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Exploring_XML

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hhzl edited this page May 19, 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

YAXO was first introduced in Squeak 3.3.

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. 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/6342

Accessing the topElement element

Cuis has xmlDocument topElement while Squeak has #root. But that refers just to #topElement https://wiki.squeak.org/squeak/6439

Squeak tutorial

Squeak has an XML tutorial which explains how to access information in a rss page.

doc := HTTPClient httpGetDocument: 'http://source.squeak.org/trunk/feed.rss'.
	XMLDOMParser parseDocumentFrom: (ReadStream on: (doc content)).

for more see Squeak 6.0. adapt it for Cuis; seems not to work; check again.

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

From Pharo examples 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>'.

"adapted 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

xmlString := 
'<?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>'.

XMLDOMParser  parseDocumentFrom: xmlString readStream

Exploring MusicXML

Tune: Mary had a little lamb

ABC notation https://abcnotation.com/tunePage?a=trillian.mit.edu/~jc/music/abc/mirror/musicaviva.com/england/mary-had-a-little-lamb-f/0000

MusicXML notation

https://abcnotation.com/getResource/downloads/code_/mary-had-a-little-lamb.xml?a=trillian.mit.edu/~jc/music/abc/mirror/musicaviva.com/england/mary-had-a-little-lamb-f/0000

https://musescore.com/user/34504790/scores/6127202 Clicking the download button offers to download it in MusicXML.

https://abcnotation.com/tunePage?a=trillian.mit.edu/~jc/music/abc/mirror/back.numachi.com/Frere_Jacques/0000 MusicXML https://abcnotation.com/getResource/downloads/code_/frere-jacques.xml?a=back.numachi.com:8000/dtrad/abc_dtrad.tar.gz/abc_dtrad/FRERJACQ/0000

Next

Next thing to do: Read the MusicXML file, access the tune and play it.

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