swizzle.js

gistfile1.js

/* 
   assumes you put your constructors for vec2,vec3,etc on your prototype or in global scope
   because the Function constructor will move the scope of the getters & setters to the global scope
   if you don't care about a bunch of closures you could also just use normal functions.
*/
["x","y","z"].map(function(ex,x,a){
    Object.defineProperty(vec3.prototype,a[x],{
        get:new Function("return this["+x+"];"),
        set:new Function("v","this["+x+"] = v;")
    });
    return a.map(function(ey,y){
        Object.defineProperty(vec3.prototype,a[x]+a[y],{
            get:new Function("return new this.vec2(this["+x+"],this["+y+"]);"),
            set:new Function("v","this["+x+"]=v[0];this["+y+"]=v[1];")
        });
        return a.map(function(ez,z){ 
            Object.defineProperty(vec3.prototype,a[x]+a[y]+a[z],{
                get:new Function("return new this.vec3(this["+x+"],this["+y+"],this["+z+"]);"),
                set:new Function("v","this["+x+"]=v[0];this["+y+"]=v[1];this["+z+"]=v[2];")
            })
        })
    })
});