Hi Joseph,

Regarding space-skipping:

On 06/08/2009, at 3:23 PM, Joseph Wright wrote:

>> Re-reading your approach in xparse-alt, I believe what is currently
>> implemented there is the best approach. It applies sensible  
>> defaults and
>> allows overrides; to whit:
>>
>> {m o}    does not skip spaces
>> {m o m}  does skip spaces
>> {m !o}   does skip spaces
>> {m ^o m} does not skip spaces
>>
>> Since (a) can't always skip spaces, and (b) never skipping spaces  
>> leads
>> to inconsistencies, and (c) only need to ignore spaces when the  
>> optional
>> argument is last -- I strongly think xparse-alt has it right.
>
> My main concern is "should we provide the option to change things"?
> Would it be clearer if the same rules always apply (is there a need to
> skip spaces to find trailing optional arguments, for example).

I would support dropping ^ and ! in xparse-alt providing that final  
optional arguments don't skip spaces.

Will