> serialization too. My protocol family is both substantially simpler and better
> adapted for extensibility. For example, the generic pretty-printer (able to
> decode any message) takes ~40 lines of code.
>

I see - somehow it reminds me of stackish - kind of S expressions
backwards I guess - apparently with good performance, but also tag'ed
I reckon.

http://www.zedshaw.com/essays/stackish_xml_alternative.html

More specifically regarding DTD's:
Since I have been playing around with Ragel: http://www.complang.org/ragel/
I was also wondering about converting DTD's to state-machines with a
stack, then feed them to a Ragel input file and have Ragel produce a
table that can be run by a small interpreter.
I did something similar for an XML parser as a kind of DTD
replacement, although I manually wrote the state-machines and compiled
to C, not a table.
For OCaml you would link in the C interpreter, or rewrite it in OCaml.

Mikkel