SDPL 2005Notes 5.1: Additional XPath & XSLT1 5.1 Additional features of XPath & XSLT n XPath support for –arithmetics –processing ID/IDREF cross-references

SDPL 2005 Notes 5.1: Additional XPath & XSLT 1

5.1 Additional features of XPath & XSLT5.1 Additional features of XPath & XSLT

XPath support forXPath support for– arithmeticsarithmetics– processing ID/IDREF cross-referencesprocessing ID/IDREF cross-references– manipulation of stringsmanipulation of strings

Generating textGenerating text– for contentfor content– for attribute valuesfor attribute values

Repetition, sorting and conditional processingRepetition, sorting and conditional processing Generating numbersGenerating numbers


XPath: Arithmetical OperationsXPath: Arithmetical Operations

Operators for double-precision (64 bit) floating-Operators for double-precision (64 bit) floating-point arithmeticspoint arithmetics

+, -, *, div, mod+, -, *, div, mod (same as (same as %% in Java)in Java)

Mapping numbers to integers:Mapping numbers to integers:» floor(x) = max{nfloor(x) = max{n n n x} x} » ceiling(x) = min{nceiling(x) = min{n n n x} x} » round(x) = floor(x+0.5) round(x) = floor(x+0.5)

Formatting numbers as strings (example):Formatting numbers as strings (example):» format-number(-1.2534, format-number(-1.2534, ""0.00.0"") = ) = ""-1.3-1.3""


Aggregate FunctionsAggregate Functions

Counting nodes Counting nodes » count(count(node-setnode-set))

– and summing them as numbers and summing them as numbers » sum(sum(node-setnode-set))

Example: Example: – Grade average for the first student in document:Grade average for the first student in document:sum(sum((//student)[1]/course/@grade(//student)[1]/course/@grade)) div div count(count((//student)[1]/course(//student)[1]/course))


Cross-referencingCross-referencing

Function Function idid selects elements by their unique IDselects elements by their unique ID– NBNB: ID attributes need to be declared in DTD: ID attributes need to be declared in DTD

(See an example later)(See an example later)

Examples:Examples:– id('sect:intro')id('sect:intro')

selects the element with unique IDselects the element with unique ID "sect:intro""sect:intro"– id('sect:intro')/para[5]id('sect:intro')/para[5]

selects the fifthselects the fifth parapara child of the above elementchild of the above element– id('sect1 sect2 sect3')id('sect1 sect2 sect3')selects 3 sections selects 3 sections

(if they have the corresponding ID values)(if they have the corresponding ID values)


String manipulationString manipulation

Equality and inequality of strings can be tested Equality and inequality of strings can be tested with operatorswith operators == and and !=!=– "foo" = 'foo'"foo" = 'foo'; ; "foo" != "Foo""foo" != "Foo"

Testing for substrings:Testing for substrings:– starts-with("starts-with("dogdogbert", "bert", "dogdog") = true()") = true()– contains("docontains("dogbegbert", "rt", "gbegbe") = true()") = true()

Concatenation (of two or more strings), Concatenation (of two or more strings), – concat("dog", "bert") = "dogbert"concat("dog", "bert") = "dogbert"


XPath: more string functionsXPath: more string functions

– substring-before("ftp:substring-before("ftp:////a", "a", "////") = ") = substring-before("ftp:substring-before("ftp:///a", "/a", "//") = "ftp:"") = "ftp:"

– substring-after("ftp:substring-after("ftp:///a", "/a", "//")= "/a"")= "/a"– substring(substring(string, start, length?string, start, length?):):

» substring("dogbert", 1, 3) = "dog"substring("dogbert", 1, 3) = "dog"» substring("dogbert", 3) = "gbert"substring("dogbert", 3) = "gbert"

– string-length("dogbert")=7string-length("dogbert")=7– translate(translate(Str, Replaced, ReplacingStr, Replaced, Replacing):):

» translate("translate("doggdoggy","y","dgodgo","Ssi")="Sissy"","Ssi")="Sissy"


Generating TextGenerating Text

The string-value of an expression can be inserted in the The string-value of an expression can be inserted in the result tree by instructionresult tree by instruction

<<xsl:value-ofxsl:value-of select=" select="ExprExpr" />" />– if if ExprExpr evaluates to a node-set, evaluates to a node-set, value of the first nodevalue of the first node in in

document order is useddocument order is used

Consider transforming source elements likeConsider transforming source elements like

<name alias="Bird"><name alias="Bird"><first>Charlie</first><last>Parker</last><first>Charlie</first><last>Parker</last>

</name></name>

to the formto the form

Charlie ("Bird") ParkerCharlie ("Bird") Parker


Computing generated text (2)Computing generated text (2)

This can be specified by template ruleThis can be specified by template rule<xsl:template match="name"><xsl:template match="name"><xls:value-of select="first" /><xls:value-of select="first" />("<xsl:value-of select="@alias" />") ("<xsl:value-of select="@alias" />") <xls:value-of select="last" /> <xls:value-of select="last" /> <xsl:text><xsl:text></xsl:text></xsl:text></xsl:template></xsl:template>

Verbatim text (like the white-space above) can be Verbatim text (like the white-space above) can be inserted usinginserted using xsl:text xsl:text


Attribute value templatesAttribute value templates

The string-value of an expression can be inserted The string-value of an expression can be inserted in an attribute value by surrounding the in an attribute value by surrounding the expression by bracesexpression by braces {{ and and }}

Consider transforming source elementConsider transforming source element<photo><photo>

<file><file>Mary.jpgMary.jpg</file></file> <size width="300"/><size width="300"/>

</photo></photo>into forminto form

<img src="/images/<img src="/images/Mary.jpgMary.jpg" " width="300" />width="300" />


Attribute value templates (2)Attribute value templates (2)

This can be specified by template ruleThis can be specified by template rule<xsl:template match="photo"><xsl:template match="photo">

<img src="/images/<img src="/images/{file}{file}""width="width="{size/@width}{size/@width}" />" />

</xsl:template></xsl:template> ExpressionsExpressions {file}{file} and and {size/@width}{size/@width} are are

evaluated in the context of the current node (the evaluated in the context of the current node (the photophoto element)element)


XSLT: RepetitionXSLT: Repetition

Nodes can be "pulled" from source for Nodes can be "pulled" from source for processing using processing using

<<xsl:xsl:for-eachfor-each select=" select="ExprExpr">">TemplateTemplate

<<xsl:xsl:for-eachfor-each>>

– the template is applied to each of the selected the template is applied to each of the selected nodes (0, 1 or more), each node in turn as the nodes (0, 1 or more), each node in turn as the current()current() node node» in document order, unless sorted using in document order, unless sorted using xsl:sortxsl:sort

instructions (see later)instructions (see later)


Example (of Example (of xsl:xsl:for-eachfor-each))

Consider formatting the below document as HTML:Consider formatting the below document as HTML:<!DOCTYPE document [ <!ATTLIST section id ID #IMPLIED> ]><!DOCTYPE document [ <!ATTLIST section id ID #IMPLIED> ]><document> <title>The Joy of XML</title> <document> <title>The Joy of XML</title> <section id="Intro"><title>Getting Started</title> <section id="Intro"><title>Getting Started</title> <name><first>Helen</first> <last>Brown</last></name> <name><first>Helen</first> <last>Brown</last></name> says that processing XML documents is fun. says that processing XML documents is fun. <name><first>Dave</first> <last>Dobrik</last></name> agrees. <name><first>Dave</first> <last>Dobrik</last></name> agrees. </section> </section> <section><title>Family affairs</title> <section><title>Family affairs</title> <name><first>Bob</first> <last>Brown</last></name> is the <name><first>Bob</first> <last>Brown</last></name> is the husband of <name><first>Helen</first> husband of <name><first>Helen</first> <last>Brown</last></name>. </section> <last>Brown</last></name>. </section> <section><title>Finishing Up</title> <section><title>Finishing Up</title> As we discussed in <title-ref idref="Intro" />, processing XML As we discussed in <title-ref idref="Intro" />, processing XML documents is fun. </section></document>documents is fun. </section></document>


Example: Table of contentsExample: Table of contents

A table of contents can be formed of section titles:A table of contents can be formed of section titles:<xsl:template match="/"><xsl:template match="/"><HTML><HEAD> <TITLE><xsl:value-of <HTML><HEAD> <TITLE><xsl:value-of

select="document/title"/></TITLE></HEAD> select="document/title"/></TITLE></HEAD> <BODY> <BODY> <H2>Table of Contents</H2> <H2>Table of Contents</H2> <OL>  <OL>  <xsl:for-each select="//section/title"><xsl:for-each select="//section/title"> <LI><xsl:apply-templates /></LI> <LI><xsl:apply-templates /></LI> </xsl:for-each></xsl:for-each> </OL>  </OL>  <xsl:apply-templates select=“document/section"/> <xsl:apply-templates select=“document/section"/> </BODY> </HTML> </BODY> </HTML></xsl:template></xsl:template>


Example (cont; Cross references)Example (cont; Cross references)

Cross references (to sections) can also be processed Cross references (to sections) can also be processed using using xsl:for-each: xsl:for-each: <xsl:template match="title-ref"> <xsl:template match="title-ref"> <xsl:for-each select="id(@idref)"><xsl:for-each select="id(@idref)"> Section (<xsl:value-of Section (<xsl:value-of

select="substring(title, 1, 8)" />...)select="substring(title, 1, 8)" />...) </xsl:for-each></xsl:for-each></xsl:template></xsl:template>

With this rule the source fragment With this rule the source fragment As we discussed in <title-ref idref="Intro"/>As we discussed in <title-ref idref="Intro"/>

becomesbecomesAs we discussed in Section (Getting …)As we discussed in Section (Getting …)


XSLT SortingXSLT Sorting

A sorted order for the processing of nodes with A sorted order for the processing of nodes with xsl:for-eachxsl:for-each and and xls:apply-templatesxls:apply-templates can be specified by can be specified by <<xsl:sortxsl:sort/>/>

controlled by attributes of controlled by attributes of xsl:sortxsl:sort like like– selectselect: expression for the sort key: expression for the sort key– data-typedata-type: : "text" "text" (default) or(default) or "number" "number" – orderorder: : "ascending""ascending" (default) (default)

or or "descending""descending" The first The first xsl:sortxsl:sort specifies the primary sort key, specifies the primary sort key,

the second one the secondary sort key, and so on.the second one the secondary sort key, and so on.


Example (cont; Sorted index of names)Example (cont; Sorted index of names)

All names can be collected in a last-name-first-name order All names can be collected in a last-name-first-name order using the below templateusing the below template<H2>Index</H2> <UL><H2>Index</H2> <UL> <xsl:for-each select="//name"> <xsl:for-each select="//name"> < <xsl:sortxsl:sort select="last" /> select="last" /> < <xsl:sortxsl:sort select="first" /> select="first" /> <LI><xsl:value-of select="last" <LI><xsl:value-of select="last" />, <xsl:value-of select="first"/></LI> />, <xsl:value-of select="first"/></LI> </xsl:for-each> </xsl:for-each></UL></UL>

This creates an UL list with itemsThis creates an UL list with items<LI>Brown, Bob</LI> <LI>Brown, Bob</LI> <LI>Brown, Helen</LI> <LI>Brown, Helen</LI> <LI>Brown, Helen</LI> <LI>Brown, Helen</LI> <LI>Dobrik, Dave</LI><LI>Dobrik, Dave</LI>


What about duplicates?What about duplicates?

Is it possible to eliminate duplicate values like Is it possible to eliminate duplicate values like <LI>Brown, Helen</LI> <LI>Brown, Helen</LI> <LI>Brown, Helen</LI> <LI>Brown, Helen</LI> ??

Yes (but not that straightforward)Yes (but not that straightforward) Using conditional instructionsUsing conditional instructions

– See nextSee next


Conditional processingConditional processing

A template can be instantiated or ignored based A template can be instantiated or ignored based on the value of a on the value of a testtest Boolean expression, usingBoolean expression, using

<<xsl:ifxsl:if test=" test="ExpressionExpression">">TemplateTemplate

</</xsl:ifxsl:if> > Example: a comma-separated list of names:Example: a comma-separated list of names:<xsl:template match="namelist/name"><xsl:template match="namelist/name"> <xsl:apply-templates/> <xsl:apply-templates/> < <xsl:ifxsl:if test="position() < last()" test="position() < last()" > >, , </</xsl:ifxsl:if>></xsl:template></xsl:template>


Conditional processing (2)Conditional processing (2)

Also a case-like construct (Also a case-like construct ( switchswitch in Java): in Java): <xsl:choose><xsl:choose>

instantiated: -->

<xsl:when <xsl:when test="test="ExprExpr11"">> … … </xsl:when></xsl:when>

<xsl:when <xsl:when test="test="ExprExpr22"">> … … </xsl:when></xsl:when>… …

' is instantiated: --><xsl:otherwise><xsl:otherwise> … … </xsl:otherwise></xsl:otherwise>

</xsl:choose></xsl:choose>


Example (cont; Eliminating duplicate names)Example (cont; Eliminating duplicate names)

No access to other nodes (except No access to other nodes (except current()current()) in the list of ) in the list of xsl:for-eachxsl:for-each– But can refer to other nodes in the source treeBut can refer to other nodes in the source tree– Process just the first one of duplicate Process just the first one of duplicate namenames: s: <xsl:for-each select="//name"><xsl:for-each select="//name"> <xsl:sort select="last"/><xsl:sort select="last"/><xsl:sort select="first" /> <xsl:sort select="first" /> <xsl:if test="not(<xsl:if test="not(

preceding::name[first=current()/first preceding::name[first=current()/first and last=current()/last] )">and last=current()/last] )">

<LI><xsl:value-of select="last" <LI><xsl:value-of select="last" />, <xsl:value-of select="first"/></LI> />, <xsl:value-of select="first"/></LI></xsl:if></xsl:if></xsl:for-each></xsl:for-each>


Generating NumbersGenerating Numbers

Formatted numbers can be inserted in the result Formatted numbers can be inserted in the result tree by element tree by element xsl:numberxsl:number – number can be specified by attributenumber can be specified by attribute value="value="ExprExpr""– otherwise the number generated by the position of the otherwise the number generated by the position of the

current node in the source treecurrent node in the source tree

We’ll consider typical cases through examplesWe’ll consider typical cases through examples– The complete rules of the Spec are rather complexThe complete rules of the Spec are rather complex

Example 1: Numbering list itemsExample 1: Numbering list items


Generating numbers: Example 1Generating numbers: Example 1

<xsl:template match="ol/item"><xsl:template match="ol/item">  (items) --> <<xsl:numberxsl:number format="1. "/> format="1. "/> <xsl:apply-templates/> <xsl:apply-templates/><xsl:template><xsl:template>

itemitem itemitem itemitem

olol

apricotapricot bananabanana coconutcoconut

1.1. 2.2. 3.3.

apricotapricotbananabananacoconutcoconut



Hierarchical numbering (1, 1.1, 1.1.1, 1.1.2, …) Hierarchical numbering (1, 1.1, 1.1.1, 1.1.2, …) for titles of chapters, titles of their sections, and for titles of chapters, titles of their sections, and titles of subsections:titles of subsections:<xsl:template match="title"><xsl:template match="title"> <<xsl:numberxsl:number level="multiple" level="multiple" count="chap|sect|subsect" count="chap|sect|subsect" format="1.1 "/> format="1.1 "/> <xsl:apply-templates/> <xsl:apply-templates/></xsl:template></xsl:template>



11 1.11.1 1.1.11.1.1 22

chapchap

SweetsSweets

titletitle

titletitle

BerriesBerries

sectsect

subsectsubsect

CherryCherry

titletitle

chapchap

titletitle

VegetablesVegetables

. . .. . .

. . .. . .

SweetsSweets BerriesBerries CherryCherry VegetablesVegetables


Example 2: VariationExample 2: Variation

As above, but number titles within appendices As above, but number titles within appendices with A, A.1, A.1.1, B.1 etc:with A, A.1, A.1.1, B.1 etc:

<xsl:template match="appendix//title"><xsl:template match="appendix//title"> <<xsl:numberxsl:number level="multiple" level="multiple" count="appendix|sect|subsect" count="appendix|sect|subsect" format="A.1 "/> format="A.1 "/> <xsl:apply-templates/> <xsl:apply-templates/></xsl:template></xsl:template>


Example 2: VariationExample 2: Variation

AA A.1A.1 A.1.1A.1.1 BB

appendixappendix

SweetsSweets

titletitle

titletitle

BerriesBerries

sectsect

subsectsubsect

CherryCherry

titletitle

titletitle

VegetablesVegetables

. . .. . .

. . .. . .

SweetsSweets BerriesBerries CherryCherry VegetablesVegetables

appendixappendix



Sequential numbering of Sequential numbering of notenotes s withinwithin chapchaptersters::(more precisely: starting anew at the start of any chapter)(more precisely: starting anew at the start of any chapter)

<xsl:template match="note"><xsl:template match="note"> <<xsl:numberxsl:number level="any" level="any" from="chap" from="chap" format="(1) "/> format="(1) "/> <xsl:apply-templates/> <xsl:apply-templates/></xsl:template></xsl:template>


Ex 3: Sequential numbering Ex 3: Sequential numbering fromfrom chaps chaps

chapchap

Yes!Yes!

notenote

notenote

No!No!

sectsectPerhaps?Perhaps?

notenotenotenote

OKOK

. . .. . .

. . .. . .(1)(1) (2)(2) (3)(3) (1)(1)

Yes!Yes! No!No! Perhaps?Perhaps? OKOK

chapchap

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SDPL 2005Notes 5.1: Additional XPath & XSLT1 5.1 Additional features of XPath & XSLT n XPath support for –arithmetics –processing ID/IDREF cross-references