On 31 May 2012 11:18, T.J. Crowder <[email protected]> wrote: > On 31 May 2012 11:05, Jussi Kalliokoski <[email protected]>wrote: > >> On Thu, May 31, 2012 at 12:52 PM, T.J. Crowder >> <[email protected]>wrote: >> >>> On 31 May 2012 10:44, Andreas Rossberg <[email protected]> wrote: >>> >>>> On 30 May 2012 23:34, David Herman <[email protected]> wrote: >>>> > On May 30, 2012, at 2:27 PM, Rick Waldron wrote: >>>> > >>>> > On Wed, May 30, 2012 at 5:22 PM, David Herman <[email protected]> >>>> wrote: >>>> >> >>>> >> >>>> >> array.{ >>>> >> pop(); >>>> >> pop(); >>>> >> pop(); >>>> >> }; >>>> >> >>>> >> path.{ >>>> >> moveTo(10, 10); >>>> >> stroke("red"); >>>> >> fill("blue"); >>>> >> ellipse(50, 50); >>>> >> }; >>>> >> >>>> >> this.{ >>>> >> foo = 17; >>>> >> bar = "hello"; >>>> >> baz = true; >>>> >> }; >>>> > >>>> > >>>> > This is beautiful and looks powerful -- will it still meet the most >>>> > common/obvious use case? >>>> > >>>> > var div = document.createElement(). >>>> > >>>> > div.{ >>>> > style.{ >>>> > color = "red"; >>>> > left = "100px"; >>>> > } >>>> > }; >>>> > >>>> > >>>> > I didn't specify in my blog post. :) I'm open to it. I tend to find >>>> the >>>> > nested syntax a little brain-exploding, but I understand the >>>> motivation. >>>> >>>> Assuming you propose to allow things like o.{a.b = 6; c.f()} anyway, >>>> then the above would actually fall out for free if you defined your >>>> syntax as pure syntactic sugar, and do the rewriting in the natural >>>> bottom up manner. >>>> >>>> /Andreas >>> >>> >>> I'm worried this looks a lot like `with` -- with the same issues. Is the >>> idea that unqualified references would be _required_ to be properties of >>> the object in question? So >>> >> >> I actually thought that this looks like `with` as well, but I don't share >> your concerns, to me this looks like a fixed `with`. >> >> >>> o.{ >>> a.b = 6; >>> c.f(); >>> }; >>> >>> ...would work, but >>> >>> o.{ >>> a.b = foo; >>> c.f(); >>> }; >>> >>> ...would throw (assuming there is no `foo` property)? >>> >> >> I don't see a reason why it wouldn't throw, if I understood correctly. I >> don't see why `foo` should have anything to do with `o`. IMHO, it's best if >> only the left-hand side interacts with the object being extended, this way >> we don't get the problems of `with`, i.e. scope being (near-)impossible to >> measure and more minorly, easy leaked globals (e.g. var a = {}; with (a) { >> foo = 'bar' } ). >> >> Cheers, >> Jussi >> > > So the idea is that only the left-hand side has the magic. Except that > there doesn't always seem to _be_ a left-hand side (ref `c.f()` above), > which makes this look at lot like some kind of block rather than a batch > assignment/definition (since things aren't always being assigned/defined), > and thus a lot like `with`. > > If we start introducing calls as well as assignments and property > definitions. When things start looking like a series of statements, I'm > worried we'll start reading them that way, and get things like this: > > o.{ > a.b = 6; > c.f(); > a.b = a.c; // !! > }; > > The expectation there (the last line) would surely be that both `a`s refer > to the same thing. This problem exists now (and sometimes comes up) with > regard to object literals, but object literals don't look much like a > series of statements. This does. > > -- T.J. >
I should clarify here that I don't think the current strawman allows that `c.f()` line. It's something that's been raised in this thread. -- T.J.
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