Re: [xml-dev] RE: When you create a markup language, what do yourparent

[cbullard@hiwaay.net]

HAS-A

len


Quoting "Cox, Bruce" <Bruce.Cox@USPTO.GOV>:

> Seems to me, they mean whatever the business they model needs them  
> to mean.  The terms "parent" and "child" are a convenient metaphor  
> describing an abstraction that can model many different  
> relationships, including (literally) parent-child, object-property,  
> organism-organ, machine-component, heading-subheading,  
> continent-subcontinent, molecule-atom, antecedent-consequent,  
> husband-wife, genus-species, list-list item, state-county,  
> congress-congress one, employer-employee, boss-subordinate,  
> teacher-student, class-roster, set-members, galaxy-solar system,  
> solar system-planets, planet-satellites, creator-creation,  
> premises-conclusion, inventor-invention, and many other relationships.
>
> I could be wrong, Roger, but it seems to me that the XSLT fragment  
> specifies an operation, which when executed, defines a set by  
> selecting its members.  Saying that it "defines a truth" seems a bit  
> of a stretch, in the sense that the membership of the set will vary  
> with the instances to which the fragment is applied.  The set could  
> end up empty, in which case the statement "For each cost element, c,  
> c is greater than 0" would not be true.  For XSLT, I'd say the  
> parent-child terms are operation-output, which is always true since  
> it includes the case where the output is null.
>
> Bruce B Cox
> Director, Usability and Design Division, OCIO, USPTO
>
> -----Original Message-----
> From: Costello, Roger L. [mailto:costello@mitre.org]
> Sent: 2011 September 26, Monday 08:54
> To: xml-dev@lists.xml.org
> Subject: When you create a markup language, what do your parent  
> elements mean? What do your children elements mean?
>
> Hi Folks,
>
> How do you define a parent element and its children?
>
> The Geography Markup Language (GML) defines a parent element as  
> corresponding to a real-world object and its children as properties  
> of the real-world object. Thus, parent-child means object-property.  
> For example, a Bridge is a real-world object and thus is the name of  
> the parent element. Total-length, width, and crosses are properties  
> of Bridge and thus are the names of its children:
>
> <?xml version="1.0" encoding="UTF-8"?>
> <Bridge>
>     <total-length>_____</total-length>
>     <width>_____</width>
>     <crosses>_____</crosses>
> </Bridge>
>
> All GML applications treat a parent element as an object and its  
> children as properties of the object.
>
> GML takes an Object-Oriented perspective on the meaning of markup.
>
> (The following discussion on XSLT may be stated better and/or more  
> accurately; I invite your revision)
>
> XSLT takes a different perspective. XSLT takes the perspective that  
> markup is a definition. For example, the following XSLT makes this  
> definition: "For each cost element, c, c is greater than 0":
>
> <xsl:for-each select="//cost">
>     <xsl:variable name="c" select="xs:integer(.)" />
>     <xsl:value-of select="c &gt; 0" />
> </xsl:for-each>
>
> Each XSLT processor treats the for-each parent element as an  
> expression of a truth (specified by its children) over the range of  
> values indicated in the select attribute.
>
> XSLT takes a Functional perspective on the meaning of markup.
>
> Recap: here are two ways of defining the meaning of markup:
>
> 1. Object-property
> 2. Functional definition
>
> What other ways are there?
>
> When you create a markup language, what do your parent elements  
> mean? What do your children elements mean?
>
> /Roger
>
>