-
Notifications
You must be signed in to change notification settings - Fork 0
Exploring_XML
XML = Extensible Markup Language
The main purpose of XML is serialization, i.e. storing, transmitting, and reconstructing arbitrary data.
Gathering of existing material ...
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. 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
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.
Feature require: 'YAXO'
example
XMLDOMParser addressBookXMLWithDTD
XMLDOMParser parseDocumentFrom: XMLTokenizer addressBookXMLWithDTD readStream
https://wiki.squeak.org/squeak/6338
https://wiki.squeak.org/squeak/6342
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; probably not much.
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
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.
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
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
Tune: Mary had a little lamb
MusicXML notation
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
Download current DrGeo Desktop menu -> Tools -> SystemBrowser
Creation of an XMLElement (taken from class side)
XMLNodeWithElements subclass: #XMLElement
instanceVariableNames: 'name contents attributes'
classVariableNames: ''
poolDictionaries: ''
category: 'YAXO'
Go to XMLElement in the class Browser, class side
Click on method named: aString attributes: attributeList Go for senders of it.
You will find for example how an XMLElement is constructed to write out a rectangle as SVG
DrGSvgCanvas
rectangle: rect
| rectNode |
rectNode := XMLElement
named: #rect
attributes: {
#x -> rect topLeft x asString . #y -> rect topLeft y asString .
#width -> rect width asString . #height -> rect height asString } asDictionary.
^ rectNode
And then this #rectangle: method is called by DrGSvgCanvas #fillRectangle:color:
fillRectangle: rect color: fillColor
| rectNode |
rectNode := self rectangle: rect.
self styleOf: rectNode StrokeWidth: nil color: nil fillColor: fillColor.
svgTree addElement: rectNode
More attributes are filled in for example
DrSvgCanvas
styleOf: element StrokeWidth: strokeWidth color: strokeColor strokeDashArray: sda strokeDashArrayOffset: sdao fillColor: fillColor
"
Apply style to a given element (node)
"
strokeWidth ifNotNil: [element attributeAt: #'stroke-width' put: strokeWidth asString].
strokeColor ifNotNil: [ element attributeAt: #stroke put:
(strokeColor isTransparent ifTrue: ['transparent'] ifFalse: strokeColor hexHtml)].
sda ifNotNil: [
element
attributeAt: #'stroke-dasharray'
put: (String streamContents: [:s | sda do: [:e | s store: e] separatedBy: [ s space]])].
sdao ifNotNil: [element attributeAt: #'stroke-dashoffset' put: sdao asString].
fillColor
ifNotNil: [
element attributeAt: #fill put: fillColor hexHtml.
fillColor isOpaque ifFalse: [element attributeAt: #'fill-opacity' put: fillColor alpha asString] ]
ifNil: [element attributeAt: #fill put: 'none']
pathNode := XMLElement named: #path.
Explore classes:
DrGeoXML DrGSvgCanvas
Next thing to do: Read the MusicXML file, access the tune and play it.