On Tue, 6 Aug 2013, Wolfgang Schuster wrote:

>
> Am 06.08.2013 um 17:53 schrieb Aditya Mahajan <adityam@umich.edu>:
>
>> On Tue, 6 Aug 2013, Wolfgang Schuster wrote:
>>
>>>
>>> Am 06.08.2013 um 16:09 schrieb Alan BRASLAU <alan.braslau@cea.fr>:
>>>
>>>> Thank you Wolfgang, but I was wondering about the standard \startnarrower.
>>>>
>>>> Many (some) commands allow setup assignments, the use of which overides but does not change the default. This is a very useful feature of ConTeXt that suggest could be generalized. \startnarrower is but one example.
>>>
>>> Changing the command is simple but I would drop the second
>>> argument when you want to change the left/right etc. values
>>> because you can say “left=4cm” etc. to get the desired margins.
>>
>> startnarrower has a weird interface. Ideally, it should just support keywords:
>>
>> \startnarrower
>>    [
>>      leftmargin=...,
>>      rightmargin=...,
>>      alternative=(left|right|both),
>>      spacebefore=....,
>>      spaceafter=....,
>>      indenting=....,
>>      indentnext=....,
>>      before=....,
>>      after=....,
>>    ]
>
> That’s more or less what I use for the “narrow” alternative in the annotation module.
>
> I would prefer such a parameter driven narrower environment myself (do we even need
> the left, middle and right option when we can set absolute margins) but keeping the current
> interface for backwards compatibility make things a little bit ugly.

Haven't we broken backward compatibility for other environments as well? 
\startlinenumbering immediately comes to mind where the MkII interface was

    \startlinenumbering[continue]

and the current interface is

    \startlinenumbering[continue=yes]

I, for one, think that it is OK to break backward compatibility for more 
elegance and consistency.

Aditya