MorphicEventHandler behavior.

Steph, 

I was looking and in the end of #buildKeyboard you have:

self submorphsDo:
                [:m | m on: #mouseMove send: #mouseMovePitch:event:noteMorph: to: self;
                                on: #mouseUp send: #mouseUpPitch:event:noteMorph: to: self;
                                on: #mouseEnterDragging send: #mouseDownPitch:event:noteMorph: to: self;
                                on: #mouseLeaveDragging send: #mouseUpPitch:event:noteMorph: to: self].

Which create subscriptions without any value. And that's why you get the nil and the DNU.

It probably was working in 1.4 because the EventHandler code did only manage one subscription at a time and probably didn't notice these last subscriptions.

Now int 2.0 all subscriptions to events are handled, and that's the reason of the DNU.

I tested the code without that statement and get it work..

Guille

On Sun, Mar 10, 2013 at 11:01 AM, Stéphane Ducasse <[hidden email]> wrote:

Hi fernando

May be you know more than me on MorphicEventHandler.

Gofer new
         squeaksource: 'PharoNonCorePackages';
        package: 'Sound';
        package: 'SoundMorphicUserInterface';
        load.



While trying to make
        PianoKeyboardMorph new openInWorld
        (which works in 1.4 and does not in 20).

It breaks here:

-------------
mouseUpPitch: pitch event: event noteMorph: noteMorph

        noteMorph color: ((#(0 1 3 5 6 8 10) includes: pitch <a href="smb://12">\\12)
                                        ifTrue: [whiteKeyColor]
                                        ifFalse: [blackKeyColor]).
        soundPlaying ifNotNil: [soundPlaying stopGracefully].

pitch is nil because notify:from: uses valueParameter which is nil.
-------------

mouseUpPitch is invoked by notify: anEvent from: sourceMorph which is invoked by notifyMorphsOfEvent: anEvent ofType: eventType from: sourceMorph

notify: anEvent from: sourceMorph
        | arity |
        recipient ifNil: [^ self].
        arity := selector numArgs.
        arity = 0 ifTrue:
                [^ recipient perform: selector].
        arity = 1 ifTrue:
                [^ recipient perform: selector with: anEvent].
        arity = 2 ifTrue:
                [^ recipient perform: selector with: anEvent with: sourceMorph].
        arity = 3 ifTrue:
                [^ recipient perform: selector with: valueParameter with: anEvent with: sourceMorph].
                                                                        ^^^^^^^^^^^^^^^^^^^^^^^
        self error: 'Event handling selectors must be Symbols and take 0-3 arguments'

notifyMorphsOfEvent: anEvent ofType: eventType from: sourceMorph
        | result |
        result := false.
        ((subscriptions includesKey: eventType) not or: [ (subscriptions at: eventType) isEmpty ])
                ifTrue: [ ^false ].
        (subscriptions at: eventType) do: [ :s | result := result | ((s notify: anEvent from: sourceMorph) == true) ].
                                                                                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

        ^result


The idea is that morphs get notified when a certain event occurs so when we look at the morph creation and event registry we get:


The buildKeyboard create morph and define event with a given value that will be used
        on: #mouseDown send: #mouseDownPitch:event:noteMorph: to: self withValue: i-1*12 + (#(2 4 7 9 11) at: j)
below:


buildKeyboard
        | wtWid bkWid keyRect octavePt nWhite nBlack |
        self removeAllMorphs.
        wtWid := 8. bkWid := 5.
        self extent: 10@10.
        1 to: nOctaves+1 do:
                [:i | i <= nOctaves ifTrue: [nWhite := 7.  nBlack := 5]
                                                ifFalse: [nWhite := 1.  nBlack := 0 "High C"].
                octavePt := self innerBounds topLeft + ((7*wtWid*(i-1)-1) @ -1).
                1 to: nWhite do:
                        [:j | keyRect := octavePt + (j-1*wtWid@0) extent: (wtWid+1)@36.
                        self addMorph: ((RectangleMorph newBounds: keyRect color: whiteKeyColor)
                                                                borderWidth: 1;
                                on: #mouseDown send: #mouseDownPitch:event:noteMorph: to: self
                                                                withValue: i-1*12 + (#(1 3 5 6 8 10 12) at: j))].
                1 to: nBlack do:
                        [:j | keyRect := octavePt + ((#(6 15 29 38 47) at: j)@1) extent: bkWid@21.
                        self addMorph: ((Morph newBounds: keyRect color: blackKeyColor)
                                on: #mouseDown send: #mouseDownPitch:event:noteMorph: to: self
                                                                withValue: i-1*12 + (#(2 4 7 9 11) at: j))]].
        self submorphsDo:
                [:m | m on: #mouseMove send: #mouseMovePitch:event:noteMorph: to: self;
                                on: #mouseUp send: #mouseUpPitch:event:noteMorph: to: self;
                                on: #mouseEnterDragging send: #mouseDownPitch:event:noteMorph: to: self;
                                on: #mouseLeaveDragging send: #mouseUpPitch:event:noteMorph: to: self].
        self extent: (self fullBounds extent + borderWidth - 1)



Now I can understand that
        #mouseDownPitch:event:noteMorph: get notified with a value because this is what is written.
But I do not get why this would be the case with #mouseUpPitch:event:noteMorph:
since we simply get
        on: #mouseUp send: #mouseUpPitch:event:noteMorph: to: self;


And I do not get why this was working in 1.4