Editing Meta Content Framework

'''Meta Content Framework''' ('''MCF''') is a specification of a [[content format]] for structuring [[metadata]] about [[web site]]s and other [[data]].

==History==
MCF was developed by [[Ramanathan V. Guha]] at [[Apple Advanced Technology Group|Apple Computer's Advanced Technology Group]] between 1995 and 1997. Rooted in [[Knowledge representation and reasoning | knowledge-representation]] systems such as [[CycL]], [[KRL (programming language)| KRL]], and [[Knowledge Interchange Format|KIF]], it sought to describe objects, their attributes, and the relationships between them.<ref name=hammersley>{{Cite book| publisher = O'Reilly| isbn = 978-0-596-00383-8| last = Hammersley| first = Ben| title = Content Syndication with RSS| location = Sebastopol| date = 2003| page = [https://archive.org/details/contentsyndicati00hamm/page/2 2]| url-access = registration| url = https://archive.org/details/contentsyndicati00hamm/page/2}}</ref>

One application of MCF was [[HotSauce]], also developed by Guha while at Apple. It generated a [[3D computer graphics|3D]] [[visualization (graphic)|visualization]] of a web site's table of contents, based on MCF descriptions. By late 1996, a few hundred sites were creating MCF files and Apple HotSauce allowed users to browse these MCF representations in 3D.<ref name=hammersley />

When the research project was discontinued, Guha left Apple for [[Netscape Communications Corporation|Netscape]], where, in collaboration with [[Tim Bray]], he adapted MCF to use [[XML]]<ref>{{Cite conference
| publisher = W3C
| last = Guha
| first = R V
|author2=Tim Bray
 | title = Meta Content Framework Using XML
| accessdate = 2014-09-14
| date = 1997-06-06
| url = http://www.w3.org/TR/NOTE-MCF-XML/
}}</ref><ref>{{Cite web|last1=Guha |first1=R.V. |last2=Bray |first2=Tim |title=Meta Content Framework Using XML |work=Netscape |accessdate=2015-12-12 |date=1997-06-13 |url=http://developer.netscape.com/mcf.html |url-status=dead |archiveurl=https://web.archive.org/web/19970615144715/http://developer.netscape.com/mcf.html |archivedate=June 15, 1997 }}</ref> and created the first version of the [[Resource Description Framework]] (RDF).<ref>{{Cite web|last=Andreessen |first=Marc |title=Innovators of the Net: R.V. Guha and RDF |work=Netscape |accessdate=2014-09-14 |date=1999-01-08 |url=http://wp.netscape.com/columns/techvision/innovators_rg.html |url-status=dead |archiveurl=https://web.archive.org/web/20080205163659/http://wp.netscape.com/columns/techvision/innovators_rg.html |archivedate=February 5, 2008 }}</ref>

== MCF format ==
An MCF file consists of one or more blocks, each corresponding to an entity. A block looks like this:<syntaxhighlight lang="text" line="1">
Node: <identifier>
<property>: <value>, <value>
</syntaxhighlight>The identifier is a unique identifier for that entity (more on the scope of the identifier below) and is used to refer to that entity. The following lines each specify a property and one or more values, separated by commas. Each value can be a reference to another entity (via its identifier), a string (enclosed by double quotes) or a number. For example:<syntaxhighlight lang="text" line="1">
Node: Test1
typeOf: TestNode
child: Test2, Test3
name: "I am a test node"
itemCode: 42

Node: Test2
typeOf: TestNode
sibling: Test3
name: "I am another test node in a test world"

Node: Test3
typeOf: TestNode
sibling: Test2
name: "Just another test node in a test world"
</syntaxhighlight>NOTE: 

* The identifier must not include a comma (<code>,</code>) and must not be enclosed within double quotes.
* A common parsing failure is due to odd number of unescaped double quotes in text. For instance, <code>"foo bar" baz"</code> needs to be <code>"foo bar\" baz"</code>.
* Commas within double quotes are not considered as value separators.
* Every entity has at least one property: <code>typeOf</code>.

==References==
{{reflist}}

==External links==
*[http://www.textuality.com/mcf/MCF-tutorial.html MCF Tutorial] (using XML syntax)
*[https://web.archive.org/web/20110609105849/http://www.guha.com/mcf/ Guha MCF site]
*[http://downlode.org/Etext/MCF/towards_a_theory_of_metacontent.html The metacontent concept]

[[Category:Knowledge representation]]
[[Category:Apple Inc. software]]

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