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POExtend gen_event behavior in Erlang
 

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  1. POExtend gen_event behavior in Erlang
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    <p>I'm writing an event manager that will take a lot of different event handlers. This event manager will be notified with a lot of different events. Each handler only handle certain events, and ignore the rest. Each handler can also trigger certain other events based on situation.</p> <p>For example, first handler to handle <code>Event1</code></p> <pre class="lang-erl prettyprint-override"><code>-module (first_handler). -behavior (gen_event). ... handle_event(Event1, State) -&gt; {ok, State}; handle_event(_, State) -&gt; {ok, State}. </code></pre> <p>Second handler to handle <code>Event2</code></p> <pre class="lang-erl prettyprint-override"><code>-module (second_handler). -behavior (gen_event). ... handle_event(Event2, State) -&gt; gen_event:notify(self(), Event1), {ok, State}; handle_event(_, State) -&gt; {ok, State}. </code></pre> <p>The event triggering can be done by calling <code>gen_event:notify(self(), NewEvent)</code> within a <code>handle_event</code> of the handler, but I would rather abstract and export that out so that it can be called from the event manager.</p> <p>Since pattern matching and ignoring events and triggering events are common to all the handlers, is there anyway I can extend <code>gen_event</code> behavior to provide those as built-ins?</p> <p>I'll start with the default way to create a custom behavior:</p> <pre class="lang-erl prettyprint-override"><code>-module (gen_new_event). -behaviour (gen_event). behaviour_info(Type) -&gt; gen_event:behaviour_info(Type). </code></pre> <p>I'm not sure what to do next.</p>
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