[whatwg] [html5] tags, elements and generated DOM

Lachlan Hunt lachlan.hunt at lachy.id.au
Wed Apr 6 06:32:47 PDT 2005

Anne van Kesteren wrote:
> Lachlan Hunt wrote:
>> | Conformance checkers that only perform validation are non-conformant,
> So? That doesn't make it a validator.

What is a validator, if it is not a form of "conformance checker that 
only peforms validation" then?  Or, the other way around, what is a 
"conformance checker that only performs validation" if it is not a 

> A conformance checker might do things validators do too, but that
> doesn't make it one.

I belive such conformance checkers are often called lints and they are 
usually not true validators, despite what many claim, so you are correct 
in that a conformance checker may not be a validator.  But, from what I 
understand of the wording in the spec, a validator is a form of 
conformance checker.  Basically, metaphorically speaking, it's like a 
square is a rectangle, but a rectangle is not always a square.

>> In fact, now that I've read it again, it seems rather contradictory.
> How?

Did I not explain it well enough before?  See below.

>> I would argue that conformance requirements that cannot be expressed 
>> by a DTD *are* constraints that require interpretation by the author.
> Not really.

Yes, really.

>  Think about:
>  <http://annevankesteren.nl/archives/2003/09/invalid-after-validated>

Exactly, the conformance constraints violated in those examples cannot 
be expressed in an XML DTD (some can, and are, by the HTML4 DTD though), 
and require interpretation by the author.  This merely illustrates the 
difference between "valid" and "conformant".

>> Therefore, that section seems to be saying that validators are exempt
>> from checking some things, but are non-conformant for not checking 
>> them anyway.

That is how the spec is contradictory, except s/validators/conformance 
checkers/ and with "some things" meaning "errors that require 
interpretation of the author's intent"

Because, if I am understanding correctly and a validator is a form of 
conformance checker, a validator cannot check constraints that are not 
expressed in the DTD and require them to be interpreted by the author. 
Therefore, validators are exempt from checking such constraints, but are 
non-conformant for not checking them anyway, as stated in the note. 
(well done if you are not totally confused by that, I tried to make it 
as clear as possible :-))

> Note that this is about more than just validating and isn't about
> validators.

Yes, but "Conformance checkers that only perform validation" are, unless 
I am mistaken, validators.  Hixie, can you please clarify what that 
means, if I am mistaken?

Lachlan Hunt
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