[syspec]

I'd rather just be able to mark an object as frozen, which we can already do.

JavaScript is adding so much new syntax I feel bad for people starting to learn the language now.

[jakelazaroff]

In terms of syntax this seems pretty lightweight, though. It's the same as instantiating a normal object or array, except with a hash in front.

[oweiler]

It's lightweight, but also looks obscure and will probably be hard to google.