RE: Differences of Implementations

["Fabio Arciniegas A." <faa@speakeasy.org>]

This addresses my question, thank you. My desire, in a nutshell,
was to hear people's opinion on adequate implementation
alternatives of Trex, specially under the light of the new
Trex-Relax alliance.
I hope to post advances on my (backtracking) C++ implementation of Trex
around the 20th.

 All the best,
 	Fabio

> > -----Original Message-----
> > From: Murata Makoto [mailto:mura034@attglobal.net]
> > Sent: Thursday, April 05, 2001 12:37 PM
> > To: trex@lists.oasis-open.org
> > Subject: Differences of Implementations
> >
> >
> > Somebody asked differences between RELAX Core V1 implementations and
> > TREX implementations.
> >
> > RELAX Core V1 has three implementations of verifiers.  One (VBRELAX)
> > is similar to PyTREX; it backtracks.  The other two implementations
> > (RELAX Verifier for C++ and RELAX Verifier for Java) are based on
> > non-deterministic bottom-up tree automata; for each element, multiple
> > states (or non-terminals or labels) are assigned.
> >
> > In my understanding, JamesC's implementation of TREX also uses
> > non-deterministic bottom-up tree automata.  However, James constructs
> > tree automata lazily.  Consequently, his implementation is extremely
> > fast when your schema is large but your instance is small.
> >
> > On the other hand, some constructs of TREX make it hard to
> > actually create tree
> > automata in advance.  I am concerned, since creation of tree automata
> > is required for type inference (note: XML Query people plan to
> > incorporate
> > type inference into their query language).  I am hoping that
> > introduction of
> > reasonable restrictions will make it possible to construct tree
> automata
> > in advance.
> >
> > Cheers,
> >
> > Makoto
> >