support for decorators syntax

[HairyRabbit]

link examples

typescript/decorators
tc39/proposal-decorators

syntax

basic syntax

@a @1+1 @c(d) class Foo {}
// or
@a
@1+1
@c(d)
class Foo {}

class decorators

@a class Foo {}

class method decorators

class Foo {
  @a
  b() {}
  @c
  get d() {}
}

class prop decorators

class Foo {
  @a
  b: number = 42
}

class method params decorators (maybe not easy to implement)

class Foo {
  @a
  b(@c d, e) {}
}