Re: setupnarrower and startnarrower

[Hans Hagen <pragma@wxs.nl>]

On 8/6/2013 6:14 PM, Aditya Mahajan wrote:
> 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.

\startnarrower with its interface is one of the oldest commands which 
also means that it's used in our styles

however, we already have \startnarrow and i extended that one to accept 
a few more combinations:

\showframe

\definenarrower[whatever][left=3cm,right=2cm,default=left]

\starttext

\input ward

\startnarrower[2*left] \input ward \stopnarrower

\input ward

\startnarrow[whatever] \input ward \stopnarrow

\input ward

\startnarrow[whatever][right] \input ward \stopnarrow

\input ward

\startnarrow[whatever][default=middle] \input ward \stopnarrow

\input ward

\startnarrow[whatever][default=middle,middle=-1cm] \input ward \stopnarrow

\input ward

\startnarrow[default=middle] \input ward \stopnarrow

\input ward

\stoptext

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                                           Hans Hagen | PRAGMA ADE
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