© Disruptive Innovations 2006 Etna a wysiwyg XML RELAXNG- and Gecko-based editor

© Disruptive Innovations 2006

http://disruptive-innovations.com

Etna

a wysiwyg XML RELAXNG- and Gecko-based editor



What is Etna?

• Editing Tool for Networked Authors• an XML editor• sponsored by the Connexions Project• Open-Source MPL/GPL/LGPL• cross-platform• based on Gecko

http://cnx.org



Genesis

• Connexions needed a standalone editor– simple to use for people w/o xml knowledge– for the academic world– localizable, internationalizable– power without complexity– markup quality– independent



Requirements

• Wysiwyg

• Open-source, MPL-style preferred

• RELAX NG

• validating editor

• independence



Choices

• Gecko– cross-platform– MPL/GPL/LGPL– great I18n/l10n– great extensibility

• our own RELAX NG implementation



Constraints 1: simplicity

– don’t show the markup!– don’t require XML knowledge at all– don’t show technical details but human friendly

texts– the schema’s author should be able to specify

default behaviours instead of forcing the user to make choices

– the rendering in the editor should be the one a modern browser like Firefox will show/print



Constraints 2 : clean

– Impossible to create or save invalid markup– RELAX NG validator queried by the UI layer– Impossible to load invalid markup



First (bad) idea

– Reuse Nvu, and do some magic to show and manipulate HTML while we internally edit XML

• Was probably our stupidest idea ever

• So we decided to implement a new XML editor in Gecko



libeditor/xml

– XML editor– RELAX NG parser

• Generates a graph from a domdocument holding a relax ng schema

– RELAX NG validator• Validates a domdocument against a relax ng graph

– RELAX NG queries and actions API• Allows to query the graph of a relax ng schema



parser: our extensions 1

– our own namespace• http://disruptive-innovations.com/ns/editor-rng-

extensions/1.0

– <di:blank>• defines a « blank » instance for a given rng pattern;

multiple blanks are allowed

– <di:defaultValue>• default value for attribute patterns




– <di:externalDoctype>• doctype to be added to document instances based on

the schema

– <di:processingInstruction>• creates a PI in the pattern

– <di:label>, <di:description>• human-readable info for a pattern (Cf. Grif 1989 !!!)

– <di:localizationProperties>• more specifically to extend Etna




– <di:editorStylesheets>• to specify stylesheets only using when editing a

document based on the current schema

– <di:collapsedSelection>, <di:startSelection>, <di:endSelection>

• to specify what should be the selection or the caret’s position inside a new « blank » pattern




– <di:semantics>• work in progress…

• we need a way to specify an element « is » a list item, a table cell, …

• we’re not sure yet it should be in the schema

• but we don’t want yet another parser, selectors mechanism and path




– <di:behaviours>• listen before screaming :-)

• we claim it should be the RNG author’s responsability to specify two CRs at the end of a list item end the list and create a paragraph

• so we need a solution describing behaviours and attaching them to pattens




– we are open to dicussion– we are open to (deep) changes– we are open to standardization– we just want a viable, reliable, simple solution

for problems all SGML/XML folks have been fighting with for TWENTY YEARS.



validator

– validates a domdocument against a RNG schema loaded by our schema manager

– hidden by the XML editor and the nsEditingSession

– from an implementor’s perspective, just like nsPlaintextEditor or nsHTMLEditor…



queries: examples

– query the rng schema to know if the result of a given action is valid

– canDeleteNode(in DOMNode node)

– canSetAttribute(in DOMElement elt, in string name, in URI namespaceUri, in string value)

– canDeleteSelection()

– have access to label, description, … for a given node

– get the list of possible « blanks »



actions: examples

– allow to perform actions on the document, in full conformance with the schema

• create « blanks », triggering UI prompts when needed

– doDeleteNode(in DOMNode node)

– doSetAttribute(in DOMElement elt, in string name, in URI namespaceUri, in string value)

– doDeleteSelection()



Etna: what else ?

– extensible set of datatypes: RNG datatypes and a lot of XML Schema datatypes by default

– in theory, the validator is not RNG-specific and can be adapted to other schema languages



The future of Etna

– help schema authors build UI extensions specific to their schemas

– MathML– tabeditor…– xulrunner– world domination



Conclusion

– Etna is not only an XML editor• it’s also the proof a major project like a wysiwyg

XML editor based on Gecko is possible, feasible ; that’s a superb indicator of maturity for Mozilla

• it’s also the live proof that it’s possible to solve VERY OLD issues with markup-based authoring

• in the long run, we hope to provide schema authors and the masses with a tool completely hiding the complexity of markup languages



Links

• http://cnx.org

• http://rhaptos.org/downloads/editing/etna/

Documents

© Disruptive Innovations 2006 Etna a wysiwyg XML RELAXNG- and Gecko-based editor