Re: [boost] Probing interest in a typed XML traversal library

Subject: Re: [boost] Probing interest in a typed XML traversal library
From: Sumant Tambe (sutambe_at_[hidden])
Date: 2010-12-02 12:31:40

Hi Mateusz and Klaim,

Your library seems interesting (I'm not an expert at all here but I like the
> idea).
>
> However the examples are far from being obvious about this librarie's use.
> Maybe some kind of "hello world" or simple FULL example might help?
> A simple heavily commented program doing some simple manipulations using a
> given test xml file and an xsd file might be a good idea.
>

There are several complete examples available in the source repository. Here
is a link to the library example.
https://svn.dre.vanderbilt.edu/viewvc/LEESA/trunk/LEESA/tests/library-xsd/

Please see driver.cxx in the directory. I would not say it is documented
well, but there are #ifdefs WITH_LEESA and WITHOUT_LEESA that clearly show
differences between two approaches. WITHOUT_LEESA being just the API
generated by xml data binding tool. These are the same tests I used to get
the run-time and compile-time performance numbers below. I've attached an
image with two graphs which can also be found in one of the papers on LEESA.

http://www.dre.vanderbilt.edu/~sutambe/documents/pubs/LEESA-Multiparadigm.pdf

With respect to validating/non-validating XML parsers, LEESA is always a
validating library but the key difference
is that it does not validate the input XML (which can only be done at
runtime). It validates your queries at compile-time.
The programming model is vastly different due to its focus on types and
compile-time validation. LEESA always needs a
xml data binding tool that generates C++ classes from an xsd. If the xml
data binding tool is validating xml at
run-time, then your input xml and queries are both validated! Remember that
the queries are XPath-like. Many features
of XPath are not supported. But that is not the goal here. The goal is to
solve typed XML traversal.

The simplest example that highlights its strength I gave in the first email.
Think of the descendent axis without having
to know all the types/functions to navigate.

Hope that helps.

Sumant.

> I understand the global idea but your examples are only about retrieving
> informations. Maybe I missed a more complete example?
>
> By the way, did you already setup some performance tests? Just to get an
> idea.
>
> On Tue, Nov 30, 2010 at 20:21, Sumant Tambe <sutambe_at_[hidden]> wrote:
>
> > Hello boosters!
> >
> > I'm interested in gauging interest in a typed XML traversal library that
> > combines the succinctness of XPath with the type-safety of XML
> data-binding
> > tools. I've been developing one such library called LEESA: Language for
> > Embedded Query and Traversal <http://www.dre.vanderbilt.edu/LEESA>.
> LEESA
> > has several capabilities:
> >
> >   1. Succinct and expressive XPath-like notation for writing object
> >   structure traversals
> >   2. Supports child, parent, sibling, descendant, ancestor axes
> >   3. Compile-time schema conformance checking
> >   4. Supports GOF visitors and hierarchical visitors
> >   5. Strategic Programming ... and more!
> >
> > Here are two quick examples comparing XPath and LEESA. More examples are
> > available on the LEESA homepage.
> >
> > XPath expression: "/catalog/book/author/name/text()"
> > LEESA expression:
> > *std::vector<name> author_names = evaluate(root, catalog() >> book() >>
> > author() >> name()); *
> >
> >
> > XPath expression: "//name/text()"
> > LEESA Expression:
> > *std::vector<name> names = evaluate(root, catalog() >>
> > DescendantsOf(catalog(), name())); *
> >
> > The above expressions are checked for schema-conformance at compile-time.
> > LEESA builds these capabilities on top of existing XML data binding tools
> > that generate C++ code from .xsd files. The general process of using
> LEESA
> > is as follows:
> >
> >   1. Generate C++ classes using your favorite XML data binding tool
> >   2. A python script that comes with LEESA adds a few functions in
> > every generated
> >   C++ class. It generates a lot of typedefs and helper functions, which
> >   invoke tool generated code. This creates a bridge between LEESA and the
> >   code generated by the xml data binding tool. Currently it supports Code
> >   Synthesis's xsd and Universal Data Model (UDM) from Vanderbilt
> University
> > as
> >   the underlying code generators.
> >   3. The user includes LEESA.h in his/her C++ program (it is
> > header-only), uses
> >   its programming model, compiles, and links with the tool generated code
> > and
> >   libraries.
> >
> > So folks, please speak up if you are interested in having such a library
> in
> > Boost.
> >
> > Thanks,
> >
> > Sumant
> > _______________________________________________
> > Unsubscribe & other changes:
> > http://lists.boost.org/mailman/listinfo.cgi/boost
> >
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