Eventable and Evented no longer include #hooksEvent

This is introspection, which can be provided elsewhere or by specific
implementations. Together with the documented requirement (in Eventable#on)
that listeners must be notified of automatic un-hooking, and that systems
handling listeners will always be aware of when listeners are
hooked/unhooked, this method should not be necessary.

Including this method in Eventable also introduces incompatibility with
Node.js' Event API, which is undesirable.

src/event/Eventable.js

@@ -106,27 +106,6 @@ module.exports = Interface( 'Eventable',
     addListener: [ 'ev', 'listener' ],
 
 
-    /**
-     * Determine whether LISTENER is listening for messages emitted by event
-     * EV
-     *
-     * If event EV is not valid, either `false` shall be returned or
-     * an error shall be thrown, since LISTENER cannot possibly hook an
-     * invalid event.
-     *
-     * This method is not intended as an introspective/reflection
-     * mechanism---it allows a consumer of an Eventable object to determine
-     * whether LISTENER has already been hooked before blindly
-     * hooking/unhooking it.
-     *
-     * @param {string}   ev       event id
-     * @param {Function} listener listener to query for
-     *
-     * @return {boolean} whether LISTENER hooks event EV
-     */
-    hooksEvent: [ 'ev', 'listener' ],
-
-
     /**
      * Unhook LISTENER from event EV, preventing further messages from being
      * received

src/event/Evented.js

@@ -296,7 +296,7 @@ module.exports = Trait( 'Evented' )
      *
      * @return {boolean} whether LISTENER hooks event EV
      */
-    hooksEvent( ev, listener )
+    'protected hooksEvent'( ev, listener )
     {
         let levdata = listener[ this._evid ];
         return !!( levdata && ( levdata[ ev ] !== undefined ) );

test/event/EventedTest.js

@@ -617,55 +617,6 @@ describe( 'event.Evented', () =>
     } );
 
 
-    describe( '#hooksEvent', () =>
-    {
-        var ev = 'foo',
-            f;
-
-        beforeEach( () =>
-        {
-            // ensure fresh listener
-            f = () => {};
-        } );
-
-
-        it( 'recognizes listener for a hooked event', () =>
-        {
-            stub.evDefineEvents( [ ev ] )
-                .on( ev, f );
-
-            expect( stub.hooksEvent( ev, f ) ).to.be.true;
-        } );
-
-
-        it( 'does not recognize listener for non-hooked event', () =>
-        {
-            expect( stub.hooksEvent( ev, f ) ).to.be.false;
-        } );
-
-
-        /**
-         * Technically this test is sufficient to make the previous two
-         * redundant, but they are retained for clairty in debugging.
-         */
-        it( 'does not recognize listeners of other events', () =>
-        {
-            var ev2 = 'bar',
-                f2  = () => {};
-
-            stub.evDefineEvents( [ ev, ev2 ] )
-                .on( ev, f )
-                .on( ev2, f2 );
-
-            expect( stub.hooksEvent( ev, f ) ).to.be.true;
-            expect( stub.hooksEvent( ev2, f ) ).to.be.false;
-
-            expect( stub.hooksEvent( ev, f2 ) ).to.be.false;
-            expect( stub.hooksEvent( ev2, f2 ) ).to.be.true;
-        } );
-    } );
-
-
     describe( 'listener metadata', () =>
     {
         /**