A better way to define readonly properties ?

Current solution involves a lot of boilerplate code:

``` typescript
class A {
 constructor(a: number) {
  this._a = a;
 }

 private _a: number;
 get a(): number { return _a; }
```

It would be nice to have something simpler.
Now you can define properties from the constructor, why not define getter there as well ?

``` typescript
class A {
 constructor(get a: number) {
 }
```
