On Nov 10, 2011, at 7:59 AM, Mark S. Miller wrote: > My previous proposal for class-like sugar for traits composition was not > popular. Whereas, in the absence of problem #5, I suspect the traitsjs > library would be. As previously observed on this list, traitsjs is more > JavaScripty. Ideal would be for JSVMs to magically make traitsjs efficient > without requiring any language changes. If this is infeasible, perhaps we > should instead be looking for the minimal language change that would enable a > revision of traitsjs to run efficiently on ES-nest-next JSVMs.
The http://brendaneich.com/2011/01/harmony-of-my-dreams/#sharp_functions proposal, while out of date now, did try to support concise joined/frozen functions, joined up to the nearest relevant closure. If that is the constructor, you still have a sharp function per method per instance, but if the methods use only |this| and their parameters. How HoBD sharp functions handle |this| was not totally clear. We talked at the January meeting about supporting only lexical |this|, only caller |this|, and (perhaps in March) "soft binding" where lexical |this| is the default but it can be overridden by caller |this|. > I say ES-next-next because it is too late to consider any such language > change for ES-next. However, implementation experiments need not wait. To revive the HoBD sharp-function idea at this point, I would want to get tenative agreement on |this|-binding. Your thoughts welcome. /be > > > On Thu, Nov 10, 2011 at 7:19 AM, Andreas Rossberg <[email protected]> wrote: > [...] > No, that's how it works right now. The alternative is to lexically > close all methods over self at construction time: > > function Point(x, y) { > var self = this > self.x = x > self.y = y > self.move = function(dx, dy) { self.x += dx; self.dy += dy } > } > > function ColorPoint(x, y, color) { > var self = this > Point.call(self, x, y) > self.color = color > self.recolor = function(c) { self.color = c } > } > > As said, this doesn't play well with prototype inheritance. You have > to put all methods that refer to self on the object itself. But "inner > constructors" are straighforward and safe. > -- > Cheers, > --MarkM
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