[Pharo-project] About announcements

Lukas Renggli renggli at gmail.com
Tue Jan 3 08:20:55 EST 2012

>>> If everybody has its own version then we do not improve the infrastructure.
>> Performance issues aside, the current implementation forces me to use
>> a different implementation because Pharo's announcements have a
>> different implementation of selecting the handler (point 7). However,
>> the really weird thing is that Pharo's announcements are now suddenly
>> inconsistent with the Pharo exceptions and how they select the
>> handler. Do you think this is better or worse?
> you lost me here. why announcements have to be consistent with
> exceptions? something which is completely
> orthogonal to them?

Exceptions and Announcements used to implement a very similar
protocol: see their implementation of X class>>#handles:, X>>on:do:,
XSet>>#handles:, XSet>>#, etc.

Consistency makes frameworks easy to understand and use.

> it is like saying that apples are inconsistent with oranges.

- Apples and oranges are inconsistent the way they are eaten (oranges
have to be piled first and come in slices).

- Apples and pears are consistent the way they are eaten (even if they
taste very different).

If that is too abstract replace

  Apples => Announcements
  Oranges => change:/update:
  Pears => Exceptions


> aside of that, i added the changeset, so you can now choose whether
> your announcement subscription is handling
> announcement or not based on announcement object itself, not its class.
> see http://code.google.com/p/pharo/issues/detail?id=5145
> --
> Best regards,
> Igor Stasenko.

Lukas Renggli

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