Sorry about what my code formatter is doing to the rect element in the above.
I can then open the result in iDraw, scale the drawing down to the appropriate size for an iOS icon and save it out as a PNG. For smaller icon sizes, 29 pixels? really?, I might tweak it a bit to emphasize just one sub-element. The advantage for me is I get exactly what I expect with mathematically pure shapes. And it's a lot simpler than the times I've programmed graphics in raw Postscript. It wouldn't necessarily be a good way to make an elaborately textured icon, but with the flat simplicity mantra of iOS 7 the stark clean lines of SVG are a good fit.
Oh, and here's an animated GIF my new app can generate of me drawing the icon: