Hi Lauren,

I am a big fan of Common Lisp conditions and restarts. Just as mentioned I
too already mused on the list once that the debugger notifier buttons like
Proceed and Abandon could be generalized in this way.

However, they are not Smalltalk "standard" (not even de facto), therefore
not portable, and you must expect that they do not get widely adopted even
in the Squeak community (how many of us use Traits?!). I could see them
being used as a Squeak-internal feature though, like for the debugger
buttons... And I would like to use them for some error recovery cases in
the Git Browser if they were already there.

About increasing the complexity of the system, I am torn. In Cuis, restarts
would probably have no place for that reason, unless the
learning/understanding impact is really small. Maybe it would be good to
see first how much more complicated things get with a restarts mechanism in
place. But that may be well after you or anyone else has already invested
most of the work.

So, I would be delighted to see this happen. But I also do not want to
incite any illusions. ;-)

Kind regards,
Jakob



Lauren P <drurowin at gmail.com> schrieb am Mo., 28. Nov. 2022, 17:49:

> Hi List,
>
> In reference to my question about the debugger in regards to
> Chronology-Core-dtl.80, I have a proposal.
>
> I am halfway or so to stealing RESTART from Common Lisp for Squeak.  It
> lets the programmer define alternatives for exception handling.  Restarts
> would be responsible for making the Proceed, Abandon, etc. buttons in the
> debugger window, with every #on:offer: defining a button.
>
> It's an extra layer of indirection and complexity in the evaluator, but it
> is an extremely powerful tool for writing clean code.  If I had to choose
> one of an interactive debugger or restarts I'd pick restarts.
>
> Implementation is easy but tedious... restarts have lots of optional
> parameters.  If List thinks RESTART would be a good thing to have I will
> prioritize it.
>
> PS: Whoever wrote the signalling code, thank you.  It is very clean and
> easy to read.  I learned everything about dynamic extent in Smalltalk from
> reading it.
>
> --
> Obviously, I vote yes, and the effort to not proselytize the Cult Of
> Restart here is great indeed.
>
>
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