Joseph Wright writes:
 > On 17/09/2010 20:36, Frank Mittelbach wrote:
 > > since you already looked at the different implementations, any suggestion on
 > > how to best improve the LaTeX2e behaviour?
 > 
 > I take it that this does possibly count as a bug then, rather than as a 
 > 'feature'?

it doesn't count as a bug I would say, for the simple reason that per
specification the optional argument of \usepackage doesn't support a key value
list but just a list of option names (that themselves have no spaces)
separated by comma. Only  later packages appeared that internally added
something like keyval and manipulated the received option list from
\usepackage as a key/val list, but that happens after \usepackage has already
removed spaces and unfortunately in this case also the braces.

pragmatic approach:

 you state that one needs to say ={,}  to make things work as this is a fairly
 seldom issue

more elaborate approach

 change \@pass@ptions so that it only removes spaces up front, around a comma
 and at the end

problem with the latter is that the current definition of \@pass@ptions is at
the core of what LaTeX does, ie it is used by every package and any change in
its behaviour might result in unexpected changes somewhere.

so at the moement I'm a bit reluctant to make a change on the 2e-level for the
sake of of one very specific case unless it is fairly minimal and appears to
be "save". But I'm open to suggestions which is why I asked

frank