XML Mini-Tutorial

Michael I. SchwartzbachCopyright © 2000 BRICS, University of Aarhus

http://www.brics.dk/~mis/ITU/XML/

What is XML?HTML vs. XMLA conceptual view of XMLA concrete view of XMLApplications of XMLXML technologiesNamespacesThe recipe exampleSchema languagesA schema for recipesXLink, XPointer, and XPathPointing at recipesXML-QLQuerying the recipesXSLTA style sheet for recipes

Exercises

XML Mini-Tutorial

http://www.brics.dk/~mis/ITU/XML/ [18/09/2000 14:24:26]

HTML, JavaScript, and XMLMini-Tutorials

Michael I. SchwartzbachCopyright © 2000 BRICS, University of Aarhus

http://www.brics.dk/~mis/ITU/

These mini-tutorials are created as part of the course Internet Programming at the IT-University ofCopenhagen.

HTML (PDF)JavaScript (PDF)XML (PDF)

HTML, JavaScript, and XML Mini-Tutorials

http://www.brics.dk/~mis/ITU/XML/info.html [18/09/2000 14:24:28]

What is XML?XML is a framework for defining markup languages:

there is no fixed collection of markup tags;●

each XML language is targeted at different application domains;●

the languages will share many features;●

there is a common set of tools for processing such languages.●

XML is not a replacement for HTML:HTML should ideally be just another XML language;●

in fact, XHTML is just that;●

XHTML is a (very popular) XML language for hypertext markup.●

XML is designed to:seperate syntax from semantics;●

support internationalization (Unicode) and platform independence;●

be the future of structured information, including databases.●

XML: what is it?

http://www.brics.dk/~mis/ITU/XML/whatis.html [18/09/2000 14:24:29]

HTML vs. XMLConsider the following recipe collection published in HTML:

<h1>Rhubarb Cobbler</h1><h2>Maggie.Herrick@bbs.mhv.net</h2><h3>Wed, 14 Jun 95</h3>

Rhubarb Cobbler made with bananas as the main sweetener. It was delicious. Basicly it was

<table> <tr><td> 2 1/2 cups <td> diced rhubarb (blanched with boilingwater, drain) <tr><td> 2 tablespoons <td> sugar <tr><td> 2 <td> fairly ripe bananas sliced 1/4" round <tr><td> 1/4 teaspoon <td> cinnamon <tr><td> dash of <td> nutmeg </table>

Combine all and use as cobbler, pie, or crisp.

Related recipes: <a href="#GardenQuiche">Garden Quiche</a>

There are many problems with this approach:

the semantics is encoded into text formatting tags;●

there is no means of checking that a recipe is encoded correctly;●

it is difficult to change the layout of recipes (CSS is not enough).●

It would be much better to invent a special recipe markup language:

<recipe id="117" category="dessert"> <title>Rhubarb Cobbler</title> <author><email>Maggie.Herrick@bbs.mhv.net</email></author> <date>Wed, 14 Jun 95</date>

<description> Rhubarb Cobbler made with bananas as the main sweetener. It was delicious. </description>

<ingredients> ...

XML vs. HTML

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</ingredients>

<preparation> Combine all and use as cobbler, pie, or crisp. </preparation>

<related url="#GardenQuiche">Garden Quiche</related></recipe>

This example illustrates:

the markup tags are chosen purely for logical structure;●

this is just one choice of markup detail level;●

we need a kind of "grammar" for XML recipe collections;●

we need a stylesheet to define presentation semantics.●

XML vs. HTML

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A conceptual view of XMLAn XML document is a labeled tree.

a leaf node ischaracter data (a text string) - the actual data,❍

a processing instruction - annotations for various processors, typically in documentheader,

❍

a comment - never any semantics attached,❍

an entity declaration - simple macros.❍

●

an internal node is an element, which is labeled witha name, and❍

a set of attributes, each consisting of a name and a value.❍

●

Often, comments and entity declarations are not explicitly represented in the tree.

XML: a conceptual view

http://www.brics.dk/~mis/ITU/XML/conceptual.html [18/09/2000 14:24:31]

A concrete view of XMLAn XML document is a (Unicode) text with markup tags and other meta-information.

Markup tags denote elements:

...<foo attr="val" ...>...</foo>... | | | | | | | a matching element end tag | | the contents of the element | an attribute with name attr and value val, values enclosed by ' or " an element start tag with name foo

There is a short-hand notation for empty elements: ...<foo attr="val".../>...

Note: XML is case sensitive!!

An XML document must be well-formed:start and end tags must match;●

element tags must be properly nested;●

and some more subtle syntactical requirements.●

Special characters can be escaped using Unicode character references:&#38; yields &;●

&#60; and &lt; both yield <.●

CDATA Sections are an alternative to escaping many characters:<![CDATA[<greeting>Hello, world!</greeting>]]>●

The strange syntax is a legacy from SGML...

The following service checks well-formedness of an XML document (given a full URL):

XML: a concrete view

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Applications of XMLThere are already hundreds of serious applications of XML.

XHTML

W3C's XMLization of HTML 4.0. Example XHTML document:

<?xml version="1.0" encoding="UTF-8"?> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"> <head><title>Hello world!</title></head> <body><p>foobar</p></body> </html>

CML

Chemical Markup Language. Example CML document snippet:

<molecule id="METHANOL"> <atomArray> <stringArray builtin="elementType">C O H H H H</stringArray> <floatArray builtin="x3" units="pm"> -0.748 0.558 -1.293 -1.263 -0.699 0.716 </floatArray> </atomArray> </molecule>

WML

Wireless Markup Language for WAP services:

<?xml version="1.0"?> <wml> <card id="Card1" title="Wap-UK.com"> <p> Hello World </p> </card> </wml>

There is a long list of many other XML applications.

XML: applications

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XML technologiesJust a notation for trees is not enough:

the real force of XML is generic languages and tools!●

The XML vision offers:namespaces

- to avoid name clashes when a document uses several "sub-languages";schemas

- grammars to define classes of documents;linking between documents

- a generalization of HTML anchors and links;addressing parts of documents

- it is not enough that only the author can place anchors;transformation

- conversion from one document class to another;querying

- extraction of information.The site www.xmlsoftware.com has a comprehensive list of available XML tools.

XML: technologies

http://www.brics.dk/~mis/ITU/XML/tech.html [18/09/2000 14:24:34]

NamespacesConsider an XML language WidgetML which uses XHTML as a sublanguage for help messages:

<widget type="gadget"> <head size="medium"/> <big><subwidget ref="gizmo"/></big> <info> <head> <title>Description of gadget</title> </head> <body> <h1>Gadget</h1> A gadget contains a big gizmo </body> </info></widget>

We have some problems here:

the meaning of head and big depends on the context;●

this complicates things for processors and might even cause ambiguities;●

the root of the problem is: one common name-space.●

The solution is to introduce explicit namespace declarations:

<widget xmlns="http://www.widget.org" xmlns:xhtml="http://www.w3.org/TR/xhtml1" type="gadget"> <head size="medium"/> <big><subwidget ref="gizmo"/></big> <info> <xhtml:head> <xhtml:title>Description of gadget</xhtml:title> </xhtml:head> <xhtml:body> <xhtml:h1>Gadget</xhtml:h1> A gadget contains a big gizmo </xhtml:body> </info></widget>

Do not be confused by the use of URI for namespaces:

they are not supposed to point to anything;●

it is simply the cheapest way of getting unqiue names;●

XML: namespaces

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we rely on existing organizations that control domain names.●

All XML technologies (are supposed to) respect namespaces.

XML: namespaces

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The recipe exampleConsider the following raw data describing some (Danish) recipes:

citrontærte;●

farsbrød;●

hornfisk;●

islagkage;●

laksemousse;●

nougattoppe;●

rabarberdessert;●

smørrebrød.●

We can represent this collection as an XML document.

XML: recipe example

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Schema languagesThe syntax of a new XML language must be formalized:

this is similar to the formal syntax of a programming language;●

however, usual context-free grammars are not expressive enough;●

XML languages are described using schemas.●

A modern schema language:is itself an XML language (and can be used to describe itself);●

imposes constraints on the contents of elements;●

is context-sensitive and very fine-grained;●

can be processed efficiently.●

A schema processor:checks that an application document satisfies the schema;●

such a document is called valid.●

XML: schemas

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A schema for recipesThe following is a complete schema for the recipe example, written in the DSD schema language:

<?xml version="1.0" encoding="UTF-8"?><?dsd URI="http://www.brics.dk/DSD/dsd.dsd"?>

<DSD IDRef="opskriftsamling" DSDVersion="1.0"> <ElementDef ID="opskriftsamling"> <Optional><Element IDRef="beskrivelse"/></Optional> <ZeroOrMore><Element IDRef="opskrift"/></ZeroOrMore> </ElementDef>

<ElementDef ID="beskrivelse"> <Content IDRef="hvadsomhelst"/> </ElementDef>

<ContentDef ID="hvadsomhelst"> <ZeroOrMore> <Union> <StringType/><AnyElement/> </Union> </ZeroOrMore> </ContentDef>

<ElementDef ID="titel"> <Content IDRef="hvadsomhelst"/> </ElementDef>

<ElementDef ID="opskrift"> <AttributeDecl Name="kvantitet" Optional="no"/> <AttributeDecl Name="tid" Optional="yes"/> <Sequence> <Element IDRef="titel"/> <Content IDRef="indhold"/> <Optional> <Element Name="garniture"> <Content IDRef="hvadsomhelst"/> </Element> </Optional> <Optional> <Element Name="servering"> <Content IDRef="hvadsomhelst"/>

XML: schema for recipes

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</Element> </Optional> <Optional> <Element Name="tips"> <Content IDRef="hvadsomhelst"/> </Element> </Optional> <Element Name="energi"> <AttributeDecl Name="kjoule" Optional="no"/> <AttributeDecl Name="fedt" Optional="no"> <StringType IDRef="tal"/> </AttributeDecl> <AttributeDecl Name="kulhydrat" Optional="no"> <StringType IDRef="tal"/> </AttributeDecl> <AttributeDecl Name="protein" Optional="no"> <StringType IDRef="tal"/> </AttributeDecl> <AttributeDecl Name="alkohol" Optional="yes"> <StringType IDRef="tal"/> </AttributeDecl> </Element> </Sequence> </ElementDef>

<ContentDef ID="indhold"> <Sequence> <OneOrMore> <Element IDRef="ingrediens"/> </OneOrMore> <Element Name="tilberedning"> <Content IDRef="hvadsomhelst"/> </Element> </Sequence> </ContentDef>

<ElementDef ID="ingrediens"> <AttributeDecl Name="navn" Optional="no"/> <AttributeDecl Name="antal" Optional="yes"> <Union> <String Value="*"/> <StringType IDRef="tal"/> </Union> </AttributeDecl> <AttributeDecl Name="enhed" Optional="yes"/> <If><Attribute Name="antal"/> <Then> <Empty/> </Then>

XML: schema for recipes

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<Else> <Not><Attribute Name="enhed"/></Not> <Content IDRef="indhold"/> </Else> </If> </ElementDef>

<StringTypeDef ID="cifre"> <OneOrMore> <CharRange Start="0" End="9"/> </OneOrMore> </StringTypeDef>

<StringTypeDef ID="tal"> <Sequence> <StringType IDRef="cifre"/> <Optional> <Sequence> <String Value=","/> <StringType IDRef="cifre"/> </Sequence> </Optional> </Sequence> </StringTypeDef></DSD>

XML: schema for recipes

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XML: XLink, XPointer, and XPathXLink, XPointer, and XPath are three related mechanisms:

they generalize the link mechanisms from HTML;●

XPath points from without to a set of nodes in an XML document;●

XPointer uses XPath to directly generalize HTML links;●

XLink uses XPointer to vastly generalize HTML links.●

HTML links are just too simple:

an anchor must be placed at every link destination (problem with read-only documents)- we want to express relative locations;

●

the link definition must be at the same location as the link source- we want out-of-line links ("link databases");

●

only individual nodes can be linked to- we want links to whole tree fragments;

●

a link always has one source and one destination- we want links with multiple sources and destinations.

●

The XLink pointer model looks like this:

These technologies are not really supported by any browsers today.

XML: XLink, XPointer, and XPath

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Pointing at recipesThe following simple XPath expressions point to parts of the XML recipe document:

//ingrediens[@navn="radiser i små tern"]/@antal

200

//ingrediens[@antal="100" and @enhed="g"]/@navn

flødeost med løg og urterblødt smør i mindre stykkerFeta ost 45+smeltet overtrækschokolade

//titel[text()="Citrontærte"]/following-sibling::ingrediens[@navn="dej"]/tilberedning/text()

Bland mel og sukker i en skål. Skær smørret i mindre stykker ogsmuldr det i melblandingen, til den ligner revet ost. Tilsæt vandog saml hurtigt dejen. Tryk den ud i en smurt springform (ca. 22 cmi diameter). Lad dejen gå halvt op ad formens side. Stil dentildækket i køleskabet i mindst 1 time. Forbag bunden midt i ovneni 12 minutter ved 200 grader.

XPath expressions navigate step by step through the XML tree.

XML: pointing at recipes

http://www.brics.dk/~mis/ITU/XML/xpathrecipe.html [18/09/2000 14:24:39]

XML-QLXML-QL is a query language for XML documents:

XML document can be seen as generalizations of database relations;●

XML-QL is a similar generalization of SQL;●

it can extract data from exisiting XML documents and construct new XML documents.●

Relations are special, restricted cases of XML trees:

XML query languages are not released until 2001.

XML: XML-QL

http://www.brics.dk/~mis/ITU/XML/xmlql.html [18/09/2000 14:24:40]

Querying the recipesThe following XML-QL queries extract information from the XML recipe document:

WHERE <opskriftsamling> <opskrift> <titel>$t</titel> </opskrift> </opskriftsamling>IN "karoline.xml"CONSTRUCT <titel>$t</titel>

<?xml version="1.0"?<<XML> <titel>Filokurve med tigerrejer</titel> <titel>Laksemousse</titel> <titel>Smørrebrød med flødeost og tomat</titel> <titel>Citrontærte</titel> <titel>Hornfisk med radisesalat</titel> <titel>Islagkage med chokolade</titel> <titel>Rabarberdessert med jordbær</titel> <titel>Nougattoppe</titel> <titel>Græsk farsbrød og agurkesalat</titel></XML>

CONSTRUCT <opskriftermedsukker> { WHERE <opskriftsamling> <opskrift> <titel>$t</> <ingrediens*> <ingrediens navn="sukker"/> </> </opskift> </opskriftsamling> IN "karoline.xml" CONSTRUCT <navn>$t</navn>} </opskriftermedsukker>

XML: querying the recipes

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<?xml version="1.0"?><opskriftermedsukker> <navn>Citrontærte</navn> <navn>Islagkage med chokolade</navn> <navn>Rabarberdessert med jordbær</navn></opskriftermedsukker>

WHERE <*><ingrediens navn=$i/></> IN "karoline.xml"CONSTRUCT <ingrediens navn=$i> { WHERE <opskriftsamling> <opskrift> <titel>$t</titel> <*> <ingrediens navn=$i/> </> </opskrift> </opskriftsamling> IN "karoline.xml" CONSTRUCT <ret>$t</ret> } </ingrediens>

<?xml version="1.0"?><XML> <ingrediens navn="æggeblommer"> <ret>Islagkage med chokolade</ret> </ingrediens> <ingrediens navn="friskpresset citronsaft"> <ret>Laksemousse</ret> <ret>Citrontærte</ret> </ingrediens> <ingrediens navn="jordbær i skiver"> <ret>Rabarberdessert med jordbær</ret> </ingrediens> <ingrediens navn="dej"> <ret>Citrontærte</ret> </ingrediens> <ingrediens navn="agurketern"> <ret>Græsk farsbrød og agurkesalat</ret> </ingrediens> <ingrediens navn="hornfisk"> <ret>Hornfisk med radisesalat</ret> </ingrediens> <ingrediens navn="yoghurt"> <ret>Græsk farsbrød og agurkesalat</ret> </ingrediens>

XML: querying the recipes

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<ingrediens navn="kvarkdressing"> <ret>Hornfisk med radisesalat</ret> </ingrediens> <ingrediens navn="sukker"> <ret>Citrontærte</ret> <ret>Rabarberdessert med jordbær</ret> <ret>Islagkage med chokolade</ret> </ingrediens> <ingrediens navn="radisesalat"> <ret>Hornfisk med radisesalat</ret> </ingrediens> <ingrediens navn="mellemstore æg"> <ret>Citrontærte</ret> </ingrediens> <ingrediens navn="rom"> <ret>Islagkage med chokolade</ret> </ingrediens> <ingrediens navn="vand"> <ret>Rabarberdessert med jordbær</ret> <ret>Græsk farsbrød og agurkesalat</ret> <ret>Citrontærte</ret> </ingrediens> <ingrediens navn="koldt smør"> <ret>Citrontærte</ret> </ingrediens> <ingrediens navn="hvedemel"> <ret>Citrontærte</ret> </ingrediens> <ingrediens navn="små papir- eller folieforme"> <ret>Nougattoppe</ret> </ingrediens> <ingrediens navn="fyld"> <ret>Græsk farsbrød og agurkesalat</ret> </ingrediens> <ingrediens navn="fars"> <ret>Græsk farsbrød og agurkesalat</ret> </ingrediens> <ingrediens navn="friskkværnet peber"> <ret>Laksemousse</ret> <ret>Græsk farsbrød og agurkesalat</ret> <ret>Hornfisk med radisesalat</ret> </ingrediens> <ingrediens navn="rabarber"> <ret>Rabarberdessert med jordbær</ret> </ingrediens> <ingrediens navn="agurkesalat"> <ret>Græsk farsbrød og agurkesalat</ret> </ingrediens> <ingrediens navn="bladselleri">

XML: querying the recipes

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<ret>Laksemousse</ret> </ingrediens> <ingrediens navn="knust fed hvidløg"> <ret>Græsk farsbrød og agurkesalat</ret> </ingrediens> <ingrediens navn="piskefløde"> <ret>Nougattoppe</ret> <ret>Islagkage med chokolade</ret> <ret>Laksemousse</ret> </ingrediens> <ingrediens navn="frisk, hakket persille"> <ret>Græsk farsbrød og agurkesalat</ret> </ingrediens> <ingrediens navn="groft salt"> <ret>Laksemousse</ret> <ret>Græsk farsbrød og agurkesalat</ret> <ret>Filokurve med tigerrejer</ret> <ret>Hornfisk med radisesalat</ret> </ingrediens> <ingrediens navn="husblas"> <ret>Laksemousse</ret> </ingrediens> <ingrediens navn="Feta ost 45+"> <ret>Græsk farsbrød og agurkesalat</ret> </ingrediens> <ingrediens navn="frisk, rød chilipeber"> <ret>Filokurve med tigerrejer</ret> </ingrediens> <ingrediens navn="tørret basilikum"> <ret>Smørrebrød med flødeost og tomat</ret> </ingrediens> <ingrediens navn="lille hakket zittauerløg"> <ret>Græsk farsbrød og agurkesalat</ret> </ingrediens> <ingrediens navn="smør"> <ret>Filokurve med tigerrejer</ret> <ret>Græsk farsbrød og agurkesalat</ret> </ingrediens> <ingrediens navn="hakket hvidløgsfed"> <ret>Filokurve med tigerrejer</ret> </ingrediens> <ingrediens navn="creme fraiche"> <ret>Filokurve med tigerrejer</ret> <ret>Laksemousse</ret> </ingrediens> <ingrediens navn="overtræk"> <ret>Islagkage med chokolade</ret> </ingrediens> <ingrediens navn="parfait">

XML: querying the recipes

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<ret>Islagkage med chokolade</ret> </ingrediens> <ingrediens navn="smeltet overtrækschokolade"> <ret>Islagkage med chokolade</ret> </ingrediens> <ingrediens navn="agurk"> <ret>Filokurve med tigerrejer</ret> </ingrediens> <ingrediens navn="udbenet hornfisk"> <ret>Hornfisk med radisesalat</ret> </ingrediens> <ingrediens navn="makronbund"> <ret>Islagkage med chokolade</ret> </ingrediens> <ingrediens navn="olivenolie"> <ret>Filokurve med tigerrejer</ret> </ingrediens> <ingrediens navn="frisk, klippet purløg"> <ret>Hornfisk med radisesalat</ret> </ingrediens> <ingrediens navn="jordbærskiver"> <ret>Rabarberdessert med jordbær</ret> </ingrediens> <ingrediens navn="limefrugt i halve skiver"> <ret>Filokurve med tigerrejer</ret> </ingrediens> <ingrediens navn="creme fraiche 18%"> <ret>Hornfisk med radisesalat</ret> </ingrediens> <ingrediens navn="friske, hakkede citronmelisseblade"> <ret>Filokurve med tigerrejer</ret> </ingrediens> <ingrediens navn="kvark 5+"> <ret>Hornfisk med radisesalat</ret> </ingrediens> <ingrediens navn="frosne, optøede tigerrejer med halevifte"> <ret>Filokurve med tigerrejer</ret> </ingrediens> <ingrediens navn="agurk i små tern"> <ret>Hornfisk med radisesalat</ret> </ingrediens> <ingrediens navn="cherrytomater i skiver"> <ret>Smørrebrød med flødeost og tomat</ret> </ingrediens> <ingrediens navn="magert, hakket svinekød"> <ret>Græsk farsbrød og agurkesalat</ret> </ingrediens> <ingrediens navn="flødeost med løg og urter"> <ret>Smørrebrød med flødeost og tomat</ret>

XML: querying the recipes

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</ingrediens> <ingrediens navn="mælk"> <ret>Græsk farsbrød og agurkesalat</ret> </ingrediens> <ingrediens navn="groft knækbrød"> <ret>Smørrebrød med flødeost og tomat</ret> </ingrediens> <ingrediens navn="hakket lammekød"> <ret>Græsk farsbrød og agurkesalat</ret> </ingrediens> <ingrediens navn="friske citronmelisseblade"> <ret>Citrontærte</ret> </ingrediens> <ingrediens navn="ris"> <ret>Græsk farsbrød og agurkesalat</ret> </ingrediens> <ingrediens navn="frossen, optøet filodej"> <ret>Filokurve med tigerrejer</ret> </ingrediens> <ingrediens navn="citroncreme"> <ret>Citrontærte</ret> </ingrediens> <ingrediens navn="mellemstort æg"> <ret>Græsk farsbrød og agurkesalat</ret> </ingrediens> <ingrediens navn="smeltet smør"> <ret>Filokurve med tigerrejer</ret> </ingrediens> <ingrediens navn="majsstivelse"> <ret>Citrontærte</ret> </ingrediens> <ingrediens navn="parboiled ris"> <ret>Græsk farsbrød og agurkesalat</ret> </ingrediens> <ingrediens navn="blødt smør i mindre stykker"> <ret>Citrontærte</ret> </ingrediens> <ingrediens navn="iskold piskefløde"> <ret>Rabarberdessert med jordbær</ret> </ingrediens> <ingrediens navn="rababerkompot"> <ret>Rabarberdessert med jordbær</ret> </ingrediens> <ingrediens navn="jordbær"> <ret>Rabarberdessert med jordbær</ret> </ingrediens> <ingrediens navn="filokurve"> <ret>Filokurve med tigerrejer</ret> </ingrediens>

XML: querying the recipes

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<ingrediens navn="radiser i små tern"> <ret>Hornfisk med radisesalat</ret> </ingrediens> <ingrediens navn="mørk rom"> <ret>Nougattoppe</ret> </ingrediens> <ingrediens navn="finthakket bladselleri"> <ret>Laksemousse</ret> </ingrediens> <ingrediens navn="overtrækschokolade"> <ret>Islagkage med chokolade</ret> </ingrediens> <ingrediens navn="blød nougat"> <ret>Nougattoppe</ret> </ingrediens> <ingrediens navn="citronbåde"> <ret>Laksemousse</ret> </ingrediens> <ingrediens navn="vanillekorn"> <ret>Islagkage med chokolade</ret> </ingrediens> <ingrediens navn="laks"> <ret>Laksemousse</ret> </ingrediens></XML>

XML: querying the recipes

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XSLTAn XSLT style sheets transforms an XML document into another:

if the target language is XHTML, then this is similar to a CSS style sheet;●

however, often the target language is really another XML language.●

An XSLT style sheet:uses pattern matching and templates to specify the transformation;●

may perform arbitrary computations;●

is vastly more expressive than a CSS style sheet.●

XSLT will be everywhere:browsers will only directly understand the XML language FO (formatting objects);●

HTML will be defined be a canonical XSLT style sheet into FO;●

many applications of XSLT will be involved in rendering a typical document.●

There is little support for XSLT style sheets yet:Netscape 4 does nothing;●

Explorer 5 supports a subset of a deprecated syntax from 1998.●

However, the following service correctly processes an XML document with an associated stylesheet(given a full URL):

XML: XSLT

http://www.brics.dk/~mis/ITU/XML/xslt.html [18/09/2000 14:24:43]

A style sheet for recipesThe following XSLT style sheet illustrates many features (the two namespaces are in different colors):

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0" xmlns="http://www.w3.org/1999/xhtml"> <xsl:template match="opskriftsamling"> <html> <head> <title><xsl:apply-templates select="beskrivelse"/></title> </head> <body> <xsl:apply-templates select="opskrift"/> </body> </html> </xsl:template>

<xsl:template match="beskrivelse"> <xsl:value-of select="text()"/> </xsl:template>

<xsl:template match="opskrift"> <h1> <xsl:value-of select="titel"/><xsl:text> </xsl:text> (<xsl:value-of select="@kvantitet"/>) </h1> <ul> <xsl:apply-templates select="ingrediens"/> <xsl:apply-templates select="tilberedning"/> </ul> <xsl:apply-templates select="garniture"/> <xsl:apply-templates select="servering"/> <xsl:apply-templates select="tips"/> <xsl:apply-templates select="energi"/> <hr/> </xsl:template>

<xsl:template match="ingrediens"> <xsl:choose> <xsl:when test="@antal"> <li> <xsl:if test="@antal!='*'"> <xsl:value-of select="@antal"/> <xsl:text> </xsl:text> <xsl:value-of select="@enhed"/> <xsl:text> </xsl:text> </xsl:if> <xsl:value-of select="@navn"/> </li> </xsl:when>

XML: style sheet for recipes

http://www.brics.dk/~mis/ITU/XML/xsltrecipe.html (1 of 2) [18/09/2000 14:24:44]

<xsl:otherwise> <li><xsl:value-of select="@navn"/></li> <ul> <xsl:apply-templates select="ingrediens"/> <xsl:apply-templates select="tilberedning"/> </ul> </xsl:otherwise> </xsl:choose> </xsl:template>

<xsl:template match="tilberedning"> <xsl:if test="node() or text()"> <li> <i> <xsl:value-of select="text()|node()"/> </i> </li> </xsl:if> </xsl:template>

<xsl:template match="garniture"> <h3>Garniture</h3> <xsl:value-of select="text()|node()"/> </xsl:template>

<xsl:template match="servering"> <h3>Servering</h3> <xsl:value-of select="text()|node()"/> </xsl:template>

<xsl:template match="tips"> <h3>Tips</h3> <xsl:value-of select="text()|node()"/> </xsl:template>

<xsl:template match="energi"> <p/> <table border="2"> <tr> <th>kJoule</th><th>Fedt</th><th>Kulhydrat</th><th>Protein</th> <xsl:if test="@alkohol"> <th>Alkohol</th> </xsl:if> </tr> <tr> <td align="right"><xsl:value-of select="@kjoule"/></td> <td align="right"><xsl:value-of select="@fedt"/>%</td> <td align="right"><xsl:value-of select="@kulhydrat"/>%</td> <td align="right"><xsl:value-of select="@protein"/>%</td> <xsl:if test="@alkohol"> <td align="right"><xsl:value-of select="@alkohol"/>%</td> </xsl:if> </tr> </table> </xsl:template></xsl:stylesheet>

XML: style sheet for recipes

http://www.brics.dk/~mis/ITU/XML/xsltrecipe.html (2 of 2) [18/09/2000 14:24:44]

ExercisesBrowse through the collection of XML applications.1.

Add the recipe for tigerrejer to the XML recipe collection (save as file). Check that the result is well-formed XML.2.

Apply the given style sheet to this extended collection.3.

Add the necessary HTML to the following style sheet:

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0" xmlns="http://www.w3.org/1999/xhtml">

<xsl:template match="opskriftsamling"> <html> <xsl:apply-templates select="opskrift"/> </html> </xsl:template>

<xsl:template match="opskrift"> <xsl:value-of select="titel"/> <xsl:value-of select="energi/@kjoule"/> <xsl:value-of select="energi/@fedt"/> <xsl:value-of select="energi/@kulhydrat"/> <xsl:value-of select="energi/@protein"/> <xsl:if test="energi/@alkohol"> <xsl:value-of select="energi/@alkohol"/> </xsl:if> </xsl:template>

</xsl:stylesheet>

which extracts nutrition tables from recipe collections. Try it out. As it stands, the output looks like:

<?xml version="1.0" encoding="ISO-8859-1"?><html xmlns="http://www.w3.org/1999/xhtml">Smørrebrød med flødeost og tomat2616553411Citrontærte1510065314Græsk farsbrød ogagurkesalat13920463519Islagkage medchokolade21655672742Laksemousse5838611722Nougattoppe8616692542Rabarberdessert medjordbær852044542Hornfisk med radisesalat9140283834</html>

4.

XML: exercises

http://www.brics.dk/~mis/ITU/XML/exercises.html [18/09/2000 14:24:45]