Module lib.container.observable
Create an Observable value (object).
An observable value notifies registered observers each time the value is set.
Functions
| Observable:set (value, quiet) | Set the value |
| Observable:__call () | Return the current value (short hand for the 'value' method) |
| Observable:value () | Return the current value |
| Observable:register (observer, handler) | Register an observer of value changes
An observer is identified by a key which can be any type (number, string, table, etc). |
| Observable:unregister (observer) | Unregister an observer of value changes |
| Observable:notify_observers () | Notify registered observers of current value (normally called by `set`). |
Functions
- Observable:set (value, quiet)
-
Set the value
Parameters:
- value anything New value for observable.
- quiet boolean If true, do not notify observers.
- Observable:__call ()
-
Return the current value (short hand for the 'value' method)
Returns:
-
anything
- Observable:value ()
-
Return the current value
Returns:
-
anything
- Observable:register (observer, handler)
-
Register an observer of value changes
An observer is identified by a key which can be any type (number, string, table, etc). Registering an observer replaces any previous registration associated with that key.
The handler is a function which is passed one argument, the new value. If `handler` is not provided it is assumed that the `observer` is an object with a `notify` method and the `notify` method is called with the new value.
Parameters:
- observer anything Identity of observer.
- handler function New value callback, optional.
- Observable:unregister (observer)
-
Unregister an observer of value changes
Parameters:
- observer anything Identity of observer.
Returns:
-
boolean
true if the observer was known and unregistered.
- Observable:notify_observers ()
- Notify registered observers of current value (normally called by `set`).