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Posted to dev@xalan.apache.org by Qi Wang <wa...@gmail.com> on 2011/04/17 16:43:27 UTC
GSoC project "Implement XSLT 2.0 and XPath 2.0 for Xalan" need your advides
Hi all,
All Xalan developer and users, I wan to do something to push XSLT 2.0
implemention job for Xalan, i know this topic was discussed in mail list for
many many times in recent years, so many guys are expecting it come true.
But due to low activity in Apache Xalan community, no committer to push this
thing, it is really very regretful.
These days, i submited "Implement XSLT 2.0 and XPath 2.0 for Xalan" project
proposal as an GSoC[1] project. Now, i need your feedbacks to improve the
proposal, all the advises, suggestions are welcome :-)
I am not a Xalan committer(alrough i dream to be), but if there is a chance,
i want to try my best to so something for XSLT 2.0 implemention job for
Xalan, many i can not finish all the job in the summer, but i will make it
is available, once wheels start turn, i thing there may be some other guys
can work together with me to finish this big project. Hoping all the
comunity can work together for the better future of Xalan.
[1] http://socghop.appspot.com
=========Proposal details of "Implement XSLT 2.0 and XPath 2.0 for
Xalan"================
Apache Xalan-Java is a powful XSLT processor for XML transforming based on
W3C recommendation XSL Transformations (XSLT) Version 1.0 and XML Path
Language (XPath) Version 1.0, XSL Transformations (XSLT) Version 2.0
specification was published on 23 January 2007,this new version give us more
powful functions, new dat model and serialization etc.
In my daily work, i use XSLT and XPath to parse XML and change XML document
to another format, i did this with Xalan.As we know,Xalan support XSLT
version 1.0 and XPath version 1.0 only.But my XML parse job is so complex,
and usually, i must use some XPath v2.0 functions to finish my parse job.
So, i encountered trouble.
Then I Google keywords with Xalan and XSLT 2.0,i found many developers hope
that Xalan based XSLT 2.0 could become reality besides me. At the same time,
i discuss this topic with open source developers in mail list, so many guys
are interested in implementing complete XSTL 2.0 specification for Xalan. We
discuss this project deeply, and i got many good ideas and advises from the
discussion. And also they told me Xalan lost its most active contributors a
few years ago due to time demands from Real Jobs, and development slowed
down as a result,but they love to see Xalan tackle it.Due to XSLT 2.0 and
XPath 2.0 are large specifications that I imagine could take the developers
years to implement correctly,anyway it need some guy get the ball rolling, i
want to be this guy.
Compared with XSLT 1.0, XSLT 2.0 and XPath 2.0 have some important new
characteristic.
New features in XPath 2.0:
1. Sequences, in XPath2.0 everything is sequences
2. For expression,in XPath 2.0,we can use for expression to iterator
every item in the sequence, compute expression value for each item, at last
return the sequence result by connect all the expression values.
3. Condition expression, XPath 2.0's condition expression can be used to
compute different value on the basis of the condition's true or false value.
4. Limited expression,limited expression in XPath 2.0 can be used to
judge that whether every item in the sequence satisfy appointed condition,
its value is always true of false. There are two kinds of limited
expression: some expression and every expression.
5. Datatype,XPath 2.0's datetype is based on XML Schema, it supports all
the basic built-in datatype,such as xs:integer,xs:string and xs:date ect.
6. Date and time, XSLT 1.0 has not date and time datatype, it must use
string to represent date and time. Due to XPath 2.0 system is based on XML
schema, so there is date and time data type in XPath 2.0.
7. More functions support,XSLT 2.0 specification has more powful
functions definition.Functions in XPath 2.0 is defined in a special
recommedation "XQuery 1.0 and XPath 2.0 Functions and Operations", functions
in this recommendation specification belong to namespace "
http://www.w3.org/2005/xpath-functions", this namespace is bound with prefix
"fn".
It includes these serveral types:
* Constructor Functions
* Functions and Operators on Numerics
* Functions on Strings
* Functions on anyURI
* Functions and Operators on Boolean Values
* Functions and Operators on Durations, Dates and Times
* Functions Related to QNames
* Operators on base64Binary and hexBinary
* Operators on NOTATION
* Functions and Operators on Nodes
* Functions and Operators on Sequences
* Context Functions
There are also many new features in XSLT 2.0:
1. Group, basic group syntax,group sort,group-adjacent and
group-starting-with etc.
2. Connotive document node, or we can call it temporary tree
3. Element result-document, we can use to generate multi output file in
XPath 2.0
4. Improvement of element value-of
5. Char mapping,XSLT 2.0 supply more flexible solution for us to handler
specific characters in XML such as '<' and '&'
6. Custom stylesheet function,in XSLT 2.0, we can use to create our own
functions in stylesheet
7. Other new features.
In order to implement all the XSLT 2.0 specification,it requires some
moderately basic data structure changes to track Schema types and to handle
Sequences which aren't simply nodesets,and also,i must implements all the
new functions defined in XSLT 2.0,fortunately,there is a open source XPath
2.0 processor (http://wiki.eclipse.org/PsychoPathXPathProcessor) which is at
Eclipse.It is already being used by Xerces-J for XSD 1.1 Assertion
support.Why re-invent the wheel if we can leverage something that already
exists ? PsychoPath already is XML Schema Aware, leverages Xerces-J(
http://xerces.apache.org/xerces2-j) and passes about 99.9% of the Xpath 2.0
test suite. It is currently undergoing testing against the the official W3C
Test Suite.
So, in order to implement all the XSLT 2.0 specification for Xalan, there
are two steps:
1. Merge Xalan codes with PsychoPath codes,this will help us a lot,once
this job is done, Xalan has implemented all the XPath 2.0 features. There
are some issues to resolve during this merging process,for example:
* PsychoPath is not "streamy" yet, nor is Xalan, it is a big
challenge
* In PsychoPath,type informations is not part of current
interfaces,i will have to extend or replace the DTM interfaces to carry the
additional data
* XSLTC fit in problem. XSLTC runs against the same data model
interfaces (DTM), and In Theory implementing compilation should just be a
matter of generating code equivalent to what the interpreter is doing. In
practice, it's a lot of detail work.
2. Implement all the other XSLT 2.0 features which were described before
for Xalan.
In my plan, i will hold the whole XSLT 2.0 implemention project as a long
term open source project under Apache, do it step by step, may be as a GSoC
project,i can only implement a subset of this capability i was thinking of
working on,at lease, i will finish the following tasks:
1. Merge Xalan codes with PsychoPath codes, i will do this first, but
this is not a simple task,may be it will cost me one month or even more to
merge it correctly.
2. Resolve merge problems between Xalan and PsychoPath
3. Implement XSLT 2.0 Group feature for Xalan
4. Implement XSLT 2.0 temporary tree feature for Xalan
5. Implement Element result-document feature for Xalan
If everything goes well and i have enough time,i will do my best to do more
job. After the summer, i will continue with this project,try to submit my
codes to Xalan as proposed changes and try to become one of Apache
committers,this is my dream.And i know this is a huge project,but where
there is a will there is a success, I love open source, i will do my best to
improve it through my attemp and ability.
Regards
Victor Wang
Re: GSoC project "Implement XSLT 2.0 and XPath 2.0 for Xalan" need
your advides
Posted by Xun Long Gui <us...@gmail.com>.
Hi Qi,
Please let us know once your finished your first version of code submit job
2011/4/18 Qi Wang <wa...@gmail.com>
> Hi Jesper,
>
> Thank you for your interest, I am working for the design details and have
> start this implementation job, i will hold the code base and relative
> documents in Google Code web site soon, as this is really a huge project,
> hoping more guys are participate in this project together :-)
>
>
> 2011/4/18 Jesper Steen Møller <je...@selskabet.org>
>
>> Hello Qi Wang
>>
>> I think this is a really good idea!
>>
>> I am one of the developers of the XPath2 engine at the Eclipse WTP project
>> (in fact I don't know much Xalan-J, actually I just contributed two Xalan-J
>> bug fixes which were never picked up)
>>
>> For the release this summer (Indigo), a new API has been introduced which
>> allows pluggable type models, and allows much better access to the XPath2
>> engine without using internal packages. Also, the library uses a better
>> structure for separating the parsing and execution of the expression. Also,
>> we will now be JRE 1.4 compatible (sigh).
>>
>> Lots of improvements you can use there.
>>
>> However, "PsychoPath" (I hate that name) is still bound to using a Level 3
>> DOM, and no, we do not have a streamy front end. The internal tree
>> implementation for Xalan would thus have to be wrapped for use with the
>> Eclipse XPath2 engine. But for type-sensitive template handling, this might
>> not be sufficient anyway. So you will face quite a number of challenges!
>>
>> Also, I hope you can do all this without having to fork the XPath2 engine,
>> since it is also used elsewhere, but we might be able to "semi fork" it and
>> work your changes back into the mainline for the next major release.
>>
>> As for how to work with the Xalan codebase, I cannot provide guidance on
>> your overall strategy, I think the Xalan-J people can guide you much better
>> there.
>>
>> Kind regards,
>> Jesper Steen Møller
>>
>> On 17/04/2011, at 16.43, Qi Wang wrote:
>>
>> Hi all,
>>
>> All Xalan developer and users, I wan to do something to push XSLT 2.0
>> implemention job for Xalan, i know this topic was discussed in mail list for
>> many many times in recent years, so many guys are expecting it come true.
>> But due to low activity in Apache Xalan community, no committer to push this
>> thing, it is really very regretful.
>>
>> These days, i submited "Implement XSLT 2.0 and XPath 2.0 for Xalan"
>> project proposal as an GSoC[1] project. Now, i need your feedbacks to
>> improve the proposal, all the advises, suggestions are welcome :-)
>>
>> I am not a Xalan committer(alrough i dream to be), but if there is a
>> chance, i want to try my best to so something for XSLT 2.0 implemention job
>> for Xalan, many i can not finish all the job in the summer, but i will make
>> it is available, once wheels start turn, i thing there may be some other
>> guys can work together with me to finish this big project. Hoping all the
>> comunity can work together for the better future of Xalan.
>>
>> [1] http://socghop.appspot.com
>>
>> =========Proposal details of "Implement XSLT 2.0 and XPath 2.0 for
>> Xalan"================
>>
>> Apache Xalan-Java is a powful XSLT processor for XML transforming based on
>> W3C recommendation XSL Transformations (XSLT) Version 1.0 and XML Path
>> Language (XPath) Version 1.0, XSL Transformations (XSLT) Version 2.0
>> specification was published on 23 January 2007,this new version give us more
>> powful functions, new dat model and serialization etc.
>>
>>
>>
>> In my daily work, i use XSLT and XPath to parse XML and change XML
>> document to another format, i did this with Xalan.As we know,Xalan support
>> XSLT version 1.0 and XPath version 1.0 only.But my XML parse job is so
>> complex, and usually, i must use some XPath v2.0 functions to finish my
>> parse job. So, i encountered trouble.
>>
>>
>>
>> Then I Google keywords with Xalan and XSLT 2.0,i found many developers
>> hope that Xalan based XSLT 2.0 could become reality besides me. At the same
>> time, i discuss this topic with open source developers in mail list, so many
>> guys are interested in implementing complete XSTL 2.0 specification for
>> Xalan. We discuss this project deeply, and i got many good ideas and advises
>> from the discussion. And also they told me Xalan lost its most active
>> contributors a few years ago due to time demands from Real Jobs, and
>> development slowed down as a result,but they love to see Xalan tackle it.Due
>> to XSLT 2.0 and XPath 2.0 are large specifications that I imagine could take
>> the developers years to implement correctly,anyway it need some guy get the
>> ball rolling, i want to be this guy.
>>
>>
>>
>> Compared with XSLT 1.0, XSLT 2.0 and XPath 2.0 have some important new
>> characteristic.
>>
>>
>>
>> New features in XPath 2.0:
>>
>> 1. Sequences, in XPath2.0 everything is sequences
>> 2. For expression,in XPath 2.0,we can use for expression to iterator
>> every item in the sequence, compute expression value for each item, at last
>> return the sequence result by connect all the expression values.
>> 3. Condition expression, XPath 2.0's condition expression can be used
>> to compute different value on the basis of the condition's true or false
>> value.
>> 4. Limited expression,limited expression in XPath 2.0 can be used to
>> judge that whether every item in the sequence satisfy appointed condition,
>> its value is always true of false. There are two kinds of limited
>> expression: some expression and every expression.
>> 5. Datatype,XPath 2.0's datetype is based on XML Schema, it supports
>> all the basic built-in datatype,such as xs:integer,xs:string and xs:date
>> ect.
>> 6. Date and time, XSLT 1.0 has not date and time datatype, it must use
>> string to represent date and time. Due to XPath 2.0 system is based on XML
>> schema, so there is date and time data type in XPath 2.0.
>> 7. More functions support,XSLT 2.0 specification has more powful
>> functions definition.Functions in XPath 2.0 is defined in a special
>> recommedation "XQuery 1.0 and XPath 2.0 Functions and Operations", functions
>> in this recommendation specification belong to namespace "
>> http://www.w3.org/2005/xpath-functions", this namespace is bound with
>> prefix "fn".
>>
>> It includes these serveral types:
>>
>> * Constructor Functions
>> * Functions and Operators on Numerics
>> * Functions on Strings
>> * Functions on anyURI
>> * Functions and Operators on Boolean Values
>> * Functions and Operators on Durations, Dates and Times
>> * Functions Related to QNames
>> * Operators on base64Binary and hexBinary
>> * Operators on NOTATION
>> * Functions and Operators on Nodes
>> * Functions and Operators on Sequences
>> * Context Functions
>>
>> There are also many new features in XSLT 2.0:
>>
>> 1. Group, basic group syntax,group sort,group-adjacent and
>> group-starting-with etc.
>> 2. Connotive document node, or we can call it temporary tree
>> 3. Element result-document, we can use to generate multi output file in
>> XPath 2.0
>> 4. Improvement of element value-of
>> 5. Char mapping,XSLT 2.0 supply more flexible solution for us to
>> handler specific characters in XML such as '<' and '&'
>> 6. Custom stylesheet function,in XSLT 2.0, we can use to create our own
>> functions in stylesheet
>> 7. Other new features.
>>
>> In order to implement all the XSLT 2.0 specification,it requires some
>> moderately basic data structure changes to track Schema types and to handle
>> Sequences which aren't simply nodesets,and also,i must implements all the
>> new functions defined in XSLT 2.0,fortunately,there is a open source XPath
>> 2.0 processor (http://wiki.eclipse.org/PsychoPathXPathProcessor) which is
>> at Eclipse.It is already being used by Xerces-J for XSD 1.1 Assertion
>> support.Why re-invent the wheel if we can leverage something that already
>> exists ? PsychoPath already is XML Schema Aware, leverages Xerces-J(
>> http://xerces.apache.org/xerces2-j) and passes about 99.9% of the Xpath
>> 2.0 test suite. It is currently undergoing testing against the the official
>> W3C Test Suite.
>>
>>
>>
>> So, in order to implement all the XSLT 2.0 specification for Xalan, there
>> are two steps:
>>
>> 1. Merge Xalan codes with PsychoPath codes,this will help us a lot,once
>> this job is done, Xalan has implemented all the XPath 2.0 features. There
>> are some issues to resolve during this merging process,for example:
>> * PsychoPath is not "streamy" yet, nor is Xalan, it is a big
>> challenge
>> * In PsychoPath,type informations is not part of current
>> interfaces,i will have to extend or replace the DTM interfaces to carry the
>> additional data
>> * XSLTC fit in problem. XSLTC runs against the same data model
>> interfaces (DTM), and In Theory implementing compilation should just be a
>> matter of generating code equivalent to what the interpreter is doing. In
>> practice, it's a lot of detail work.
>> 2. Implement all the other XSLT 2.0 features which were described
>> before for Xalan.
>>
>> In my plan, i will hold the whole XSLT 2.0 implemention project as a long
>> term open source project under Apache, do it step by step, may be as a GSoC
>> project,i can only implement a subset of this capability i was thinking of
>> working on,at lease, i will finish the following tasks:
>>
>> 1. Merge Xalan codes with PsychoPath codes, i will do this first, but
>> this is not a simple task,may be it will cost me one month or even more to
>> merge it correctly.
>> 2. Resolve merge problems between Xalan and PsychoPath
>> 3. Implement XSLT 2.0 Group feature for Xalan
>> 4. Implement XSLT 2.0 temporary tree feature for Xalan
>> 5. Implement Element result-document feature for Xalan
>>
>> If everything goes well and i have enough time,i will do my best to do
>> more job. After the summer, i will continue with this project,try to submit
>> my codes to Xalan as proposed changes and try to become one of Apache
>> committers,this is my dream.And i know this is a huge project,but where
>> there is a will there is a success, I love open source, i will do my best to
>> improve it through my attemp and ability.
>>
>>
>> Regards
>>
>> Victor Wang
>>
>>
>>
>
--
Best Regards
Gui Xun Long (桂训龙)
Re: GSoC project "Implement XSLT 2.0 and XPath 2.0 for Xalan" need
your advides
Posted by Xun Long Gui <us...@gmail.com>.
Hi Qi,
Please let us know once your finished your first version of code submit job
2011/4/18 Qi Wang <wa...@gmail.com>
> Hi Jesper,
>
> Thank you for your interest, I am working for the design details and have
> start this implementation job, i will hold the code base and relative
> documents in Google Code web site soon, as this is really a huge project,
> hoping more guys are participate in this project together :-)
>
>
> 2011/4/18 Jesper Steen Møller <je...@selskabet.org>
>
>> Hello Qi Wang
>>
>> I think this is a really good idea!
>>
>> I am one of the developers of the XPath2 engine at the Eclipse WTP project
>> (in fact I don't know much Xalan-J, actually I just contributed two Xalan-J
>> bug fixes which were never picked up)
>>
>> For the release this summer (Indigo), a new API has been introduced which
>> allows pluggable type models, and allows much better access to the XPath2
>> engine without using internal packages. Also, the library uses a better
>> structure for separating the parsing and execution of the expression. Also,
>> we will now be JRE 1.4 compatible (sigh).
>>
>> Lots of improvements you can use there.
>>
>> However, "PsychoPath" (I hate that name) is still bound to using a Level 3
>> DOM, and no, we do not have a streamy front end. The internal tree
>> implementation for Xalan would thus have to be wrapped for use with the
>> Eclipse XPath2 engine. But for type-sensitive template handling, this might
>> not be sufficient anyway. So you will face quite a number of challenges!
>>
>> Also, I hope you can do all this without having to fork the XPath2 engine,
>> since it is also used elsewhere, but we might be able to "semi fork" it and
>> work your changes back into the mainline for the next major release.
>>
>> As for how to work with the Xalan codebase, I cannot provide guidance on
>> your overall strategy, I think the Xalan-J people can guide you much better
>> there.
>>
>> Kind regards,
>> Jesper Steen Møller
>>
>> On 17/04/2011, at 16.43, Qi Wang wrote:
>>
>> Hi all,
>>
>> All Xalan developer and users, I wan to do something to push XSLT 2.0
>> implemention job for Xalan, i know this topic was discussed in mail list for
>> many many times in recent years, so many guys are expecting it come true.
>> But due to low activity in Apache Xalan community, no committer to push this
>> thing, it is really very regretful.
>>
>> These days, i submited "Implement XSLT 2.0 and XPath 2.0 for Xalan"
>> project proposal as an GSoC[1] project. Now, i need your feedbacks to
>> improve the proposal, all the advises, suggestions are welcome :-)
>>
>> I am not a Xalan committer(alrough i dream to be), but if there is a
>> chance, i want to try my best to so something for XSLT 2.0 implemention job
>> for Xalan, many i can not finish all the job in the summer, but i will make
>> it is available, once wheels start turn, i thing there may be some other
>> guys can work together with me to finish this big project. Hoping all the
>> comunity can work together for the better future of Xalan.
>>
>> [1] http://socghop.appspot.com
>>
>> =========Proposal details of "Implement XSLT 2.0 and XPath 2.0 for
>> Xalan"================
>>
>> Apache Xalan-Java is a powful XSLT processor for XML transforming based on
>> W3C recommendation XSL Transformations (XSLT) Version 1.0 and XML Path
>> Language (XPath) Version 1.0, XSL Transformations (XSLT) Version 2.0
>> specification was published on 23 January 2007,this new version give us more
>> powful functions, new dat model and serialization etc.
>>
>>
>>
>> In my daily work, i use XSLT and XPath to parse XML and change XML
>> document to another format, i did this with Xalan.As we know,Xalan support
>> XSLT version 1.0 and XPath version 1.0 only.But my XML parse job is so
>> complex, and usually, i must use some XPath v2.0 functions to finish my
>> parse job. So, i encountered trouble.
>>
>>
>>
>> Then I Google keywords with Xalan and XSLT 2.0,i found many developers
>> hope that Xalan based XSLT 2.0 could become reality besides me. At the same
>> time, i discuss this topic with open source developers in mail list, so many
>> guys are interested in implementing complete XSTL 2.0 specification for
>> Xalan. We discuss this project deeply, and i got many good ideas and advises
>> from the discussion. And also they told me Xalan lost its most active
>> contributors a few years ago due to time demands from Real Jobs, and
>> development slowed down as a result,but they love to see Xalan tackle it.Due
>> to XSLT 2.0 and XPath 2.0 are large specifications that I imagine could take
>> the developers years to implement correctly,anyway it need some guy get the
>> ball rolling, i want to be this guy.
>>
>>
>>
>> Compared with XSLT 1.0, XSLT 2.0 and XPath 2.0 have some important new
>> characteristic.
>>
>>
>>
>> New features in XPath 2.0:
>>
>> 1. Sequences, in XPath2.0 everything is sequences
>> 2. For expression,in XPath 2.0,we can use for expression to iterator
>> every item in the sequence, compute expression value for each item, at last
>> return the sequence result by connect all the expression values.
>> 3. Condition expression, XPath 2.0's condition expression can be used
>> to compute different value on the basis of the condition's true or false
>> value.
>> 4. Limited expression,limited expression in XPath 2.0 can be used to
>> judge that whether every item in the sequence satisfy appointed condition,
>> its value is always true of false. There are two kinds of limited
>> expression: some expression and every expression.
>> 5. Datatype,XPath 2.0's datetype is based on XML Schema, it supports
>> all the basic built-in datatype,such as xs:integer,xs:string and xs:date
>> ect.
>> 6. Date and time, XSLT 1.0 has not date and time datatype, it must use
>> string to represent date and time. Due to XPath 2.0 system is based on XML
>> schema, so there is date and time data type in XPath 2.0.
>> 7. More functions support,XSLT 2.0 specification has more powful
>> functions definition.Functions in XPath 2.0 is defined in a special
>> recommedation "XQuery 1.0 and XPath 2.0 Functions and Operations", functions
>> in this recommendation specification belong to namespace "
>> http://www.w3.org/2005/xpath-functions", this namespace is bound with
>> prefix "fn".
>>
>> It includes these serveral types:
>>
>> * Constructor Functions
>> * Functions and Operators on Numerics
>> * Functions on Strings
>> * Functions on anyURI
>> * Functions and Operators on Boolean Values
>> * Functions and Operators on Durations, Dates and Times
>> * Functions Related to QNames
>> * Operators on base64Binary and hexBinary
>> * Operators on NOTATION
>> * Functions and Operators on Nodes
>> * Functions and Operators on Sequences
>> * Context Functions
>>
>> There are also many new features in XSLT 2.0:
>>
>> 1. Group, basic group syntax,group sort,group-adjacent and
>> group-starting-with etc.
>> 2. Connotive document node, or we can call it temporary tree
>> 3. Element result-document, we can use to generate multi output file in
>> XPath 2.0
>> 4. Improvement of element value-of
>> 5. Char mapping,XSLT 2.0 supply more flexible solution for us to
>> handler specific characters in XML such as '<' and '&'
>> 6. Custom stylesheet function,in XSLT 2.0, we can use to create our own
>> functions in stylesheet
>> 7. Other new features.
>>
>> In order to implement all the XSLT 2.0 specification,it requires some
>> moderately basic data structure changes to track Schema types and to handle
>> Sequences which aren't simply nodesets,and also,i must implements all the
>> new functions defined in XSLT 2.0,fortunately,there is a open source XPath
>> 2.0 processor (http://wiki.eclipse.org/PsychoPathXPathProcessor) which is
>> at Eclipse.It is already being used by Xerces-J for XSD 1.1 Assertion
>> support.Why re-invent the wheel if we can leverage something that already
>> exists ? PsychoPath already is XML Schema Aware, leverages Xerces-J(
>> http://xerces.apache.org/xerces2-j) and passes about 99.9% of the Xpath
>> 2.0 test suite. It is currently undergoing testing against the the official
>> W3C Test Suite.
>>
>>
>>
>> So, in order to implement all the XSLT 2.0 specification for Xalan, there
>> are two steps:
>>
>> 1. Merge Xalan codes with PsychoPath codes,this will help us a lot,once
>> this job is done, Xalan has implemented all the XPath 2.0 features. There
>> are some issues to resolve during this merging process,for example:
>> * PsychoPath is not "streamy" yet, nor is Xalan, it is a big
>> challenge
>> * In PsychoPath,type informations is not part of current
>> interfaces,i will have to extend or replace the DTM interfaces to carry the
>> additional data
>> * XSLTC fit in problem. XSLTC runs against the same data model
>> interfaces (DTM), and In Theory implementing compilation should just be a
>> matter of generating code equivalent to what the interpreter is doing. In
>> practice, it's a lot of detail work.
>> 2. Implement all the other XSLT 2.0 features which were described
>> before for Xalan.
>>
>> In my plan, i will hold the whole XSLT 2.0 implemention project as a long
>> term open source project under Apache, do it step by step, may be as a GSoC
>> project,i can only implement a subset of this capability i was thinking of
>> working on,at lease, i will finish the following tasks:
>>
>> 1. Merge Xalan codes with PsychoPath codes, i will do this first, but
>> this is not a simple task,may be it will cost me one month or even more to
>> merge it correctly.
>> 2. Resolve merge problems between Xalan and PsychoPath
>> 3. Implement XSLT 2.0 Group feature for Xalan
>> 4. Implement XSLT 2.0 temporary tree feature for Xalan
>> 5. Implement Element result-document feature for Xalan
>>
>> If everything goes well and i have enough time,i will do my best to do
>> more job. After the summer, i will continue with this project,try to submit
>> my codes to Xalan as proposed changes and try to become one of Apache
>> committers,this is my dream.And i know this is a huge project,but where
>> there is a will there is a success, I love open source, i will do my best to
>> improve it through my attemp and ability.
>>
>>
>> Regards
>>
>> Victor Wang
>>
>>
>>
>
--
Best Regards
Gui Xun Long (桂训龙)
Re: GSoC project "Implement XSLT 2.0 and XPath 2.0 for Xalan" need
your advides
Posted by Qi Wang <wa...@gmail.com>.
Hi Jesper,
Thank you for your interest, I am working for the design details and have
start this implementation job, i will hold the code base and relative
documents in Google Code web site soon, as this is really a huge project,
hoping more guys are participate in this project together :-)
2011/4/18 Jesper Steen Møller <je...@selskabet.org>
> Hello Qi Wang
>
> I think this is a really good idea!
>
> I am one of the developers of the XPath2 engine at the Eclipse WTP project
> (in fact I don't know much Xalan-J, actually I just contributed two Xalan-J
> bug fixes which were never picked up)
>
> For the release this summer (Indigo), a new API has been introduced which
> allows pluggable type models, and allows much better access to the XPath2
> engine without using internal packages. Also, the library uses a better
> structure for separating the parsing and execution of the expression. Also,
> we will now be JRE 1.4 compatible (sigh).
>
> Lots of improvements you can use there.
>
> However, "PsychoPath" (I hate that name) is still bound to using a Level 3
> DOM, and no, we do not have a streamy front end. The internal tree
> implementation for Xalan would thus have to be wrapped for use with the
> Eclipse XPath2 engine. But for type-sensitive template handling, this might
> not be sufficient anyway. So you will face quite a number of challenges!
>
> Also, I hope you can do all this without having to fork the XPath2 engine,
> since it is also used elsewhere, but we might be able to "semi fork" it and
> work your changes back into the mainline for the next major release.
>
> As for how to work with the Xalan codebase, I cannot provide guidance on
> your overall strategy, I think the Xalan-J people can guide you much better
> there.
>
> Kind regards,
> Jesper Steen Møller
>
> On 17/04/2011, at 16.43, Qi Wang wrote:
>
> Hi all,
>
> All Xalan developer and users, I wan to do something to push XSLT 2.0
> implemention job for Xalan, i know this topic was discussed in mail list for
> many many times in recent years, so many guys are expecting it come true.
> But due to low activity in Apache Xalan community, no committer to push this
> thing, it is really very regretful.
>
> These days, i submited "Implement XSLT 2.0 and XPath 2.0 for Xalan" project
> proposal as an GSoC[1] project. Now, i need your feedbacks to improve the
> proposal, all the advises, suggestions are welcome :-)
>
> I am not a Xalan committer(alrough i dream to be), but if there is a
> chance, i want to try my best to so something for XSLT 2.0 implemention job
> for Xalan, many i can not finish all the job in the summer, but i will make
> it is available, once wheels start turn, i thing there may be some other
> guys can work together with me to finish this big project. Hoping all the
> comunity can work together for the better future of Xalan.
>
> [1] http://socghop.appspot.com
>
> =========Proposal details of "Implement XSLT 2.0 and XPath 2.0 for
> Xalan"================
>
> Apache Xalan-Java is a powful XSLT processor for XML transforming based on
> W3C recommendation XSL Transformations (XSLT) Version 1.0 and XML Path
> Language (XPath) Version 1.0, XSL Transformations (XSLT) Version 2.0
> specification was published on 23 January 2007,this new version give us more
> powful functions, new dat model and serialization etc.
>
>
>
> In my daily work, i use XSLT and XPath to parse XML and change XML document
> to another format, i did this with Xalan.As we know,Xalan support XSLT
> version 1.0 and XPath version 1.0 only.But my XML parse job is so complex,
> and usually, i must use some XPath v2.0 functions to finish my parse job.
> So, i encountered trouble.
>
>
>
> Then I Google keywords with Xalan and XSLT 2.0,i found many developers hope
> that Xalan based XSLT 2.0 could become reality besides me. At the same time,
> i discuss this topic with open source developers in mail list, so many guys
> are interested in implementing complete XSTL 2.0 specification for Xalan. We
> discuss this project deeply, and i got many good ideas and advises from the
> discussion. And also they told me Xalan lost its most active contributors a
> few years ago due to time demands from Real Jobs, and development slowed
> down as a result,but they love to see Xalan tackle it.Due to XSLT 2.0 and
> XPath 2.0 are large specifications that I imagine could take the developers
> years to implement correctly,anyway it need some guy get the ball rolling, i
> want to be this guy.
>
>
>
> Compared with XSLT 1.0, XSLT 2.0 and XPath 2.0 have some important new
> characteristic.
>
>
>
> New features in XPath 2.0:
>
> 1. Sequences, in XPath2.0 everything is sequences
> 2. For expression,in XPath 2.0,we can use for expression to iterator
> every item in the sequence, compute expression value for each item, at last
> return the sequence result by connect all the expression values.
> 3. Condition expression, XPath 2.0's condition expression can be used to
> compute different value on the basis of the condition's true or false value.
> 4. Limited expression,limited expression in XPath 2.0 can be used to
> judge that whether every item in the sequence satisfy appointed condition,
> its value is always true of false. There are two kinds of limited
> expression: some expression and every expression.
> 5. Datatype,XPath 2.0's datetype is based on XML Schema, it supports all
> the basic built-in datatype,such as xs:integer,xs:string and xs:date ect.
> 6. Date and time, XSLT 1.0 has not date and time datatype, it must use
> string to represent date and time. Due to XPath 2.0 system is based on XML
> schema, so there is date and time data type in XPath 2.0.
> 7. More functions support,XSLT 2.0 specification has more powful
> functions definition.Functions in XPath 2.0 is defined in a special
> recommedation "XQuery 1.0 and XPath 2.0 Functions and Operations", functions
> in this recommendation specification belong to namespace "
> http://www.w3.org/2005/xpath-functions", this namespace is bound with
> prefix "fn".
>
> It includes these serveral types:
>
> * Constructor Functions
> * Functions and Operators on Numerics
> * Functions on Strings
> * Functions on anyURI
> * Functions and Operators on Boolean Values
> * Functions and Operators on Durations, Dates and Times
> * Functions Related to QNames
> * Operators on base64Binary and hexBinary
> * Operators on NOTATION
> * Functions and Operators on Nodes
> * Functions and Operators on Sequences
> * Context Functions
>
> There are also many new features in XSLT 2.0:
>
> 1. Group, basic group syntax,group sort,group-adjacent and
> group-starting-with etc.
> 2. Connotive document node, or we can call it temporary tree
> 3. Element result-document, we can use to generate multi output file in
> XPath 2.0
> 4. Improvement of element value-of
> 5. Char mapping,XSLT 2.0 supply more flexible solution for us to handler
> specific characters in XML such as '<' and '&'
> 6. Custom stylesheet function,in XSLT 2.0, we can use to create our own
> functions in stylesheet
> 7. Other new features.
>
> In order to implement all the XSLT 2.0 specification,it requires some
> moderately basic data structure changes to track Schema types and to handle
> Sequences which aren't simply nodesets,and also,i must implements all the
> new functions defined in XSLT 2.0,fortunately,there is a open source XPath
> 2.0 processor (http://wiki.eclipse.org/PsychoPathXPathProcessor) which is
> at Eclipse.It is already being used by Xerces-J for XSD 1.1 Assertion
> support.Why re-invent the wheel if we can leverage something that already
> exists ? PsychoPath already is XML Schema Aware, leverages Xerces-J(
> http://xerces.apache.org/xerces2-j) and passes about 99.9% of the Xpath
> 2.0 test suite. It is currently undergoing testing against the the official
> W3C Test Suite.
>
>
>
> So, in order to implement all the XSLT 2.0 specification for Xalan, there
> are two steps:
>
> 1. Merge Xalan codes with PsychoPath codes,this will help us a lot,once
> this job is done, Xalan has implemented all the XPath 2.0 features. There
> are some issues to resolve during this merging process,for example:
> * PsychoPath is not "streamy" yet, nor is Xalan, it is a big
> challenge
> * In PsychoPath,type informations is not part of current
> interfaces,i will have to extend or replace the DTM interfaces to carry the
> additional data
> * XSLTC fit in problem. XSLTC runs against the same data model
> interfaces (DTM), and In Theory implementing compilation should just be a
> matter of generating code equivalent to what the interpreter is doing. In
> practice, it's a lot of detail work.
> 2. Implement all the other XSLT 2.0 features which were described before
> for Xalan.
>
> In my plan, i will hold the whole XSLT 2.0 implemention project as a long
> term open source project under Apache, do it step by step, may be as a GSoC
> project,i can only implement a subset of this capability i was thinking of
> working on,at lease, i will finish the following tasks:
>
> 1. Merge Xalan codes with PsychoPath codes, i will do this first, but
> this is not a simple task,may be it will cost me one month or even more to
> merge it correctly.
> 2. Resolve merge problems between Xalan and PsychoPath
> 3. Implement XSLT 2.0 Group feature for Xalan
> 4. Implement XSLT 2.0 temporary tree feature for Xalan
> 5. Implement Element result-document feature for Xalan
>
> If everything goes well and i have enough time,i will do my best to do more
> job. After the summer, i will continue with this project,try to submit my
> codes to Xalan as proposed changes and try to become one of Apache
> committers,this is my dream.And i know this is a huge project,but where
> there is a will there is a success, I love open source, i will do my best to
> improve it through my attemp and ability.
>
>
> Regards
>
> Victor Wang
>
>
>
Re: GSoC project "Implement XSLT 2.0 and XPath 2.0 for Xalan" need
your advides
Posted by Qi Wang <wa...@gmail.com>.
Hi Jesper,
Thank you for your interest, I am working for the design details and have
start this implementation job, i will hold the code base and relative
documents in Google Code web site soon, as this is really a huge project,
hoping more guys are participate in this project together :-)
2011/4/18 Jesper Steen Møller <je...@selskabet.org>
> Hello Qi Wang
>
> I think this is a really good idea!
>
> I am one of the developers of the XPath2 engine at the Eclipse WTP project
> (in fact I don't know much Xalan-J, actually I just contributed two Xalan-J
> bug fixes which were never picked up)
>
> For the release this summer (Indigo), a new API has been introduced which
> allows pluggable type models, and allows much better access to the XPath2
> engine without using internal packages. Also, the library uses a better
> structure for separating the parsing and execution of the expression. Also,
> we will now be JRE 1.4 compatible (sigh).
>
> Lots of improvements you can use there.
>
> However, "PsychoPath" (I hate that name) is still bound to using a Level 3
> DOM, and no, we do not have a streamy front end. The internal tree
> implementation for Xalan would thus have to be wrapped for use with the
> Eclipse XPath2 engine. But for type-sensitive template handling, this might
> not be sufficient anyway. So you will face quite a number of challenges!
>
> Also, I hope you can do all this without having to fork the XPath2 engine,
> since it is also used elsewhere, but we might be able to "semi fork" it and
> work your changes back into the mainline for the next major release.
>
> As for how to work with the Xalan codebase, I cannot provide guidance on
> your overall strategy, I think the Xalan-J people can guide you much better
> there.
>
> Kind regards,
> Jesper Steen Møller
>
> On 17/04/2011, at 16.43, Qi Wang wrote:
>
> Hi all,
>
> All Xalan developer and users, I wan to do something to push XSLT 2.0
> implemention job for Xalan, i know this topic was discussed in mail list for
> many many times in recent years, so many guys are expecting it come true.
> But due to low activity in Apache Xalan community, no committer to push this
> thing, it is really very regretful.
>
> These days, i submited "Implement XSLT 2.0 and XPath 2.0 for Xalan" project
> proposal as an GSoC[1] project. Now, i need your feedbacks to improve the
> proposal, all the advises, suggestions are welcome :-)
>
> I am not a Xalan committer(alrough i dream to be), but if there is a
> chance, i want to try my best to so something for XSLT 2.0 implemention job
> for Xalan, many i can not finish all the job in the summer, but i will make
> it is available, once wheels start turn, i thing there may be some other
> guys can work together with me to finish this big project. Hoping all the
> comunity can work together for the better future of Xalan.
>
> [1] http://socghop.appspot.com
>
> =========Proposal details of "Implement XSLT 2.0 and XPath 2.0 for
> Xalan"================
>
> Apache Xalan-Java is a powful XSLT processor for XML transforming based on
> W3C recommendation XSL Transformations (XSLT) Version 1.0 and XML Path
> Language (XPath) Version 1.0, XSL Transformations (XSLT) Version 2.0
> specification was published on 23 January 2007,this new version give us more
> powful functions, new dat model and serialization etc.
>
>
>
> In my daily work, i use XSLT and XPath to parse XML and change XML document
> to another format, i did this with Xalan.As we know,Xalan support XSLT
> version 1.0 and XPath version 1.0 only.But my XML parse job is so complex,
> and usually, i must use some XPath v2.0 functions to finish my parse job.
> So, i encountered trouble.
>
>
>
> Then I Google keywords with Xalan and XSLT 2.0,i found many developers hope
> that Xalan based XSLT 2.0 could become reality besides me. At the same time,
> i discuss this topic with open source developers in mail list, so many guys
> are interested in implementing complete XSTL 2.0 specification for Xalan. We
> discuss this project deeply, and i got many good ideas and advises from the
> discussion. And also they told me Xalan lost its most active contributors a
> few years ago due to time demands from Real Jobs, and development slowed
> down as a result,but they love to see Xalan tackle it.Due to XSLT 2.0 and
> XPath 2.0 are large specifications that I imagine could take the developers
> years to implement correctly,anyway it need some guy get the ball rolling, i
> want to be this guy.
>
>
>
> Compared with XSLT 1.0, XSLT 2.0 and XPath 2.0 have some important new
> characteristic.
>
>
>
> New features in XPath 2.0:
>
> 1. Sequences, in XPath2.0 everything is sequences
> 2. For expression,in XPath 2.0,we can use for expression to iterator
> every item in the sequence, compute expression value for each item, at last
> return the sequence result by connect all the expression values.
> 3. Condition expression, XPath 2.0's condition expression can be used to
> compute different value on the basis of the condition's true or false value.
> 4. Limited expression,limited expression in XPath 2.0 can be used to
> judge that whether every item in the sequence satisfy appointed condition,
> its value is always true of false. There are two kinds of limited
> expression: some expression and every expression.
> 5. Datatype,XPath 2.0's datetype is based on XML Schema, it supports all
> the basic built-in datatype,such as xs:integer,xs:string and xs:date ect.
> 6. Date and time, XSLT 1.0 has not date and time datatype, it must use
> string to represent date and time. Due to XPath 2.0 system is based on XML
> schema, so there is date and time data type in XPath 2.0.
> 7. More functions support,XSLT 2.0 specification has more powful
> functions definition.Functions in XPath 2.0 is defined in a special
> recommedation "XQuery 1.0 and XPath 2.0 Functions and Operations", functions
> in this recommendation specification belong to namespace "
> http://www.w3.org/2005/xpath-functions", this namespace is bound with
> prefix "fn".
>
> It includes these serveral types:
>
> * Constructor Functions
> * Functions and Operators on Numerics
> * Functions on Strings
> * Functions on anyURI
> * Functions and Operators on Boolean Values
> * Functions and Operators on Durations, Dates and Times
> * Functions Related to QNames
> * Operators on base64Binary and hexBinary
> * Operators on NOTATION
> * Functions and Operators on Nodes
> * Functions and Operators on Sequences
> * Context Functions
>
> There are also many new features in XSLT 2.0:
>
> 1. Group, basic group syntax,group sort,group-adjacent and
> group-starting-with etc.
> 2. Connotive document node, or we can call it temporary tree
> 3. Element result-document, we can use to generate multi output file in
> XPath 2.0
> 4. Improvement of element value-of
> 5. Char mapping,XSLT 2.0 supply more flexible solution for us to handler
> specific characters in XML such as '<' and '&'
> 6. Custom stylesheet function,in XSLT 2.0, we can use to create our own
> functions in stylesheet
> 7. Other new features.
>
> In order to implement all the XSLT 2.0 specification,it requires some
> moderately basic data structure changes to track Schema types and to handle
> Sequences which aren't simply nodesets,and also,i must implements all the
> new functions defined in XSLT 2.0,fortunately,there is a open source XPath
> 2.0 processor (http://wiki.eclipse.org/PsychoPathXPathProcessor) which is
> at Eclipse.It is already being used by Xerces-J for XSD 1.1 Assertion
> support.Why re-invent the wheel if we can leverage something that already
> exists ? PsychoPath already is XML Schema Aware, leverages Xerces-J(
> http://xerces.apache.org/xerces2-j) and passes about 99.9% of the Xpath
> 2.0 test suite. It is currently undergoing testing against the the official
> W3C Test Suite.
>
>
>
> So, in order to implement all the XSLT 2.0 specification for Xalan, there
> are two steps:
>
> 1. Merge Xalan codes with PsychoPath codes,this will help us a lot,once
> this job is done, Xalan has implemented all the XPath 2.0 features. There
> are some issues to resolve during this merging process,for example:
> * PsychoPath is not "streamy" yet, nor is Xalan, it is a big
> challenge
> * In PsychoPath,type informations is not part of current
> interfaces,i will have to extend or replace the DTM interfaces to carry the
> additional data
> * XSLTC fit in problem. XSLTC runs against the same data model
> interfaces (DTM), and In Theory implementing compilation should just be a
> matter of generating code equivalent to what the interpreter is doing. In
> practice, it's a lot of detail work.
> 2. Implement all the other XSLT 2.0 features which were described before
> for Xalan.
>
> In my plan, i will hold the whole XSLT 2.0 implemention project as a long
> term open source project under Apache, do it step by step, may be as a GSoC
> project,i can only implement a subset of this capability i was thinking of
> working on,at lease, i will finish the following tasks:
>
> 1. Merge Xalan codes with PsychoPath codes, i will do this first, but
> this is not a simple task,may be it will cost me one month or even more to
> merge it correctly.
> 2. Resolve merge problems between Xalan and PsychoPath
> 3. Implement XSLT 2.0 Group feature for Xalan
> 4. Implement XSLT 2.0 temporary tree feature for Xalan
> 5. Implement Element result-document feature for Xalan
>
> If everything goes well and i have enough time,i will do my best to do more
> job. After the summer, i will continue with this project,try to submit my
> codes to Xalan as proposed changes and try to become one of Apache
> committers,this is my dream.And i know this is a huge project,but where
> there is a will there is a success, I love open source, i will do my best to
> improve it through my attemp and ability.
>
>
> Regards
>
> Victor Wang
>
>
>
Re: GSoC project "Implement XSLT 2.0 and XPath 2.0 for Xalan" need your advides
Posted by Jesper Steen Møller <je...@selskabet.org>.
Hello Qi Wang
I think this is a really good idea!
I am one of the developers of the XPath2 engine at the Eclipse WTP project (in fact I don't know much Xalan-J, actually I just contributed two Xalan-J bug fixes which were never picked up)
For the release this summer (Indigo), a new API has been introduced which allows pluggable type models, and allows much better access to the XPath2 engine without using internal packages. Also, the library uses a better structure for separating the parsing and execution of the expression. Also, we will now be JRE 1.4 compatible (sigh).
Lots of improvements you can use there.
However, "PsychoPath" (I hate that name) is still bound to using a Level 3 DOM, and no, we do not have a streamy front end. The internal tree implementation for Xalan would thus have to be wrapped for use with the Eclipse XPath2 engine. But for type-sensitive template handling, this might not be sufficient anyway. So you will face quite a number of challenges!
Also, I hope you can do all this without having to fork the XPath2 engine, since it is also used elsewhere, but we might be able to "semi fork" it and work your changes back into the mainline for the next major release.
As for how to work with the Xalan codebase, I cannot provide guidance on your overall strategy, I think the Xalan-J people can guide you much better there.
Kind regards,
Jesper Steen Møller
On 17/04/2011, at 16.43, Qi Wang wrote:
> Hi all,
>
> All Xalan developer and users, I wan to do something to push XSLT 2.0 implemention job for Xalan, i know this topic was discussed in mail list for many many times in recent years, so many guys are expecting it come true. But due to low activity in Apache Xalan community, no committer to push this thing, it is really very regretful.
>
> These days, i submited "Implement XSLT 2.0 and XPath 2.0 for Xalan" project proposal as an GSoC[1] project. Now, i need your feedbacks to improve the proposal, all the advises, suggestions are welcome :-)
>
> I am not a Xalan committer(alrough i dream to be), but if there is a chance, i want to try my best to so something for XSLT 2.0 implemention job for Xalan, many i can not finish all the job in the summer, but i will make it is available, once wheels start turn, i thing there may be some other guys can work together with me to finish this big project. Hoping all the comunity can work together for the better future of Xalan.
>
> [1] http://socghop.appspot.com
>
> =========Proposal details of "Implement XSLT 2.0 and XPath 2.0 for Xalan"================
>
> Apache Xalan-Java is a powful XSLT processor for XML transforming based on W3C recommendation XSL Transformations (XSLT) Version 1.0 and XML Path Language (XPath) Version 1.0, XSL Transformations (XSLT) Version 2.0 specification was published on 23 January 2007,this new version give us more powful functions, new dat model and serialization etc.
>
>
>
> In my daily work, i use XSLT and XPath to parse XML and change XML document to another format, i did this with Xalan.As we know,Xalan support XSLT version 1.0 and XPath version 1.0 only.But my XML parse job is so complex, and usually, i must use some XPath v2.0 functions to finish my parse job. So, i encountered trouble.
>
>
>
> Then I Google keywords with Xalan and XSLT 2.0,i found many developers hope that Xalan based XSLT 2.0 could become reality besides me. At the same time, i discuss this topic with open source developers in mail list, so many guys are interested in implementing complete XSTL 2.0 specification for Xalan. We discuss this project deeply, and i got many good ideas and advises from the discussion. And also they told me Xalan lost its most active contributors a few years ago due to time demands from Real Jobs, and development slowed down as a result,but they love to see Xalan tackle it.Due to XSLT 2.0 and XPath 2.0 are large specifications that I imagine could take the developers years to implement correctly,anyway it need some guy get the ball rolling, i want to be this guy.
>
>
>
> Compared with XSLT 1.0, XSLT 2.0 and XPath 2.0 have some important new characteristic.
>
>
>
> New features in XPath 2.0:
>
> 1. Sequences, in XPath2.0 everything is sequences
> 2. For expression,in XPath 2.0,we can use for expression to iterator every item in the sequence, compute expression value for each item, at last return the sequence result by connect all the expression values.
> 3. Condition expression, XPath 2.0's condition expression can be used to compute different value on the basis of the condition's true or false value.
> 4. Limited expression,limited expression in XPath 2.0 can be used to judge that whether every item in the sequence satisfy appointed condition, its value is always true of false. There are two kinds of limited expression: some expression and every expression.
> 5. Datatype,XPath 2.0's datetype is based on XML Schema, it supports all the basic built-in datatype,such as xs:integer,xs:string and xs:date ect.
> 6. Date and time, XSLT 1.0 has not date and time datatype, it must use string to represent date and time. Due to XPath 2.0 system is based on XML schema, so there is date and time data type in XPath 2.0.
> 7. More functions support,XSLT 2.0 specification has more powful functions definition.Functions in XPath 2.0 is defined in a special recommedation "XQuery 1.0 and XPath 2.0 Functions and Operations", functions in this recommendation specification belong to namespace "http://www.w3.org/2005/xpath-functions", this namespace is bound with prefix "fn".
>
> It includes these serveral types:
>
> * Constructor Functions
> * Functions and Operators on Numerics
> * Functions on Strings
> * Functions on anyURI
> * Functions and Operators on Boolean Values
> * Functions and Operators on Durations, Dates and Times
> * Functions Related to QNames
> * Operators on base64Binary and hexBinary
> * Operators on NOTATION
> * Functions and Operators on Nodes
> * Functions and Operators on Sequences
> * Context Functions
>
> There are also many new features in XSLT 2.0:
>
> 1. Group, basic group syntax,group sort,group-adjacent and group-starting-with etc.
> 2. Connotive document node, or we can call it temporary tree
> 3. Element result-document, we can use to generate multi output file in XPath 2.0
> 4. Improvement of element value-of
> 5. Char mapping,XSLT 2.0 supply more flexible solution for us to handler specific characters in XML such as '<' and '&'
> 6. Custom stylesheet function,in XSLT 2.0, we can use to create our own functions in stylesheet
> 7. Other new features.
>
> In order to implement all the XSLT 2.0 specification,it requires some moderately basic data structure changes to track Schema types and to handle Sequences which aren't simply nodesets,and also,i must implements all the new functions defined in XSLT 2.0,fortunately,there is a open source XPath 2.0 processor (http://wiki.eclipse.org/PsychoPathXPathProcessor) which is at Eclipse.It is already being used by Xerces-J for XSD 1.1 Assertion support.Why re-invent the wheel if we can leverage something that already exists ? PsychoPath already is XML Schema Aware, leverages Xerces-J(http://xerces.apache.org/xerces2-j) and passes about 99.9% of the Xpath 2.0 test suite. It is currently undergoing testing against the the official W3C Test Suite.
>
>
>
> So, in order to implement all the XSLT 2.0 specification for Xalan, there are two steps:
>
> 1. Merge Xalan codes with PsychoPath codes,this will help us a lot,once this job is done, Xalan has implemented all the XPath 2.0 features. There are some issues to resolve during this merging process,for example:
> * PsychoPath is not "streamy" yet, nor is Xalan, it is a big challenge
> * In PsychoPath,type informations is not part of current interfaces,i will have to extend or replace the DTM interfaces to carry the additional data
> * XSLTC fit in problem. XSLTC runs against the same data model interfaces (DTM), and In Theory implementing compilation should just be a matter of generating code equivalent to what the interpreter is doing. In practice, it's a lot of detail work.
> 2. Implement all the other XSLT 2.0 features which were described before for Xalan.
>
> In my plan, i will hold the whole XSLT 2.0 implemention project as a long term open source project under Apache, do it step by step, may be as a GSoC project,i can only implement a subset of this capability i was thinking of working on,at lease, i will finish the following tasks:
>
> 1. Merge Xalan codes with PsychoPath codes, i will do this first, but this is not a simple task,may be it will cost me one month or even more to merge it correctly.
> 2. Resolve merge problems between Xalan and PsychoPath
> 3. Implement XSLT 2.0 Group feature for Xalan
> 4. Implement XSLT 2.0 temporary tree feature for Xalan
> 5. Implement Element result-document feature for Xalan
>
> If everything goes well and i have enough time,i will do my best to do more job. After the summer, i will continue with this project,try to submit my codes to Xalan as proposed changes and try to become one of Apache committers,this is my dream.And i know this is a huge project,but where there is a will there is a success, I love open source, i will do my best to improve it through my attemp and ability.
>
>
> Regards
>
> Victor Wang