Hi,
Here is an alternate tool that can work in the way you want without
hacking the engine :
http://reflex.gforge.inria.fr/
it looks like Jelly in some points (it can run XML scripts in the order
of the tags), but it has also many differences :
-it doesn't rely on the UEL for referring variable but rather on XPath,
which allows you to cross XML documents and use XPath functions ; XPath
is also used for accessing some other non-XML objects such as a file
system : thus, if you use "//*" on a directory, you'll get the files
within the subtree
-it can be used for implementing declarative XML languages, that won't
be necessarily run in order, and additionally (if you are smart enough),
you can mix your declarative language with imperative constructs ; there
is an example of that concept in a schema language named ASL (the Active
Schema Language) ; it was presented at extreme markup language last
summer, and you might get the picture by browsing the slides and reading
the paper : http://reflex.gforge.inria.fr/eml2007.html
-it embeds lots of XML tools, such as SAX and DOM parsers (that you can
use transparently), an XPath-based filter that you can run on
extra-large XML inputs ; you can also use it to query various
datasources with SQL, XQuery, LDAP and map raw text to XML
-if your project deals with XML datas, there is a tool called XUnit that
works like JUnit that allows you to write and run test suites
etc, etc, etc
If you are interested, perhaps you could tell me more about your
project, then I could give you some tips for exposing your java classes
inside the XML tags of your declarative language with RefleX
Evaldas Taroza a écrit :
Hi,
Actually I already have a solution that works (i.e. I have some sort of
executable XML which has the needed logic), however, for me it is very
important to answer the question, would it be better to refactor that
solution in the way that it would use Jelly.
What I have is an engine (coincides with the Jelly script engine) that
is able to evaluate the XML documents with embedded executable parts.
These parts are simply XML tags in a special namespace. So for me it
looks completely like Jelly. The thing is that my engine is:
1. can only understand my tags in my namespace
2. can execute those tags in the order that I predefine (possibly inside
the tags)
3. during the execution of tags some new data can appear next to those
tags as a result of execution
Now the question: in order to transition to Jelly will I need to develop
taglibs only, or I will end up extending and modifying the jelly script
engine? I would really like it to be the former case:) do you think it
is reasonable?
Evaldas
Paul Libbrecht wrote:
Evaldas,
the jelly script is loaded in memory then the doTag methods are called.
So, of course, it could not scale to kilometers of source, but,
indeed, then a fancy branching logic of doTag is doable.
hope it helps.
paul
Le 10 déc. 07 à 09:42, Evaldas Taroza a écrit :
Hi,
Yes, I think I would need to implement something similar to the
thread taglib. Because I will need something like:
1. There is a dedicated thread for every tag
2. Some threads are blocked by other threads (waiting to end)
3. Unblocked threads can run
I haven't looked deep into Jelly yet, nor available taglibs, but what
worries me is that the script engine is like SAX, so will I be able
to construct a difficult "execution plan" with only one-pass parsing?
Evaldas
Paul Libbrecht wrote:
Evaldas,
I believe that the answer to your question is that it is flexible.
Jelly's default follows Ant and SAX: most tag's doTag call
invokeBody which produces a depth-first execution. The thread taglib
does it differently though.
You might be well served with Jelly although it still has some rough
edges.
paul
Le 9 déc. 07 à 17:16, Evaldas Taroza a écrit :
Hi,
I have a very specific usecase to program. Specifically, I need to
be able to execute the tags in a certain order. For instance, I
should be able to say that this tag is executing after another,
others can execute in parallel etc.
So I am considering Jelly as already implementing the execution of
the tags but what about the ordering? In what order are the tags
executed now? Is it at all feasible to use Jelly for such a usecase
or I will end up implementing a completely new Jelly script
evaluation engine?
Evaldas
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--
Cordialement,
///
(. .)
--------ooO--(_)--Ooo--------
| Philippe Poulard |
-----------------------------
http://reflex.gforge.inria.fr/
Have the RefleX !
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