On 11/07/2013 22:13, Joseph Wright wrote:
> Looks at what seems to be needed, an ('opt-in') interface such as
> 
>   \keys_define:nn { module }
>     {
>       key-one .code:n  = { \tl_show:n { key-one } },
>       key-one .group:n = { a },
>       key-two .code:n  = { \tl_show:n { key-two } },
>     }
>   \keys_set_grouped:nnn { module } { a }
>     { key-one = value , key-two = value }
> 
> is not unreasonable. This allows each key to be in exactly one group:
> doing multiple groups is possible but more tricky. (Code follows a bit
> later.) My thinking with this is that you can simply do a 'filtered' or
> 'grouped' setting without having to track when filtering is on/off.
> 
> The above interface leaves open a few questions:
> 
>  - How is nesting handled? Does \keys_set:nn within
>    \keys_set_grouped:nnn respect groups? Does
>    \keys_set_grouped:nnn within \keys_set_grouped:nnn
>    work in a union or intersection way?
> 
>  - Do unknown keys raise an error, or are they ignored as they
>    are not in any group?

Also

 - Do unused options need to be collected/available?

-- 
Joseph Wright