marrying bundle and directive? (Re: [MERGE] Merge directive format 2, Bundle format 4)

[Martin Pool]

>     >> bzr emit [SUBMIT_BRANCH  [PUBLIC_BRANCH]]
>
>     aaron> The way I wrote it is the way bzr writes it.  (See bzr
>     aaron> help checkout, for example.)
>
> I understand.
>
>     aaron> I think it's important for you to be able to decode
>     aaron> that.
>
> I do. I just feel a bit disturbed each time ;-)
>
>     aaron> Personally, I find the second form less pleasing,
>
> I agree it's less pleasing, may be I wrote too many parsers that
> blew up in my face on such ambiguities, but we use a scanner
> (optparse) to analyze the options and I don't think it will be
> easy to take that into account. Even if this second form
> describes what we will really accept or not: 'bzr emit
> PUBLIC_BRANCH' is illegal.

The parser knows how it works, but humans may find it ambiguous: are
they filled from left to right, or according to some kind of best-fit,
or something else?  For this reason I think we should change to the
nested brackets.

-- 
Martin