ^[7Progress: [ 0%]^[8
>
> progress-reporter should be improved to accept also strings like "45%"
> to be displayed literally.

Another problem is that there is no clear moment to start/stop
progress-reporter with calls to make-progress-reporter and
progress-reporter-done.

>>> This would also improve Tramp; there are requests to integrate the
>>> progress reporter from external commands.
>>
>> Could you show an example of a progress reporter from an external command.
>> Do they use arbitrary strings?
>
> Some scp or pscp versions do it. For example:
>
> $ pscp -v localhost:/net/ford/Multimedia/Eigene\ Videos/Videos/20150829_145255.mp4 /tmp/foo
> [...]
> foo                       | 203369 kB | 5810.6 kB/s | ETA: 00:00:00 | 84%

Progress on copying large files would be needed for local file operations
as well.