Actions

Provides methods to delay arbitrary code ("actions") and to execute the delayed actions later in FIFO order.

When delayed code is eventually executed, its resulting value will be discarded so the delayed code should be effectful.

The point of this delay is to avoid potential initialization-order bugs inside the homework object (object hw7 extends ...) that would otherwise be very confusing for students. For example, a test might indirectly depend on a val that has not yet been initialized. Instead, the test will delayed--invisibly to the student--to be executed inside the main method, after object initialization is complete.

class Object

trait Matchable

class Any

class hw

Value members

Concrete methods

Delays arbitrary code to be executed later by runActions.

The delayed code from multiple calls to registerAction will be executed in FIFO order. Because of this FIFO order, nested calls of registerAction may behave in unexpected ways, especially when recursion is involved.

Note that values produced by the delayed code are discarded, so such code should always be effectful. Contrariwise, any effectful code in the body of a normal homework should usually be wrapped a registerAction.

Value parameters:

action: arbitrary code to be executed later