Re: Suggestion: Freeze and standardize public ids in Mozilla's DTD catalog

Henri Sivonen wrote:
> Considering that
> 
>  * The XML spec doesn't guarantee that an external DTD is processed, 
> which makes DTDs inherently unreliable in a system where the author 
> doesn't control the clients (like on the Web).
> 
>  * When authors do use character entities, authors need the entities to 
> work reliably--certainly not causing the YSoD.
> 
>  * Legacy pages assume the public ids in Gecko's current DTD catalog to 
> map to something that makes character entities work. This has already 
> caused grief for Opera and Safari.
> 
>  * Making browsers fetch DTDs is not feasible, so the set of DTDs that 
> "work" cannot really be dynamic.
> 
> ...I think it follows that it is bad if the availability of character 
> entities with a given DTD public id is not 100% predictable across 
> browsers and browsers versions.
> 
> The only way for the mapping to be predictable across browsers and 
> browser versions is freezing the mappings and standardizing them as a 
> grandfathered legacy, to rely on straight UTF-8 for anything that the 
> frozen mappings don't cover and to migrate to DTDless XML 1.0 over time 
> and perhaps later to XML5 if that ever goes somewhere.
> 
> I, therefore, suggest freezing the set of magic public ids Gecko knows 
> about at Firefox 3, documenting Gecko's magic pseudo-DTD catalog and 
> offering the documentation to the W3C HTML WG and WHATWG for suggested 
> inclusion as part of UA requirements for processing XHTML5.
> 
> Opinions?

This sounds like a fine idea. The only thing I'd add is that future web 
specs might increase this list. For example it would have made sense for 
the MathML and SVG specs to state that in order to implement the spec 
the UA should add a particular DTD to its DTD catalog.

/ Jonas