Skip to content

Exploring_XML

Jump to bottom
hhzl edited this page May 17, 2025 · 34 revisions

XML = Extensible Markup Language

The main purpose of XML is serialization, i.e. storing, transmitting, and reconstructing arbitrary data.

Gathering of existing material ...

Origin of the YAXO parser used in Cuis

https://wiki.squeak.org/squeak/2256 4744YAXO – Duane Maxwell, Andres Valloud, Michael Rueger – 25 January 2002 YAX is yet another XML parser. This version is an effort to further integrate the original yax version with the Exobox implementation. The original yax version already was based on some ideas in the Comanche tokenizer and the Exobox parser. The YAX homepage is at http://www.squeaklet.com/Yax/index.html. This change set includes a XMLParser with SAX and DOM support and a XMLWriter.

Introduction https://wiki.squeak.org/squeak/1407

What is XML?

https://www.w3schools.com/xml/xml_whatis.asp

<note>
  <to>Tove</to>
  <from>Jani</from>
  <heading>Reminder</heading>
  <body>Don't forget me this weekend!</body>
</note>

The XML above is quite self-descriptive:

  • It has sender information
  • It has receiver information
  • It has a heading
  • It has a message body

But still, the XML above does not DO anything. XML is just information wrapped in tags.

Installation

Feature require: 'YAXO'

example

XMLDOMParser addressBookXMLWithDTD

XMLDOMParser  parseDocumentFrom: XMLTokenizer addressBookXMLWithDTD readStream

Writing a XML file

https://wiki.squeak.org/squeak/6338

Reading a XML file

https://wiki.squeak.org/squeak/6433

Erudite

Lift out examples from Erudite https://github.com/Cuis-Smalltalk/Erudite

https://raw.githubusercontent.com/Cuis-Smalltalk/Erudite/refs/heads/master/Examples/xmlbook3.xml Add the statement which reads this here

FAO country names example

https://wiki.squeak.org/squeak/6342

(XMLDOMParser parseFileNamed: 'fao_country_names.xml')
  firstNode
  allElementsSelect: [ : each |
    each localName = 'geographical_region' ].

The file fao_country_names.xml seems to be no longer available in XML, see https://data.apps.fao.org/catalog/dataset/country-names

Find another candidate.

Pharo

https://github.com/pharo-contributions/XML-XMLParser

|xmlString|
xmlString := '<?xml version="1.0" encoding="UTF-8"?>
<countries>
  <country code="af" handle="afghanistan" continent="asia" iso="4">Afghanistan</country>
  <country code="al" handle="albania" continent="europe" iso="8">Albania</country>
  <country code="dz" handle="algeria" continent="africa" iso="12">Algeria</country>
</countries>'.

"(XMLDOMParser parse: xmlString) document root nodes inspect Does not work, needs to be adapted.

"correct for Cuis"

XMLDOMParser  parseDocumentFrom: xmlString readStream

13 year old Pharo video https://www.youtube.com/watch?v=6q78hzawfGU

An example of a XML file standard: MusicXML

https://www.w3.org/2021/06/musicxml40/tutorial/hello-world/

"Hello World" program in MusicXML

XMLDOMParser  parseDocumentFrom: 
'<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE score-partwise PUBLIC
    "-//Recordare//DTD MusicXML 4.0 Partwise//EN"
    "http://www.musicxml.org/dtds/partwise.dtd">
<score-partwise version="4.0">
  <part-list>
    <score-part id="P1">
      <part-name>Music</part-name>
    </score-part>
  </part-list>
  <part id="P1">
    <measure number="1">
      <attributes>
        <divisions>1</divisions>
        <key>
          <fifths>0</fifths>
        </key>
        <time>
          <beats>4</beats>
          <beat-type>4</beat-type>
        </time>
        <clef>
          <sign>G</sign>
          <line>2</line>
        </clef>
      </attributes>
      <note>
        <pitch>
          <step>C</step>
          <octave>4</octave>
        </pitch>
        <duration>4</duration>
        <type>whole</type>
      </note>
    </measure>
  </part>
</score-partwise>'

Clone this wiki locally