ISSUE-16: Should the spec be silent or prescriptive re Object Identity

identity

Should the spec be silent or prescriptive re Object Identity

State:

CLOSED

Product:

Touch Events v1 spec

Raised by:

Matt Brubeck

Opened on:

2011-05-10

Description:

Should the Touch Events standard specify whether certain operations
return the same object?


Example 1: Should changedTouches and targetTouches refer to the same
objects as the "touches" attribute for the same event?

window.addEventListener("touchstart", function(e) {
var changedTouch = e.changedTouches[0];
var id = changedTouch.identifier;

var touch = e.touches.identifiedPoint(id);
var targetTouch = e.targetTouches.identifiedPoint(id);

// Should these be true?
assert(touch == changedTouch);
assert(touch == targetTouch);
});


Example 2: Should different touch events refer to the same objects?

window.addEventListener("touchstart", function(e0) {
var touch0 = e0.touches[0];
var id = touch.identifier;

window.addEventListener("touchmove", function(e1) {
var touch1 = e1.touches.identifiedPoint(id);
assert(touch0 == touch1); // Should this be true?
});
});


Leaving these implementation-defined might lead to content depending on
one behavior, and breaking if the implementation changes. For a similar
example, see:
http://www.quirksmode.org/blog/archives/2010/02/persistent_touc.html

Related Actions Items:

• ACTION-46 on Laszlo Gombos to Laszlo to follow-up re Object Identity implementation in WebKit - due 2011-05-17, closed
• ACTION-53 on Doug Schepers to Create a proposal to address issue-16 - due 2011-06-21, closed
• ACTION-54 on Arthur Barstow to Move issue-16 to Open - due 2011-06-21, closed
• ACTION-60 on Matt Brubeck to Propose spec text to address the resolution of issue-16 - due 2011-08-16, closed

Related emails:

1. Re: Input on ISSUE-16 (from mbrubeck@mozilla.com on 2011-09-02)
2. Draft minutes: 30 August 2011 call (from art.barstow@nokia.com on 2011-08-30)
3. Draft Agenda: 30 August 2011 (from art.barstow@nokia.com on 2011-08-29)
4. Re: Touch Events v1/v2 (from art.barstow@nokia.com on 2011-08-12)
5. Re: Touch Events v1/v2 (from art.barstow@nokia.com on 2011-08-12)
6. Re: Input on ISSUE-16 (from mbrubeck@mozilla.com on 2011-08-09)
7. Draft minutes: 9 August 2011 (from art.barstow@nokia.com on 2011-08-09)
8. Draft agenda: 9 August 2011 call (from art.barstow@nokia.com on 2011-08-08)
9. RE: Input on ISSUE-16 (from dzung.d.tran@intel.com on 2011-08-04)
10. Input on ISSUE-16 (from smoon@opera.com on 2011-08-03)
11. Canceled: Draft agenda: 2 August 2011 (from art.barstow@nokia.com on 2011-08-02)
12. Draft agenda: 2 August 2011 (from art.barstow@nokia.com on 2011-08-01)
13. Draft agenda: 26 July 2011 (from art.barstow@nokia.com on 2011-07-22)
14. Draft minutes: 19 July 2011 call (from art.barstow@nokia.com on 2011-07-19)
15. Draft agenda: 19 July 2011 call (from art.barstow@nokia.com on 2011-07-18)
16. Next call July 19 [Re: Seeking status of open action] (from art.barstow@nokia.com on 2011-07-11)
17. Seeking status of open action (from art.barstow@nokia.com on 2011-07-08)
18. Canceled: 28 June 2011 call ; next call on July 12 (from art.barstow@nokia.com on 2011-06-28)
19. Draft Agenda: 28 June 2011 (from art.barstow@nokia.com on 2011-06-27)
20. Draft Minutes: 21 June 2011 (from art.barstow@nokia.com on 2011-06-21)
21. Draft Agenda: 21 June 2011 call (from art.barstow@nokia.com on 2011-06-20)
22. Draft minutes: 14 June 2011 call (from art.barstow@nokia.com on 2011-06-14)
23. Draft agenda: 14 June 2011 call (from art.barstow@nokia.com on 2011-06-13)
24. Draft minutes: 7 June 2011 call (from art.barstow@nokia.com on 2011-06-07)
25. Draft Minutes: 24 May 2011 call (from art.barstow@nokia.com on 2011-05-24)
26. Draft agenda: 24 May 2011 call (from art.barstow@nokia.com on 2011-05-23)
27. Re: Draft minutes: 10 May 2011 call (from smoon@opera.com on 2011-05-11)
28. Draft minutes: 10 May 2011 call (from art.barstow@nokia.com on 2011-05-10)
29. ISSUE-16: Should the spec be silent or prescriptive re Object Identity (from sysbot+tracker@w3.org on 2011-05-10)

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