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2.4.3 Configuration events

When the value of a configuration parameter is altered, either directly or by loading a configuration file, a configuration event is generated. Handlers can be registered to be notified when a configuration event occurs. A configuration event is associated with the group and key that had its value modified.

If a configuration event is emitted by a configuration context, it propagates to all configuration contexts which inherit that group and key from it.

A configuration event handler must be a closure that accepts three arguments:

     handler cfg group key

cfg is always the configuration context that received the event, and the group and key identify the configuration parameter that changed.

— Function: add-config-event! cfg handler

Registers handler to be called when configuration changes in the context cfg.

— Function: remove-config-event! cfg handler

Stops handler from being called when configuration changes in the context cfg.