[whatwg] several messages

Ian Hickson ian at hixie.ch
Wed May 16 16:58:17 PDT 2007

On Wed, 16 May 2007, Darin Adler wrote:
> > > 
> > >     1) NANs
> > >     2) non-floating point values
> > >     3) missing parameters
> > > b) excess arguments
> > 
> > 1, 3, and b now raise exceptions except if otherwise specified. I 
> > haven't yet defined 2. I'm not sure what it should say.
> I think that (2) should be the same as (1). I think it makes logical 
> sense and matches current implementations. I'm not sure how it should be 
> presented or worded.

On Wed, 16 May 2007, Philip Taylor wrote:
> How is "non-floating point value" defined? Existing implementations seem 
> to try converting the value into a JS number, which will always give a 
> floating-point value, and that's just NaN if the conversion is not 
> possible (e.g. from an object, or undefined, or a string that can't be 
> parsed as a number). In that case, there aren't really non-floating 
> point values at all - there are just values that get numberised into NaN 
> before being passed to the canvas API and are then handled by case 1.
> http://canvex.lazyilluminati.com/misc/nonfloat.html sort of tests that 
> (though it just checks for exceptions, not for whether strings are 
> parsed into numbers properly) - it has no errors in Firefox (Minefield), 
> and in Opera 9.20 it only has errors for unimplemented functions and for 
> drawImage (bug?).

On Wed, 16 May 2007, Darin Adler wrote:
> Sounds great. If we can be clear that passing values to these properties 
> and functions does a numeric conversion that turns such things into NaN, 
> then all is well. I don't know where that rule should be stated.

Me either.

On Wed, 16 May 2007, Darin Adler wrote:
> I think that for (b) we should specify ignoring the additional 
> parameters rather than raising an exception. That's more consistent with 
> the behavior of the JavaScript language in general, and I'm pretty sure 
> all existing implementations do this.

On Wed, 16 May 2007, Philip Taylor wrote:
> http://canvex.lazyilluminati.com/misc/extra.html - Opera 9.20 ignores 
> all additional parameters, and Firefox ignores them except for drawImage 
> and for toDataURL (which is the one place where the spec explicitly says 
> extra parameters must be allowed - but FF uses them for privileged 
> content, and throws a security exception if normal content uses them).

I've changed the spec to say to ignore extra arguments and raise an 
exception for too few arguments.

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'

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