Hi Trygve,

I apologize for any misunderstandings here. I am not an English native speaker. It was not my intent do accuse you of lying.

However, there is a difference between a bug report and an unsubstantiated rant. I did read your entire post "A Sad Day" as the latter. Whose mistake that was, I cannot tell now. Neutral, objective bug reports would read different, I suppose.

> I have copied the 2 methods below. The suspicious message is in 5.3: filteredEvent := child processEvent: localEvent using: self.  This assignment to a filter seems to be the root of the problem.

That's a bug then. I will investigate that. Morphs should be able to inject their own event dispatcher at any point during the dispatching. You'r observation is correct. We should fix that.

> Class MyConnector>> processEvent: anEvent using: anIgnoredDispatcher is a regular event handler in 3.10.2. In 5.3, it is a filter, and its execution never stops.

Reading "anIgnoredDispatcher" is misleading because that very method #processEvent:using: is actually talking to that "ignored" dispatcher. That's why I said, it's not true. It still is not true at that point in the code.

However, you made a valid point as written above. I will investigate that.

***

I am sorry that you had to use uppercase letters in your previous answer. You were screaming at me, I suppose. Well, it can sometimes be hard to form a substantiated, detailed answer to an abstract, high-level claim. I hope you can understand that. Sorry again.

We need better ways to assess the image quality.

We need better ways to post bug reports.

Best,
Marcel
Am 14.08.2020 11:01:38 schrieb Trygve Reenskaug <trygver at ifi.uio.no>:
Hi Marcel,
I am 90, and decided I did not want to spend the rest of my days with a Squeak I had no hope of understanding. That was the reason behind my goodbye-message where I was endeavoring to be as concrete and non-emotional as I possibly could. I then put everything Squeak in cold storage and picked up my life with other activities. Unfortunately, you wrote:

 Class MyConnector>> processEvent: anEvent using: anIgnoredDispatcher is a regular event handler in 3.10.2. In 5.3, it is a filter, and its execution never stops.
That's just not true.

I am deeply offended because you accuse me of lying. I reluctantly had to retrieve Squeak from its storage yesterday and spend most of the night awake trying to formulate a non-emotional answer. This is the result:

START FACTS
My Squeak Reverse Engineering program (SRE)  lets me build a diagram with nodes and connectors. I add new nodes interactively and the connectors are added automatically. The connectors behave as expected with the redbutton letting me add breakpoints to a connector line and the yellowbutton opens a menu as usual. SRE has been working for many years under Squeak 3.10.2 and has proven very useful.

I have copied and compiled the SRE classes into Squeak 5.3. I can still build a diagram with its nodes and connectors BUT the image freezes immediately if the cursor touches a connector. This anomaly is consistently reproducible and is a clear bug. I WAS NOT LYING!
END FACTS

I tried to debug the program. It was not easy because the normal debugging tools do not work in this case. My tentative findings were:

1)
The first error is a MNU: Your system believes my connector object is an event, which is isn't.

2)
MyConnector>> processEvent:using: is called from MorphicEventDispatcher, differently in the two releases:
3.10.2     MorphicEventDispatcher>>dispatchDefault: anEvent with: aMorph
5.3          MorphicEventDispatcher>>dispatchEvent: anEvent toSubmorphsOf: aMorph

I have copied the 2 methods below. The suspicious message is in 5.3: filteredEvent := child processEvent: localEvent using: self.  This assignment to a filter seems to be the root of the problem.

3.10.2>>MorphicEventDispatcher>>dispatchDefault: anEvent with: aMorph
    "Dispatch the given event. The event will be passed to the front-most visible submorph that contains the position wrt. to the event."
    | localEvt index child morphs inside |
    "See if we're fully outside aMorphs bounds"
    (aMorph fullBounds containsPoint: anEvent position) ifFalse:[^#rejected]. "outside"
    "Traverse children"
    index _ 1.
    morphs _ aMorph submorphs.
    inside _ false.
    [index <= morphs size] whileTrue:[
        child _ morphs at: index.
        localEvt _ anEvent transformedBy: (child transformedFrom: aMorph).
        (child processEvent: localEvt using: self) == #rejected ifFalse:[
            "Not rejected. The event was in some submorph of the receiver"
            inside _ true.
            localEvt wasHandled ifTrue:[anEvent copyHandlerState: localEvt].
            index _ morphs size. "break"
        ].
        index _ index + 1.
    ].
    "Check for being inside the receiver"
    inside ifFalse:[inside _ aMorph containsPoint: anEvent position event: anEvent].
    inside ifTrue:[^aMorph handleEvent: anEvent].
    ^#rejected

and

5,3>>MorphicEventDispatcher>>dispatchEvent: anEvent toSubmorphsOf: aMorph
    "Dispatch the given event to the submorphs of the given morph. For coordinate transformations, work only with copies. Either return the given event or a copy of any filtered event to employ immutability to some extent. --- PRIVATE!"
    | localEvent filteredEvent |   
    aMorph submorphsDo: [:child |
        localEvent := anEvent transformedBy: (child transformedFrom: aMorph).
        filteredEvent := child processEvent: localEvent using: self. "use same dispatcher"
        filteredEvent == #rejected ifFalse: [ "some event or #rejected symbol"
            self flag: #overlappingChildren. "mt: We cannot give two overlapping siblings the chance to handle the event!"   
            ^ self nextFromOriginal: anEvent local: localEvent filtered: filteredEvent]].
    ^ #rejected


The 5.3 version assigns the result of MyConnector>> processEvent:using: to a variable called filteredEvent. Nothing like that happens in 3.10.2, yet you claim that "The dispatcher is still dispatching as it was in Squeak 3.10.2". Since MyConnector>> processEvent:using: has never returned an event, the program is doomed to fail.

To avoid any further problems, I repeat that I am reporting to the best of my ability what I have experienced with a real program running in 2 real Squeak releases on real hardware. I also trust that the 2 methods i have quoted exist in the release images even though I have copied them from one of my debugging images.

I hope I can return everything Squeak back to its cold storage and that it will stay there.
Have fun and goodbye
--Trygve



On 2020-08-13 09:59, Marcel Taeumel wrote:

Hi Trygve.

> Class MorphicEventDispatcher has 4 methods in 3.10.2 and 16 methods in 5.3.

Finally, we managed to improve modularity of Squeak's event handling by assembling -- once scattered -- methods and logic in a place where it can be found and understood. Of course, the number of methods in a class can go up in the process. What you describe as "additional bloat" is clearly a revelation of already existing complexity.

Since the plain number of methods is rather unhelpful to assess code readability, I wonder whether there are better names we can use to guide programmers when exploring MorphicEventDispatcher, its protocols, and methods.

> Class MyMorph>> processEvent: anEvent using: anIgnoredDispatcher is a regular event handler in 3.10.2. In 5.3, it is a filter, and its execution never stops.

That's just not true. The dispatcher is still dispatching as it was in Squeak 3.10.2. Event filters were added as a mechanism to tackle the existing mis-use of event listeners. The filter mechanism uses patterns that are already existing in the Squeak system. Yes, there is still room for improvement regarding its modularity.

***

We need better ways to assess the image quality. Phrases such as "unbelievable image bloat", "many thousands of classes", etc. are not helpful at all. Such a perspective ignores incidental vs. accidental complexity. It also ignores the role of tools in such a live and exploratory programming system.

We need better ways to look beyond the source code. Of course, we strive for a clean, compact, understandable system. However, that goal must not only focus on lines of code, number of methods/classes/packages. Programmers do not just read code to gather understanding. They execute code, play around with objects ---> use tools. Those tools show us the names and relationships of all kinds of software artifacts. Those tools enable very concise, task-specific views on rather complex systems. Those tools can help find redundancy, clarify meaning.

Don't get me wrong. I am always in favor of removing a class or concept if that is not necessary. I do think twice before adding a new class or extending the inheritance tree.

However, just counting the number of code artifacts is not a helpful metric to move forward. It can only be a first step in a more throrough exploration process.

Don't give up. Happy Squeaking! :-)

Best,
Marcel
Am 13.08.2020 09:34:39 schrieb Trygve Reenskaug <trygver at ifi.uio.no> [mailto:trygver at ifi.uio.no]:

Dear All,
Imagine that you bought an iPhone 20 years ago. Over the years, you have filled it with pictures, contacts, and other personal data. You now want to upgrade to iPhone SE and find that all your personal data are lost because there is no way to transfer your data. Very sad.

The same has happened to me with Squeak. The Squeak programs I have written over the past 20 years are effectively lost because I can’t port them to a current version of Squeak. Very sad.

The essence of object orientation is that objects collaborate to achieve a goal. I retired 20 years ago and made it my task to create DCI (Data-Context-Interaction), a programming paradigm that merges the concepts of class and collaboration. BabyIDE is a non-intrusive Squeak program that includes a model of DCI as well as tools for programming within the paradigm. BabyIDE is a kind of Dynabook, a personal computer for experts in all domains. Its target group could be department managers in business and industry; they are experts in running their department in collaboration with other managers. Another target group could be farmers; they are experts in taking care of their animals. A third target group could be homeowners; they build expertise in controlling their smart home.

Squeak is more than a programming language; it is a live universe of collaborating objects. The shared objects on the web is also a universe of collaborating objects that Kevin Kelly called a single, global machine. BabyIDE extends the Squeak image into this global machine, making all the combined objects available for personal programming as illustrated below:




BabyIDE is now running in Squeak 3.10.2, together with a new Squeak Reverse Engineering tool. I want to port my programs to Squeak 3.5 to benefit from its improved internet communication facilities. This port has been pestering me since April, but the overwhelming complexity of 3.5 has forced me to accept defeat. I can’t avoid speculating about the nature of Squeak’s current target group. It used to be “children of all ages.” Today, it neither includes children nor old Smalltalk hands like me (I wrote my first Smalltalk program in 1978). Stephen Pope, another veteran who also bemoans what is happening to Squeak, wrote in a blog:


“The most popular systems (Squeak and Pharo) both suffer from unbelievable image bloat, with many thousands of classes, hundreds of root classes, class hierarchies with many instance variables in the high-level (abstract) classes, and too many packages with cute but meaningless (to a new-comer) names.”
https://smalltalk.tech.blog/2020/08/10/smalltalks-successor/ [https://smalltalk.tech.blog/2020/08/10/smalltalks-successor/]

I couldn’t agree more. A few examples:


1.   Class Object defines 485 methods. This means that every Squeak object understands at least 485 messages. Most of them are irrelevant to the problem at hand, but all of them can be part of unexpected behavior. 

2.   The state of every Morph object is held in its regular instance variables PLUS any number of undeclared and undocumented variables in its extension, a Dictionary that may include another dictionary inside it. The Morph class comment: “MorphExtension Allows extra properties to be stored without adding a storage burden to all morphs.” I’m more concerned about the burden put upon the code reader.

3.   For me, the final straw was the new filtering phase added to Squeak’s already complex event handling mechanism. Squeak 3.5 has 208 new methods with ‘filter’ in their name, but there is no indication as to what they are for and when to use them. The abstract concepts of event filtering are documented, but there is no documentation on their reification into concrete code. The complexity of a basically simple mechanism has reached a new high far beyond the capabilities of my brain.

4.   Class MorphicEventDispatcher has 4 methods in 3.10.2 and 16 methods in 5.3.

5.   Class MyMorph>> processEvent: anEvent using: anIgnoredDispatcher
is a regular event handler in 3.10.2. In 5.3, it is a filter, and its execution never stops.


After 60 years in programming, 42 of them in Smalltalk, and the last 20 in Squeak, I have reached the end of my patience and reluctantly have to quit Squeak programming. It is truly a sad day.

Have fun and Goodbye,
--Trygve


--

The essence of object orientation is that objects collaborate  to achieve a goal.
Trygve Reenskaug      mailto: trygver at ifi.uio.no [mailto:%20trygver at ifi.uio.no]
Morgedalsvn. 5A       http://folk.uio.no/trygver/ [http://folk.uio.no/trygver/]
N-0378 Oslo             http://fullOO.info [http://fullOO.info]
Norway                     Tel: (+47) 468 58 625


--

The essence of object orientation is that objects collaborate  to achieve a goal.
Trygve Reenskaug      mailto: trygver at ifi.uio.no [mailto:%20trygver at ifi.uio.no]
Morgedalsvn. 5A       http://folk.uio.no/trygver/ [http://folk.uio.no/trygver/]
N-0378 Oslo             http://fullOO.info [http://fullOO.info]
Norway                     Tel: (+47) 468 58 625
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