Re: [xml-dev] Parser structure (historical background question)

[Gavin Thomas Nicol <gtn@rbii.com>]

On Wednesday 21 November 2001 03:00 pm, Dennis Sosnoski wrote:
> I'm curious how it came about that (at least for SAX) validation was
> incorporated into the parser. It'd seem to make a lot more sense to have
> it as a separate layer that works off a parse event stream. This type of
> approach would vastly increase the flexibility (allowing validation to
> be just another pipeline step) without substantially adding to the
> costs, as far as I can see.
>
> Any comments?

Historically, SGML *required* validation of the parser, so many of the early 
discussions around validation assumed this. I forget who first noted that 
validation is orthoganal to parsing, but I know I was an early proponent
of "lazy validation". Tim Bray's Lark/Larva good example of a pipeline 
approach to this.

I have no idea why later parsers added early validation. It still seems like
a bad idea to me...