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[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: XPath as a stand-alone programming language
 Jim, Now that I see that there is interest in this, I will consider posting to Bugzilla. Thank you. Dimitre On Wed, Oct 24, 2012 at 8:36 AM, Jim Melton <jim.melton@oracle.com> wrote: > Dimitre, > > Thanks for showing us your work on this. Very interesting, I thought. > > You suggested some new post-3.0 XPath features in your message. A preferred > way to let the XSLT and XML Query Working Groups know of such proposed new > requirements would be to post them on W3C's public Bugzilla instance, using > Product = "XPath / XQuery / XSLT" and Component = "XQuery 3.1 Requirements > and Use Cases". (Note that there is no assurance that there will ever be > another version of XPath, XQuery, or XSLT after the current 3.0 versions > under development, nor that any such future version will be designated > "3.1".) > > You can locate that Bugzilla instance at > https://www.w3.org/Bugs/Public/enter_bug.cgi > > Hope this helps, > Jim > > > At 10/24/2012 07:32 AM, Dimitre Novatchev wrote: >> >> A few months ago I had the pleasure to do "all XPath programming". >> >> I developed the Binary tree data type and the Set data type >> essentially completely in XPath 3.0. >> >> These can be found in my blog, respectively at: >> >> >> >> http://dnovatchev.wordpress.com/2012/01/09/the-binary-search-tree-data-structurehaving-fun-with-xpath-3-0/ >> >> and >> >> >> >> http://dnovatchev.wordpress.com/2012/01/12/the-set-datatype-implemented-in-xpath-3-0/ >> >> At the time this happened accidentally. I don't like to work with >> XQuery, but at that time Saxon's XSLT 3.0 processor didn't fully >> implement higher order functions. Saxon's XQuery 3.0 did, so I >> reluctantly used XQuery 3.0 in my work. Doing so, I planned to move my >> whole code to XSLT 3.0 --whenever Saxon's XSLT 3.0 processor was ready >> for this (and now, in version 9.4 it is). Therefore I essentially >> coded everything as much in pure XPath 3.0 as possible. >> >> >> This experience clearly showed to me that it is possible to use XPath >> 3.0 as a stand-alone programming language. This has many benefits, and >> one of them is that XPath-only code is fully transferrable between >> XSLT and XQuery. >> >> At the end of my latest blog post "Recursion with anonymous (inline) >> functions in XPath 3.0", I list a number of nice features we still >> need in XPath as a programming language, that could be added in a >> future, post-3.0 version: >> >> 1. Stand-alone XPath processors. >> >> 2. Import/include directives for XPath-only files (expression-files). >> >> 3. Separate packaging/compilation of XPath-only programs. >> >> 4. New data structures such as tuples. >> >> 5. Generics ââ¬â parametric data types. >> >> >> Cheers, >> >> Dimitre >> >> >> >> >> On Wed, Oct 24, 2012 at 4:55 AM, Costello, Roger L. <costello@mitre.org> >> wrote: >> > Thanks a lot Michael for the explanation. Fantastic! >> > >> > Below is a summary of my question plus Michael's answer (slightly >> > expanded). >> > >> > The XPath 3.0 specification says this: >> > >> > XPath 3.0 is a composable language >> > >> > What does that mean? >> > >> > It means that every operator and language construct allows any XPath >> > expression to appear as its operand (subject only to operator precedence and >> > data typing constraints). >> > >> > For example, take this expression: >> > >> > 3 + ____ >> > >> > The plus (+) operator has a left-operand, 3. What can the right-operand >> > be? Answer: any XPath expression! Let's use the max() function as the >> > right-operand: >> > >> > 3 + max(___) >> > >> > Now, what can the argument to the max() function be? Answer: any XPath >> > expression! Let's use a for-loop as its argument: >> > >> > 3 + max(for $i in 1 to 10 return ___) >> > >> > Now, what can the return value of the for-loop be? Answer: any XPath >> > expression! Let's use an if-statement: >> > >> > 3 + max(for $i in 1 to 10 return (if ($i gt 5) then $i*3 else $i*2))) >> > >> > The fact that XPath is a composable language is very cool and very >> > powerful. >> > >> > Contrast this with XSLT, which is not fully composable: XPath >> > expressions can be used as operands to XSLT instructions, but not the other >> > way around. Similarly Java has constructs called statements that >> > cannot be nested inside expressions. >> > >> > /Roger >> >> > >> > --~------------------------------------------------------------------ >> > XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list >> > To unsubscribe, go to: http://lists.mulberrytech.com/xsl-list/ >> > or e-mail: <mailto:xsl-list-unsubscribe@lists.mulberrytech.com> >> > --~-- >> > >> >> >> >> -- >> Cheers, >> Dimitre Novatchev >> --------------------------------------- >> Truly great madness cannot be achieved without significant intelligence. >> --------------------------------------- >> To invent, you need a good imagination and a pile of junk >> ------------------------------------- >> Never fight an inanimate object >> ------------------------------------- >> To avoid situations in which you might make mistakes may be the >> biggest mistake of all >> ------------------------------------ >> Quality means doing it right when no one is looking. >> ------------------------------------- >> You've achieved success in your field when you don't know whether what >> you're doing is work or play >> ------------------------------------- >> Facts do not cease to exist because they are ignored. >> ------------------------------------- >> Typing monkeys will write all Shakespeare's works in 200yrs.Will they >> write all patents, too? :) >> ------------------------------------- >> I finally figured out the only reason to be alive is to enjoy it. >> >> _______________________________________________________________________ >> >> XML-DEV is a publicly archived, unmoderated list hosted by OASIS >> to support XML implementation and development. To minimize >> spam in the archives, you must subscribe before posting. >> >> [Un]Subscribe/change address: http://www.oasis-open.org/mlmanage/ >> Or unsubscribe: xml-dev-unsubscribe@lists.xml.org >> subscribe: xml-dev-subscribe@lists.xml.org >> List archive: http://lists.xml.org/archives/xml-dev/ >> List Guidelines: http://www.oasis-open.org/maillists/guidelines.php > > > ======================================================================== > Jim Melton --- Editor of ISO/IEC 9075-* (SQL) Phone: +1.801.942.0144 > Chair, ISO/IEC JTC1/SC32 and W3C XML Query WG Fax : +1.801.942.3345 > Oracle Corporation Oracle Email: jim dot melton at oracle dot com > 1930 Viscounti Drive Alternate email: jim dot melton at acm dot org > Sandy, UT 84093-1063 USA Personal email: SheltieJim at xmission dot com > ======================================================================== > = Facts are facts. But any opinions expressed are the opinions = > = only of myself and may or may not reflect the opinions of anybody = > = else with whom I may or may not have discussed the issues at hand. = > ======================================================================== -- Cheers, Dimitre Novatchev --------------------------------------- Truly great madness cannot be achieved without significant intelligence. --------------------------------------- To invent, you need a good imagination and a pile of junk ------------------------------------- Never fight an inanimate object ------------------------------------- To avoid situations in which you might make mistakes may be the biggest mistake of all ------------------------------------ Quality means doing it right when no one is looking. ------------------------------------- You've achieved success in your field when you don't know whether what you're doing is work or play ------------------------------------- Facts do not cease to exist because they are ignored. ------------------------------------- Typing monkeys will write all Shakespeare's works in 200yrs.Will they write all patents, too? :) ------------------------------------- I finally figured out the only reason to be alive is to enjoy it. 
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