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Re: Philosophy of XML datatypes (was: What is an integer?(was:

• From: "Ghislain Fourny" <gfourny@inf.ethz.ch>
• To: Peter Flynn <peter@silmaril.ie>
• Date: Wed, 29 Mar 2023 14:43:54 +0000

> On 26/03/2023 20:28, Roger L Costello wrote:
>> <num>44</num>
>> The value of the <num> element -- 44 -- represents an integer.
> 
> No, the *value* of the <num> element *is* an integer. It's the '44' that *represents* an integer.

Formally, in XML Schema, this is captured by types having a value space and a lexical space.

The value space of xs:integer is the set of the actual mathematical integers, so Z.

The lexical space of xs:integer is the set of strings corresponding to the decimal representation of an integer.

The lexical mapping of xs:integer maps each string representation (also called a literal, this is what appears in XML as text) to an integer value in the value space.

That way, when working with XPath or XQuery or XSLT, actual integers are manipulated.

The canonical mapping maps in the other direction from an integer to its “most natural” literal, but does so by prescription so because this is a convention.

This allows serializing query results back to XML.

Kind regards,
Ghislain

• References:
  • XML Quiz
    • From: Roger L Costello <costello@mitre.org>
  • What is an integer? (was: Re: XML Quiz)
    • From: Roger L Costello <costello@mitre.org>
  • Philosophy of XML datatypes (was: What is an integer? (was: Re: XML Quiz))
    • From: Roger L Costello <costello@mitre.org>
  • Re: Philosophy of XML datatypes (was: What is an integer?(was: Re: XML Quiz))
    • From: Peter Flynn <peter@silmaril.ie>