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@@ -3,6 +3,39 @@ Axxord
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Small blackboard system for Amber Smalltalk.
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+Axon
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+----
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+
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+Axon is a pub-sub system used in Axxord. It is fully generic, so it can be used
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+for other purposes as well, without using the rest of the library.
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+
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+It consists of two components: `Axon` abstract base class
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+(and its implemenetation `SimpleAxon`), which are subscription managers;
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+and `AxonInterest` abstract base class (and its pluggable implementation
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+`PluggableInterest`) that represent the actual subscription.
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+
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+You can create an axon, like in `axon := SimpleAxon new`. Then, you will add
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+some interests in an aspect, as in `axon addInterest: (PluggableInterest new
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+accept: [:aspect | aspect = #amount] enact: [Transcript show: 'Amount is ';
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+show: aThing amount; cr])`. It is not prescribed what an aspect can be,
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+or an aspect of what it is. It is used _only_ to distinguish whether the change
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+is related to the interest or not (as in previous example, one is interested
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+in changes of `#amount`).
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+
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+Whenever the change in some aspect happens for the object axon is watching,
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+axon should be let known, using `axon changed: #amount`. You can also
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+tell an axon that everything has changed, using `axon changedAll`.
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+Axon then makes related interests enact, eventually (it may or may not happen
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+immediately in the same thread, so enact should actually check if it is still
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+interesting when it takes its turn).
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+
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+There is no `removeInterest:`. The interest removes itself by signalling,
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+as in `PluggableInterest accept: [:aspect | aspect = #enabled]
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+enact: [aThing isEnabled ifTrue: [Transcript show: 'still alive'; cr]
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+ifFalse: [AxonOff signal]]`.
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+
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+Axon and friends are all in their dedicated `Axxord-Axon` category / package.
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+
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Axes
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----
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