On 27/05/2014 16:58, Bruno Le Floch wrote:
> I tend to agree with you that we should not let \__dim_strip_pt:n and
> \__dim_strip_bp:n accept arbitrary junk.  That's easy to change, as
> they are only used internally.  On the other hand, the public
> \dim_to_pt:n and \dim_to_unit:n are documented as allowing multiple
> units, for the use-case Joseph describes.

If you look over the current actual uses in the LaTeX kernel, they are
focussed purely on some aspects of font use. I suspect we'd be better,
long-term, to allow this sort of thing if at all only at the interface
layer, and to have all of the 'general' code stuff expect 'well defined'
dimensions. Means a doc change, but I feel an reasonable one.
Joseph Wright