Can a function be passed to a component through a bind entry?

[jeffmath]

With a directive, I can pass a function into its isolate scope, using the '=' mode. Then, that function is callable from the directive's controller.
I am wanting to convert my directives to components.
After much trial and error, I have yet to determine how to pass a function into a component using an '=' entry in its bind dictionary. The docs for components only cover the '@' mode.
I am willing to pay you for an example of how to do this.