=?UTF-8?Q?Re=3A_=5Bxml=2Ddev=5D_The_semantics_of_an_XML_document_is

On Sat, 8 Jan 2022 at 13:28, Roger L Costello <costello@mitre.org> wrote:

Hi David,

That's a very strange interpretation of "semantics"

My interpretation of “semantics” is consistent (I think) with how mathematicians define the semantics of an expression. For example, I believe that a mathematician would say the semantics of this expression:

1 + 1

is: 2

In other words, the semantics of the expression is determined by the actions taken on the expression.

Compare that with what I said:

The semantics of an XML document is determined by the actions taken on the XML document.

I think that I am being consistent with mathematicians. Do you agree?

no, the semantics of the expression is "addition" but the input to the addition operator there are "two integers 1 and 1" and it is that that corresponds to the xml document which was the input to your two different operations. The pair of integers (1,1) has the same meaning (semantics) whether you apply addition and get 2 or apply subtraction and get 0. There are other interpretations (1,1) that aren't a pair of integers (eg a cartesian coordinate of a point in a plane) so the semantics of the syntax (1,1) just like the semantics of your xml, needs to be stated elsewhere but is independent of any operation you may or may not do on the data,

David

/Roger

From: David Carlisle <d.p.carlisle@gmail.com>
Sent: Saturday, January 8, 2022 8:14 AM
To: Roger L Costello <costello@mitre.org>
Cc: xml-dev@lists.xml.org
Subject: [EXT] Re: [xml-dev] The semantics of an XML document is …

On Sat, 8 Jan 2022 at 13:04, Roger L Costello <costello@mitre.org> wrote:

Hi Folks,

The semantics of an XML document is determined by the actions taken on the XML document.

Consider this XML document:

<airplane-flight>
<duration units="hours">1</duration>
<speed units="kilometers-per-hour">500</speed>
</airplane-flight>

What is its semantics?

Answer: it has no semantics because it has no actions.

Pair up the XML document with actions that compute duration * speed (i.e., distance traveled by the airplane flight):

The semantics of the XML document is: 500

Pair up the XML document with different actions and it has different semantics:

Now the semantics of the XML document is: 310.686

----------------------------------------------

Wicked cool!

Comments?

/Roger

That's a very strange interpretation of "semantics" you have two calculations both with the same data so the semantics (meaning) of the document is the same in both cases and is the interpretation of the elements. For example the interpretation of <duration units="hours">1</duration> as meaning 1 hour, that interpretation (which is external to the document) is the same in both cases. and (probably) the same if you just store the xml and never do any calculation at all.

David