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Re: Language specification vs. user agent specification

From: Jonas Sicking <jonas@sicking.cc>
Date: Sun, 24 May 2009 14:42:26 -0700
Message-ID: <63df84f0905241442w3f727b69sbd230f603d0bf7eb@mail.gmail.com>
To: Larry Masinter <masinter@adobe.com>
Cc: HTML WG <public-html@w3.org>
On Sun, May 24, 2009 at 1:26 PM, Larry Masinter <masinter@adobe.com> wrote:
> Ian asked:
>> What do you mean by "a more traditional language definition" and why would
>> this be desireable?
> I think it is traditional to define a language and its semantics
> first -- what does an utterance in the language *mean* and separately
> and independently (even if the same document) define conformance
> requirements for processors of that language. The current document
> frequently does not do that, but defines the processing requirements
> and then infers the language semantics from that.
> I think this is why there are persistent discussions of it as a "browser spec"
> despite the attempts to define other conformance requirements.

For what it's worth I agree with this. There are advantages and
disadvantages with the current writing style IMHO. The main advantage
is that it makes it more likely for implementations to agree with each
other and have fewer bugs. This is definitely addressing an important
aspect, since implementation bugs and implementation differences is
one of the biggest problems facing web authors today. It's also a big
reason for why the web is as messy as messy as it is.

However it mostly helps with these things when the implementation is
able to follow the algorithm in the spec. In other cases the
implementation has to reverse engineer the semantics from the
algorithm and then create an implementation based on those semantics.
This introduces the risk of misinterpretations and bugs in both the
deducing semantics step, and the implementation step.

The other thing the current writing style helps with is that it's
unambiguous. This is another problem we've had with past W3C specs
leaving lots of things undefined leading to different implementations
in different UAs.

Ultimately while I generally agree that more of the spec should be
written by first describing semantic meaning and then implementation
algorithm, I think it's up to the editor to make the final decision.
And I'm definitely not going to argue one way or another without
having specific suggestions for what replace current text with.

/ Jonas
Received on Sunday, 24 May 2009 21:43:20 UTC

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