XML and Lexical Resources. Shakil Nasir

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1 XML and Lexical Resources Shakil Nasir

2 Content Introduction to XML XML Basics Validation of XML Documents DTD Basics Lexical Resources Repository of Online Urdu Dictionary

3 Introduction to XML XML (Extensible Markup Language) defines structure and content of different types of electronic documents History 1986: Standard Generalized Markup Language (SGML) developed as standard 1997: HTML 4.0 and XML 1.0 Recommendations proposed 1999: XHTML Standard developed

4 XML Repository: Benefits Simple Open W3C standard Platform Independent Separate Data from Presentation Strict Validation Easy Parsing Multi-lingual Support (Unicode) Self-Descriptive Exchange of Information

5 XML: Building Blocks Element Simple (Contains content (simple text); does not contain any nested element) Complex (Contains one or more nested element; does not contain content) Mixed (Contains both content and nest elements) Tag Start and End tags tells about start and end of an element Attribute Additional features of an element Content

6 Example < date= 20/2/05 > <to>william</to> <from>martin</from> <subject>important</subject> <body>some message</body> </ >

7 XML Attributes vs. child XML Elements < date="12/11/2002" > <to>william</to> <from>martin</from> <subject>important</subject> <body>some Message</body> </ > < > <date>12/11/2002</date> <to>william</to> <from>martin</from> <subject>important</subject> <body>some message</body> </ >

8 XML Document XML Document Parts XML declaration Root Element Example: XML Document <?xml version="1.0" encoding= utf-8"?> < > <to>william</to> <from>martin</from> <subject>important</subject> <body>some message</body> </ > Comments

9 XML Document (Contd.) XML is simple but strict An XML document must have single Root element XML tags are case sensitive Example: <Note> is different from <note> All XML elements must be properly nested All XML elements must have ending tag Attribute values must always be quoted

10 XML Namespace Name conflicts Solution: Use prefix <h:table> <h:tr> <h:td>apples</h:td> <h:td>bananas</h:td> </h:tr> </h:table> <f:table> <f:name>african Coffee Table</f:name> <f:width>80</f:width> <f:length>120</f:length> </f:table>

11 XML Namespaces (Contd.) Solution: Using Namespace <h:table xmlns:h=" <h:tr> <h:td>apples</h:td> <h:td>bananas</h:td> </h:tr> </h:table> XML Namespace (xmlns) Attribute

12 XML-Related Technologies XSL (Extensible Style Sheet Language) Consists of 3 components: XSLT, XPath and XSL-FO XSLT (XSL Transformations) Transforms XML documents into other XML formats, like XHTML XSL-FO (Extensible Style Sheet Language Formatting Objects) Applies formatting to XML data to output to screen, paper or other media.

13 XML-Related Technologies (Contd.) DTD (Document Type Definition) Defines the legal elements in an XML document. XML Schema Alternative to DTDs. XQuery (XML Query Language) Allows to query in XML data. SOAP (Simple Object Access Protocol) An XML-based protocol to let applications exchange information over HTTP.

14 Validation of XML Documents Well-Formed XML documents XML documents contain text and XML tags which conform to the XML syntax Valid XML documents XML documents must be well formed and are additionally error checked against an XML grammar (DTD or schema) XML Grammar Definition Defines the legal elements and structure of an XML document Two alternatives XML DTD XML Schema

15 XML and DTD Defines the legal building blocks and structure of an XML document Inline declared vs. reference to an external DTD Building Blocks Elements Attributes PCDATA vs. CDATA

16 XML and DTD: Example (Inline) <?xml version="1.0"?> <!DOCTYPE [ <!ELEMENT note (to,from,subject,(message body))> <!ELEMENT to (#PCDATA)> <!ELEMENT from (#PCDATA)> <!ELEMENT subject (#PCDATA)> <!ELEMENT body (#PCDATA)> <!ATTLIST note date CDATA #REQUIRED> ]> < date= 12/2/05 > <to>william</to> <from>martin</from> <subject>reminder</subject> <body>some message</body> </ >

17 XML and DTD: Example (Extrenal) DTD File <!ELEMENT note (to,from,subject,(message body))> <!ELEMENT to (#PCDATA)> <!ELEMENT from (#PCDATA)> <!ELEMENT subject (#PCDATA)> <!ELEMENT body (#PCDATA)> <!ATTLIST note date CDATA #REQUIRED> XML Document <?xml version="1.0"?> <!DOCTYPE SYSTEM .dtd > < date= 12/2/05 > <to>william</to> <from>martin</from> <subject>reminder</subject> <body>some message</body> </ >

18 Manipulating XML Documents XML Parser / Processors MSXML 4.0, Xerces C++, Xerces for Java etc. Example [Javascript]: Loading XML document in Parser <script type="text/javascript"> var xmldoc = new ActiveXObject("Microsoft.XMLDOM")xmlDoc.async="false xmldoc.load("note.xml") //... </script>

19 Validation with XML parser var xmldoc=new ActiveXObject("Microsoft.XMLDOM") xmldoc.async="false xmldoc.validateonparse="true xmldoc.load("note_dtd_error.xml )

20 Lexical Resources A database collection consisting of entries; each of which entry documents a lexeme, and provides one or more senses (concepts) and other linguistic info. associated with that word. Examples: Online dictionaries, Machinetranslation lexicons XML files can used as a repository for a lexical resource

21 Lexicon Repository Lexicon Engine consists of two repositories of lexicon data XML data repository Index data repository XML data repository contains all available information of words in the form of XML tags XML file for each word Indexes are stored on disk in binary format (Hashtables, Btrees etc.)

22 XML Repository in Online Urdu Dictionary (OUD)

23 Compact Model of OUD Lexical Resource

24 Sample Linguistic Dimensions and their XML Tags Linguistic Dimensions Example Headword Lexical Entry Meaning Number Plural POS Pronunciation Root-language Sense Singular Sub-sense Tag Names eg headword word mean num pl pos pron root-lang sense sing sub-sense

25 Sample XML Word Entry <?xml version="1.0" encoding="utf-16"?> <!DOCTYPE SYSTEM urdu_dictionary.dtd > <word> < headword />باد شاہ< headword > + شاہ< pron > < pron />باد < root-lang />فارسی< root-lang > <pos type="noun"> < num />واحد< num > < pl />باد شاہان< pl > <sense><sub-sense> صاحب تخت و تاج خود مختار حکمران جو کسی کے سامنے جواب دہ نہ <mean> < mean />ہو بہادر شاہ کو انگریز پکڑ کر کالے پانی لے گے تو انگریز بادشاہ ہوۓ یا نہ ہوۓ <eg> </eg> </sub-sense></sense> <sense><sub-sense> <mean> خداوند حاکم < mean />مالک </sub-sense></sense> </pos> </word>

26 Sample DTD <!ELEMENT word (headword,pron,root-lang?,pos+)> <!ELEMENT headword (#PCDATA)> <!ELEMENT pron (#PCDATA)> <!ELEMENT root-lang (#PCDATA)> <!ELEMENT pos (num?,sing?,pl?,sense+)> <!ELEMENT sense (sub-sense)+> <!ELEMENT sub-sense (mean,eg?)+> <!ATTLIST pos type (noun adjective adverb verb pronoun other) #REQUIRED>

XML: extensible Markup Language. Anabel Fraga

XML: extensible Markup Language Anabel Fraga Table of Contents Historic Introduction XML vs. HTML XML Characteristics HTML Document XML Document XML General Rules Well Formed and Valid Documents Elements