Dear Pharo community,

I am happy to present a new tool designed specifically for comparing classes in Pharo. It provides a two-sided list of methods, so you can quickly understand the relationships between two classes.

The project location is on GitHub:

https://github.com/hernanmd/class-diff

Feel free to send comments and contributions via PRs.
Have a great day,

Hernán

Dear Pharo community,

I am happy to present a new tool designed specifically for comparing classes in Pharo. It provides a two-sided list of methods, so you can quickly understand the relationships between two classes.

The project location is on GitHub:

https://github.com/hernanmd/class-diff

Feel free to send comments and contributions via PRs.
Have a great day,

Hernán

This looks interesting, and I will definitely check it out.

As a small side query - i've noticed a few times now that people are
giving load instructions like :

EpMonitor disableDuring: [
Metacello new

I understand that this de-clutters the work history, so its much easier
track real changes - however why isn't there an extension on Metacello in
Pharo, that does this automatically - e.g.  #loadWithoutLogging ?

Then everyones instructions could be much cleaner - and this extension
might also do something clever to log that you loaded a baseline - but not
show all the code loaded?

I'm curuious on this - and possibly its PR we should submit?

Tim

On Mon, 22 Jul 2024, at 7:57 AM, Hernán Morales Durand wrote:

Dear Pharo community,

I am happy to present a new tool designed specifically for comparing
classes in Pharo. It provides a two-sided list of methods, so you can
quickly understand the relationships between two classes.

The project location is on GitHub:

https://github.com/hernanmd/class-diff

Feel free to send comments and contributions via PRs.
Have a great day,

Hernán

Thanks for your nice feedback Richard, I will sketch something and see how it goes.

About learning Spec2, for me, the best resource is to directly use the image examples. In the main menu, you have "Help -> Spec 2 demo" and "Help -> Spec 2 examples". And you also have the book in https://github.com/SquareBracketAssociates

Hernán

El mar, 23 jul 2024 a las 10:30, Richard O'Keefe (raoknz@gmail.com) escribió:

That's a very nice tool.  There are two tweaks I'd like to see.
Two classes having methods with the same name isn't the same as two
classes having the same method.
When the two classes have a method with the same name, there are at
least three possibilities:

• The methods are the same method

• The methods are different, but the name is defined in some common
  superclass, so they had better be related methods.

• The methods are completely unrelated, like #next in ReadStream and LIFOQueue.

The third case applies to every method.  Perhaps the best way
therefore is to show
something in the header, like

(score) diff of descendants of <nearest common superclass>
<column> <column>

The first and second cases are the ones I want to tell apart so that I
don't spend any time looking
for differences that aren't there.

What's the best way to learn how to use Spec2?

On Mon, 22 Jul 2024 at 18:58, Hernán Morales Durand
hernan.morales@gmail.com wrote:

Dear Pharo community,

I am happy to present a new tool designed specifically for comparing classes in Pharo. It provides a two-sided list of methods, so you can quickly understand the relationships between two classes.

The project location is on GitHub:

https://github.com/hernanmd/class-diff

Feel free to send comments and contributions via PRs.
Have a great day,

Hernán

Thanks for the advice about Spec2.
I was keen to try Class-diff out, so I fired up Pharo, followed the
installation instructions with no problems, and then tried the
example.
The example got a run-time error, and I expect that it's because the
Pharo release I fired up was Pharo 9.

Which release(s) of Pharo is Class-diff intended to work with?

On Tue, 23 Jul 2024 at 23:38, Hernán Morales Durand
hernan.morales@gmail.com wrote:

Thanks for your nice feedback Richard, I will sketch something and see how it goes.

About learning Spec2, for me, the best resource is to directly use the image examples. In the main menu, you have "Help -> Spec 2 demo" and "Help -> Spec 2 examples". And you also have the book in https://github.com/SquareBracketAssociates

Hernán

El mar, 23 jul 2024 a las 10:30, Richard O'Keefe (raoknz@gmail.com) escribió:

That's a very nice tool.  There are two tweaks I'd like to see.
Two classes having methods with the same name isn't the same as two
classes having the same method.
When the two classes have a method with the same name, there are at
least three possibilities:

• The methods are the same method

• The methods are different, but the name is defined in some common
  superclass, so they had better be related methods.

• The methods are completely unrelated, like #next in ReadStream and LIFOQueue.

The third case applies to every method.  Perhaps the best way
therefore is to show
something in the header, like

(score) diff of descendants of <nearest common superclass>
<column> <column>

The first and second cases are the ones I want to tell apart so that I
don't spend any time looking
for differences that aren't there.

What's the best way to learn how to use Spec2?

On Mon, 22 Jul 2024 at 18:58, Hernán Morales Durand
hernan.morales@gmail.com wrote:

Dear Pharo community,

I am happy to present a new tool designed specifically for comparing classes in Pharo. It provides a two-sided list of methods, so you can quickly understand the relationships between two classes.

The project location is on GitHub:

https://github.com/hernanmd/class-diff

Feel free to send comments and contributions via PRs.
Have a great day,

Hernán

OK, so I tried Class-diff in Pharo 11.  I noticed two issues.
(1) I expected it to work like kdiff3, where scrolling scrolls both panes.
I'm so used to flying around differences using
Next/Previous/Last/First Difference buttons that I do very little
scrolling in kdiff3, but when I do scroll, it does its best to keep
the two panes aligned.
(2) Comparing Array and String, I eventually figured out that I was
being shown selectors defined in each class, but no selectors
inherited by a class.  For example, String canUnderstand: #asArray
but inherits it, so it's not shown in the String pain, while Array
defines it.  This looks like a "one class has it and the other lacks
it" case but it's *actually" a "both classes have it and it's
different in each", so a difference I'd really like to see.
I tracked this down to
self aligner
align: self sourceClass selectors sort
with: self targetClass selectors sort.
in updateAlignment,  Changing that to
self aligner
align: self sourceClass allSelectors asArray sort
with: self targetClass allSelectors asArray sort
got me closer to what I wanted, but then accessing the source code of
inherited methods didn't work because inherited methods, by
definition, aren't in the class's own method dictionary.  I could work
around that too, but it's 1:19 AM where I am.  In fact that's not
quite what I want anyway.  I don't want to be shown methods inherited
by both classes from Object (although methods inherited from Object
by one class and redefined or inherited from another class by the
other are ones I do want to see).

On Wed, 24 Jul 2024 at 14:06, Richard O'Keefe raoknz@gmail.com wrote:

Thanks for the advice about Spec2.
I was keen to try Class-diff out, so I fired up Pharo, followed the
installation instructions with no problems, and then tried the
example.
The example got a run-time error, and I expect that it's because the
Pharo release I fired up was Pharo 9.

Which release(s) of Pharo is Class-diff intended to work with?

On Tue, 23 Jul 2024 at 23:38, Hernán Morales Durand
hernan.morales@gmail.com wrote:

Thanks for your nice feedback Richard, I will sketch something and see how it goes.

About learning Spec2, for me, the best resource is to directly use the image examples. In the main menu, you have "Help -> Spec 2 demo" and "Help -> Spec 2 examples". And you also have the book in https://github.com/SquareBracketAssociates

Hernán

El mar, 23 jul 2024 a las 10:30, Richard O'Keefe (raoknz@gmail.com) escribió:

That's a very nice tool.  There are two tweaks I'd like to see.
Two classes having methods with the same name isn't the same as two
classes having the same method.
When the two classes have a method with the same name, there are at
least three possibilities:

• The methods are the same method

• The methods are different, but the name is defined in some common
  superclass, so they had better be related methods.

• The methods are completely unrelated, like #next in ReadStream and LIFOQueue.

The third case applies to every method.  Perhaps the best way
therefore is to show
something in the header, like

(score) diff of descendants of <nearest common superclass>
<column> <column>

The first and second cases are the ones I want to tell apart so that I
don't spend any time looking
for differences that aren't there.

What's the best way to learn how to use Spec2?

On Mon, 22 Jul 2024 at 18:58, Hernán Morales Durand
hernan.morales@gmail.com wrote:

Dear Pharo community,

I am happy to present a new tool designed specifically for comparing classes in Pharo. It provides a two-sided list of methods, so you can quickly understand the relationships between two classes.

The project location is on GitHub:

https://github.com/hernanmd/class-diff

Feel free to send comments and contributions via PRs.
Have a great day,

Hernán