Whats New in XSLT 2.0

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Whats New in XSLT 2.0?

• Steve Heckler
• Accelebrate
• http//www.accelebrate.com
• steveheckler_at_accelebrate.com

[phone] phone [phone] fax
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Acknowledgement

• Bob DuCharme (bob_at_snee.com), who generously gave
  me permission to use code from his XSLT 2.0
  article series on xml.com (published by OReilly
  Associates)
• Bob is author of XSLT Quickly by Manning (see
  http//www.snee.com/bob/xsltquickly)
• 1,000 new copies are being printed in February,
  so be persistent if you look for it!
• Bobs articles are all linked from
  http//www.xml.com/pub/au/42

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What Well Cover

• Role of XSLT
• XSLT 2.0 status/overview
• New features of XSLT 2.0
• Grouping
• Functions
• Data type checking
• String handling regular expressions
• Transclusion
• Temporary Trees
• Conclusion

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Role of XSLT

• XSLT allows you to transform XML documents
• The results can be
• Same XML document type with filtered data
• Another XML document type
• Other text formats
• HTML
• Delimited text
• etc., etc.
• Within XSLT stylesheets, XPath is the language
  used to select the elements to operate on

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XSLT inputs and outputs
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XSLT 2.0 Status (as of late Jan 2004)

• XSLT 2.0 and XPath 2.0 are still working drafts
• Latest drafts of both were released on 12
  November 2003.
• Final Recommendation status is anticipated (but
  not guaranteed) for this year
• Only Saxon (http//saxon.sourceforge.net)
  implements XSLT 2.0
• Saxon 7.8 runs on J2SE 1.4 and later
• Other implementations are expected to rapidly
  emerge once XSLT 2.0 and XPath 2.0 achieve Final
  Recommendation status

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Grouping

• XSLT 1.0 allowed sorting, but not SQL-style
  grouping
• ltxslfor-each-group /gt iterates through a set of
  groups. Attributes
• select XPath expression for which elements to
  select
• group-by Node by which to group the results
• group-adjacent Leaves elements in their original
  order and groups elements with the same key value
  together
• group-starting-with Specifies a node that will
  be treated as the beginning of a new group
• group-ending-with Specifies a node that will be
  treated as the end of the group

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Grouping

• Functions to know
• current-grouping-key() returns the current value
  of the grouping key shared by members of the
  group
• current-group() returns a reference to the
  current group
• The code Ive shown and a related article are
  available at http//www.xml.com/pub/a/2003/11/05/t
  r.html

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Functions

• XSLT is really a programming language, but in
  version 1.0 lacked the ability to define new
  functions
• XSLT 2.0 rectifies this
• You can define new functions
• These functions can take 0 or more parameters
• These functions can return a value

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Functions

• ltxslfunctiongtlt/xslfunctiongt wraps the
  function. Attributes
• name The name of the function
• as Data type returned by the function (as an
  XML Schema data type)
• override Whether this function should override
  previous definitions with the same name and arity
  (number of xslparam elements in the function
  definition)

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Functions

• Content of the function
• 0 or more ltxslparam /gt elements that define
  incoming parameters
• Code to execute final value can be returned via
  ltxslvalue-of /gt, ltxslsequence /gt, or another
  expression
• The code Ive shown and a related article are
  available at http//www.xml.com/pub/a/2003/09/03/t
  rxml.html

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Data Type Checking

• XSLT 2.0 supports the XML Schema data typing
  system
• XPath 2.0s castable as keyword tests whether a
  value can be converted to a certain type and
  returns a boolean with the result
• The code Ive shown and a related article are
  available at http//www.xml.com/pub/a/2003/10/01/t
  r.html

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String Handling

• String comparison
• Strings can now be compared (in ASCII order) via
  the compare() function, which takes 2 strings as
  parameters
• -1 means the string on the left is greater
• 0 means the strings are equal
• 1 means the string on the right is greater

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String Handling

• Find/Replace
• translate(), in XSLT 1.0, only let you replace
  individual characters with other characters
• Similar to tr// in Perl
• replace(), introduced in XSLT 2.0, lets you
  replace strings of characters. Parameters
• The string to search (required)
• The substring to search for (required)
• The string with which this substring should be
  replaced (required)
• Flags (optional)
• m multiline match mode
• i ignore case

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String Handling

• Concatenation
• string-join() joins a sequence of strings into a
  single string. Arguments
• The sequence whose elements are to be joined
• The delimiting character(s) that currently
  separate the elements in the sequence
• tokenize() does the reverse, splitting a string
  into a sequence. Parameters
• The string to tokenize
• The string or pattern to use as a delimiter
  between tokens

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String Handling

• The code from this section and related articles
  can be found at
• http//www.xml.com/pub/a/2003/05/07/tr.html
• http//www.xml.com/pub/a/2003/08/06/tr.html

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Regular Expressions

• Regular expressions, now supported by most modern
  programming languages, allow you to search for
  patterns within strings
• They can be used in XML Schemas to pattern
  restrict elements and attributes whose type is
  xsstring

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Regular Expressions

• Within XSLT 2.0, there are three key functions
  that use regular expressions
• tokenize() discussed earlier Lets you split a
  string into pieces at each point where a
  delimiter or pattern occurs
• matches() Returns a boolean with whether the
  string in the first argument contains the pattern
  in the second argument
• replace() Replaces the string or pattern in the
  first argument with the string in the second
  argument

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Regular Expressions

• Retrieving back references
• When a string matches a pattern, you can retrieve
  the pieces of the string that matched specific
  sections of the pattern
• Each of these sections should be wrapped in ()
  within the pattern
• From left to right, the values of these sections
  will be assigned to 1, 2, 3, etc.

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Basic Frequency Operators

• ? 0 or 1
• 0 or more
• 1 or more
• So, 3 would match 3, 33, and 3333, but not 45 or
  678.

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Wildcard Operator .

• . matches any non-newline character
• Unless multiline mode has been turned on for the
  pattern
• Examples
• A. would match a capital A followed by any
  character.
• A. would match a capital A followed by one or
  more non-newline characters
• \.htm.? would match ".htm" followed by an
  optional non-newline character
• The backslash is used to escape characters that
  have reserved meanings in regular expressions

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Enclosing Alternatives with

• The square brackets allow you to specify a list
  of alternate values. Used in conjunction with
  the operator, you can even specify character
  ranges.
• Cc Capital or lowercase c
• A-Z Any capital letter A through Z
• A-Za-z Any capital or lowercase letter
• 0-9 Any digit 0 through 9
• A-Za-z0-9 Any letter or digit

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Controlling ExpressionFrequency with

• The operators allow you to control the
  frequency of the preceding expression. The
  expression takes one of these two forms
• precise_number_of_occurrences
• min_occurrences, max_occurences

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Controlling ExpressionFrequency with

• A-Za-z3
• A capital letter followed by 3 lowercase letters
• A-Za-z2,4
• A capital letter followed by at least 2 but not
  more than 4 lowercase letters
• 0-94
• 4 digits
• .3,8\..3
• 3 to 8 non-newline characters, followed by a dot
  and 3 non-newline characters (presuming multiline
  match mode is off)

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Convenience Expressions

• \d
• Any digit
• \D
• Any non-digit
• \s
• Any whitespace character (such as a space or tab)

• \S
• Any character other than a whitespace character
• \w
• Any number or letter
• \W
• Any character other than a number or letter

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Regular ExpressionsSample XML Code

• ltaddressesgt
• ltaddressgt
• ltnamegtRichard Muttlt/namegt
• ltaddrLine1gt30 Main St.lt/addrLine1gt
• ltaddrLine2gtNew Haven, CT 06460lt/addrLine2gt
• lt/addressgt
• ltaddressgt
• ltnamegtNanker Phelgelt/namegt
• ltaddrLine1gt1432 Broad St.lt/addrLine1gt
• ltaddrLine2gtPhoenix Arizonalt/addrLine2gt
• lt/addressgt
• ltaddressgt
• ltnamegtBilly Shearslt/namegt
• ltaddrLine1gt1 Grand View Crestlt/addrLine1gt
• ltaddrLine2gt Lansing, MI 22934-2234lt/addrLin
  e2gt
• lt/addressgt
• lt/addressesgt

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Regular Expressions SampleXSLT Code

• ltxsltemplate match"addrLine2"gt
• ltxslvariable name"elValue" select"."/gt
• ltxslanalyze-string select"elValue"
• regex"\s(.)\s,\s(A-Z2)\s(\d5
  (\-\d4)?)\s"gt
• ltxslmatching-substringgt
• ltcitygtltxslvalue-of select"regex-group(1)"/
  gtlt/citygt
• ltstategtltxslvalue-of select"regex-group(2)"
  /gtlt/stategt
• ltzipgtltxslvalue-of select"regex-group(3)"/gt
  lt/zipgt
• lt/xslmatching-substringgt

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Regular Expressions SampleXSLT Code

• ltxslnon-matching-substringgt
• ltaddrLine2gt
• ltxslvalue-of select"elValue"/gt
• lt/addrLine2gt
• lt/xslnon-matching-substringgt
• lt/xslanalyze-stringgt
• lt/xsltemplategt

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Regular Expression XSLT Tags

• To analyze a string, create an ltxslanalyze-string
  /gt element. Attributes
• select The string to analyze
• regex The pattern to which the string is
  compared

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Regular Expression XSLT Tags

• ltxslmatching-substring /gt allows you to retrieve
  and display substrings that match parenthesized
  expressions within the pattern
• Within this block, you can use the regex-group()
  function to retrieve the value of a parenthesized
  group
• This function takes a single argument, the
  backreference number

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Regular Expression XSLT Tags

• ltxslnon-matching-substring /gt contains code that
  operates on the portions of the string that did
  not match the parenthesized expressions in the
  pattern

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Resource Used for Regular Expressions in XSLT 2.0

• Bob DuCharmes article at http//www.xml.com/pub/a
  /2003/06/04/tr.html was the source for the code
  shown

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Transclusion

• Transclusion is the act of dynamically including
  data from another resource into the current
  resource
• Analogous to a server-side include in Web
  development
• Sample code using the document() function
• ltchapter xslversion"2.0"
• xmlnsxsl"http//www.w3.org/1999/XSL/Transf
  orm"gt
• lttitlegtdoc1.xmllt/titlegt
• ltpgtFirst paragraphlt/pgt
• ltxslcopy-of select"document('doc2.xml')/doc/p_at_
  id'p2'"/gt
• ltpgtLast paragraphlt/pgt
• lt/chaptergt

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Transclusion

• This code and a related article can be found at
  http//www.xml.com/pub/a/2003/07/09/xslt.html

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Temporary Trees

• In XSLT 2.0, xslvariable, xslparam, and
  xslwith-param can now be used to store temporary
  XML fragments. Example
• ltxslvariable name"genData"gt
• ltssheetMetadatagt
• ltfilenamegtprepdata.xsllt/filenamegt
• ltauthorgtBDlt/authorgt
• ltreleaseHistgt
• ltversion date"2003-10-12T1452"
  fileSize"1543"gt1.2lt/versiongt
• ltversion date"2003-09-11T1012"
  fileSize"1322"gt1.1lt/versiongt
• ltversion date"2003-07-24T0803"
  fileSize"1134"gt1.0lt/versiongt
• lt/releaseHistgt
• lt/ssheetMetadatagt
• lt/xslvariablegt

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Temporary Trees

• These variables can then be used in XPath
  expressions
• ltxsltemplate match"/"gt
• ltxslcall-template name"outputMetadata"gt
• ltxslwith-param name"revData"
  select"genData"/gt
• lt/xslcall-templategt
• ltxslapply-templates/gt
• lt/xsltemplategt

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Temporary Trees

• ltxsltemplate name"outputMetadata"gt
• ltxslparam name"revData"/gt
• ltxslcommentgt
• File name ltxslvalue-of select"revData/ss
  heetMetadata/filename"/gt
• Revision History
• ltxslfor-each select"revData/ssheetMetadat
  a/releaseHist/version"gt
• release ltxslvalue-of select"."/gt
• ltxsltextgt lt/xsltextgtltxslvalue-of
  select"_at_date"/gt
• lt/xslfor-eachgt
• average file size ltxslvalue-of
  select"myavgFileSize(revData)"/gt
• lt/xslcommentgt
• lt/xsltemplategt

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Temporary Trees

• ltxslfunction name"myavgFileSize"gt
• ltxslparam name"fileData"/gt
• ltxslvalue-of
• select"avg(fileData/ssheetMetadata/releas
  eHist/version/_at_fileSize)"/gt
• lt/xslfunctiongt
• ltxsltemplate match"_at_node()"gt
• ltxslcopygt
• ltxslapply-templates select"_at_node()"/gt
• lt/xslcopygt
• lt/xsltemplategt

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Temporary Trees

• The code for this section and a related article
  covering temporary trees in more detail can be
  found at http//www.xml.com/pub/a/2003/12/03/tr.ht
  ml

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Recommended Resources

• xml.com A fabulous resource for all things XML,
  including XSLT
• The XPath 2.0 working draft http//www.w3.org/TR/
  xpath20/
• The XSLT 2.0 working draft http//www.w3.org/TR/x
  path20/
• Saxon http//saxon.sourceforge.net/

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Thanks for Joining Me!

• Please email questions to steveheckler_at_accelebrate
  .com
• Please visit http//www.accelebrate.com/present/
  for a copy of this presentation and links to the
  source code
• Good luck with XSLT 2.0! ?