Two interoperable implementations rule
mjs at apple.com
Fri Jul 11 16:10:43 PDT 2008
On Jul 11, 2008, at 3:49 PM, Jeff Dyer wrote:
> On 7/11/08 3:01 PM, Maciej Stachowiak wrote:
>> 2) How is interoperability to be demonstrated? Do we accept good-
>> claims of support, or do we need a test suite?
> I'd say that good faith is good enough. It's easy enough for us to
> each other's work. And the blogosphere will not be kind to liars.
I'm less concerned about cheating than about honest mistakes, which
may nonetheless affect interoperability, Web compatibility, or
practical implementability of the spec.
For the WebKit project, we always make our best effort to correctly
implement Web standards, and even make our own test cases as we go.
However, once an independently developed test suite appears it always
finds mistakes in our implementation. I think we are not unusual in
> One more detail:
> 3) What constitutes a qualifying implementation? Does Rhino, EJScript
> (mbedthis.com), or Flash Player qualify? Or must it be one of the four
> leading browsers?
That is a good point to raise. I think limiting to browser-hosted
implementations might be too extreme. On the other hand, if a spec
qualifies based solely on non-browser-hosted implementations, then we
have not done much to verify that the standard is compatible with the
real-world Web. I think a reasonable middle ground would be to require
at least one of the implementations to be browser-hosted. For these
purposes, I would count an implementation that works as a browser
extension replacing the scripting engine so long as it actually gets
wide testing, so for example ScreamingMonkey could qualify.
It should also be required that the two implementations are
independent (so a single vendor presenting two implementations would
not qualify). This may be tricky to define, since many possible
candidate implementations are open source and developed
collaboratively by community contributors and overlapping sets of
vendors. For example, would Rhino and SpiderMonkey count as
sufficiently independent implementations?
>> Given the nature of programming languages and the high stakes of Web
>> standards, I would personally prefer whole-spec granularity
>> implementations having different mixes of features does not prove
>> interoperability), and a test suite rather than just bare claims of
> Again, it will be hard to get away with cheating. But, on the other
> hand an
> unofficial test suite (such as Spidermonkey's) would make it easier
> implementors to be honest.
Again, I am less worried about cheating than mistakes. If we had a
semi-official test suite, it would not be normative, only the spec is
normative. It would only be a tool for verifying interoperability has
been achieved to a reasonable degree. The concern is less about
deliberate deception than about having at least the minimal evidence
needed to make a fact-based claim.
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