On 2012-09-16 23:40, David Greenspan wrote:
6.2 - "... first matching Element node within the subtrees..."
Don't define a new term "subtrees" which just means "descendants." Say,
"... first matching Element node that is a descendant of the context
object."
I could do that, but doing so makes it harder to rephrase this statement
without making it more complex.
3. The implementation must then run the algorithm to evaluate a
selector against element nodes in the specified tree or subtrees
using parsed selector as the selector and reference nodes as the
contextual reference element set, as needed to return the required
result for the invoked method.
If you have a suggestion for how to rephrase that to remove "subtrees"
in a readable way without altering the meaning, please let me know.
The main take-away from section 6.2 should be that find/findAll use a
*different algorithm* from querySelector/querySelectorAll, or the same
algorithm with a different setting (relative=true). This point is almost
entirely lost.
I think the clearest of those two alternatives is to clearly separate
the two algorithms. I have made this change in the spec.
I think the intent is for the reader to perform a sort of
"dispatch on type" when the algorithm in 6.5 is invoked, but it's confusing
because you can't really look at a selector and a relative selector and
tell them apart, and certainly not before parsing them.
The intent was that the reader is supposed to know whether you have a
selector or relative selector based on which method was invoked. The
above changes now make that clearer.
6.2 - "When either method is invoked..." - there are four methods, not 2
Good point, but with the above changes, I also made it more explicit
about which methods are being referred to in each case.
6.5 - "... begins with a combinator and that combinator is not ' ' (space)"
- how can a relative selector, in a comma-separated list with whitespace,
physically start with a space, i.e. a descendant combinator??
This was added to clarify that ' ' is excluded from the set of possible
combinators that trigger automatic prepending of :scope, regardless of
whether the selector meets any of the other conditions. At this stage
in the algorithm, no whitespace has been trimmed from the selector, so
if the input is " div", then it needs to be clear that :scope is not
prepended in step 1.
Note that there is a known bug in the way the grammar is defined that
does actually allow for a relative selector to begin with a descendant
combinator. I just haven't figured out a good way to fix this. I have
now noted this issue in the spec.
Supposing it can (at the beginning of the string, perhaps), why would
you special-case
it and prepend what's presumably a second descendant combinator in step 5?
Because if steps 2, 3 or 4 apply, then step 5 doesn't apply and :scope
is not prepended.
e.g.
document.find(" div"); // Matches condition in step 2
elm.find(" not(:scope)"); // Matches condition in step 3
elm.find(" body.foo :scope p"); // Matches condition in step 4
If space was not excluded, the the spec could be interpreted such that
:scope should be prepended in those cases.
7 - "contextual reference element" - This term is revealed to mean simply a
potential :scope element. I would call it something like a "scope
candidate" -- or basically anything besides what it's called.
This section was intended to be dropped now that Selectors 4 defines
:scope adequately, and as such the term "contextual reference element"
has been removed. However, the term "contextual reference element set"
still remains due to its definition in Selectors 4. If you wish to have
that changed, please follow this up with the CSS WG.
I have now removed section 7 "The :scope Pseudo-class" entirely from
this spec.
8 - Feature Strings - Change last paragraph to: "Conforming implementations
must return true ... if they are perfectly compliant, and false if they are
not."
No. Feature strings are a notoriously unreliably method of determining
support for a given feature and it only exists to provide an indication
that there is some support for the API, without specifying how compliant
a given implementation is.
9 - Examples of find() and :scope MUST be added here. Seriously. This
section is the last chance to push that lucky reader over the final
threshold to feeling like they fully understand the spec.
They will be added in due course. They hadn't been added yet due to the
prior instability of the new API design and their low priority. However,
feel free to contribute some examples if you like and I will consider
including them.
--
Lachlan Hunt - Opera Software
http://lachy.id.au/
http://www.opera.com/
