On 23/10/2009, at 6:55 AM, Joseph Wright wrote:

> This would allow things like:
> > \ReturnVariable { \MakeHarmless\ReturnVariable }
>  % Will absorb one more argument, as required
> (using \MakeHarmless from xdoc). That doesn't work at present as the  
> return has to be in a toks.
> As Lars points out, that is quite a bit more flexible at the cost of  
> a little complexity in the syntax.

I'm not sure that I see how this is any more flexible?
Oh, simply that your argument processor doesn't have to be hard-coded  
to use \l_xparse_arg_toks.
But hang on, can't you do the same thing at present by just writing

     > { \MakeHarmless\l_xparse_arg_toks }


-- Will