[Ur] Several patches and questions

[Adam Chlipala]

On 12/30/2012 09:09 PM, Edward Z. Yang wrote:
> One addition I noticed missing was the ability to add tags
> to the singletons list in monoize.sml:
>
>      val singletons = SS.addList (SS.empty,
>                                   ["link",
>                                    "br",
>                                    "p",
>                                    "hr",
>                                    "input",
>                                    "button",
>                                    "img"])
>
> I'm not sure what the best way of doing this would be, but maybe the emptiness
> information can be put in the type? (That way, we can also rule out<br>foo</br>, etc.)
>    

Ruling out children of tags that shouldn't have children is one thing 
which might be worth addressing, but is that the only reason to support 
registration of new singletons?  I mostly view the singletons list as 
for compatibility with browsers that don't think in terms of XML, so 
that it shouldn't be growing now that all the browsers are ready for 
XHTML.  New tags will get proper XHTML support to begin with.

We could save a few characters here and there on pages by using </> 
instead of <></>.  Is there a more compelling reason than that to make a 
change to Ur/Web?