'''`[Tcllib%|%hook]`''' is a [Tcllib] package tht implements the subject/observer ([Tcl implementations of publish-subscribe mechanisms%|%publish/subscribe]) pattern.



** What the Critics Say **

   ''[hook] has become an essential part of my toolbox. I can't imagine developing a medium size app without having such functionality'':   [eg%|%Emiliano Gavilán], [Tcl Chatroom], 2022-04-08



** Description **

`hook` allows subjects, which may be modules, objects, widgets, and so forth, to synchronously call hooks which may be bound to an arbitrary number of subscribers, called observers.  A subject may call any number of distinct hooks, and any number of observers can bind callbacks to a particular hook called by a particular subject.  Hook bindings can be queried and deleted.

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