[MERGE] Tweak log -n UI to support +/- as fully expanded/collapsed

[Ian Clatworthy]

Vincent Ladeuil wrote:
>>>>>> "Ian" == Ian Clatworthy <ian.clatworthy at internode.on.net> writes:
> 
>     Ian> As the most common use cases for log's new -n option are:
>     Ian> * show me all levels of nested revisions
>     Ian> * show me just the top level
> 
>     Ian> I think it's worth having the + and - symbols as aliases
>     Ian> for 0 and 1 respectively.
> 
> Can you elaborate on that ?

I think -n1 reads nicely but -n0 feels slightly strange.
I thought about -n* but adding a space (-n *) would cause
chaos in most shells. + and - are often (or were often) used
in GUI tree widgets to represent expand/collapse.

>     Ian>  def _parse_levels(s):
>     Ian> +    if s == '-':
>     Ian> +        return 1
>     Ian> +    if s == '+':
>     Ian> +        return 0
>     Ian>      try:
>     Ian>          return int(s)
>     Ian>      except ValueError:
> 
> You still don't trap negative values so I still think you'd
> better use type=int in the option declaration.

What would a negative value mean?

Also, I can't find anywhere in Bazaar that uses type=int now.
I pretty sure when I tried that months ago, it didn't work
because of how we wrap Python's OptionParser stuff with our
own enhancements. It might be fine now though.

Ian C.