Re: [xml-dev] RE: The semantics of an XML document is …
Eighteen years ago, I wrote “On Semantics and Markup”: https://www.tbray.org/ongoing/When/200x/2003/04/09/SemanticMarkupI think I still mostly believe everything in that essay. It addresses three questions:
- When is markup semantic?
- Is semantic-ness a binary condition?
- Where do semantics come from?
and ends with this summary:
- Descriptive markup is better than the alternatives.
Descriptive markup is not necessarily semantic.
The phrase “semantic markup” constitutes a claim that needs to be demonstrated before being accepted.
Semantics don't come from schemas.
On Sat, Jan 8, 2022 at 9:03 AM Jean Kaplansky <[email protected]> wrote:No. I don’t agree.Behavior is not part of the dictionary definition of semantics:(OED is behind a paywall)--On Sat, Jan 8, 2022 at 8:18 AM Roger L Costello <[email protected]> wrote:Hi Folks,
In my previous post I wrote this: When there are no actions associated with the XML document:
- What is its semantics?
- Answer: it has no semantics because it has no actions.
It just occurred to me that it might be more correct to say that its semantics is “undefined.”
Do you agree?
If you agree, then is the “undefined semantics” concept analogous to the “undefined behavior” one reads about in programming language specifications?
/Roger
From: Roger L Costello <[email protected]>
Sent: Saturday, January 8, 2022 8:04 AM
To: [email protected]
Subject: The semantics of an XML document is …
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
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Wicked cool!
Comments?
/Roger