HasCallbackProperties

class echo.HasCallbackProperties

Bases: object

A class that adds functionality to subclasses that use callback properties.

Methods

add_callback(name, callback[, echo_old, ...])	Add a callback that gets triggered when a callback property of the class changes.
add_global_callback(callback)	Add a global callback function, which is a callback that gets triggered when any callback properties on the class change.
callback_properties()	Return a list of all callback property names.
clear_callbacks()	Remove all global and property-specific callbacks.
is_alias(name)	Whether a property (identified by name) is a callback property alias.
is_callback_property(name)	Whether a property (identified by name) is a callback property.
iter_callback_properties()	Iterator to loop over all callback properties.
remove_callback(name, callback)	Remove a previously-added callback
remove_global_callback(callback)	Remove a global callback function.

Methods Summary

add_callback(name, callback[, echo_old, ...])	Add a callback that gets triggered when a callback property of the class changes.
add_global_callback(callback)	Add a global callback function, which is a callback that gets triggered when any callback properties on the class change.
callback_properties()	Return a list of all callback property names.
clear_callbacks()	Remove all global and property-specific callbacks.
is_alias(name)	Whether a property (identified by name) is a callback property alias.
is_callback_property(name)	Whether a property (identified by name) is a callback property.
iter_callback_properties()	Iterator to loop over all callback properties.
remove_callback(name, callback)	Remove a previously-added callback
remove_global_callback(callback)	Remove a global callback function.

Methods Documentation

add_callback(name, callback, echo_old=False, priority=0, validator=False)

Add a callback that gets triggered when a callback property of the class changes.

Parameters:

namestr

The instance to add the callback to.

callbackfunc

The callback function to add

echo_oldbool, optional

If True, the callback function will be invoked with both the old and new values of the property, as callback(old, new). If False (the default), will be invoked as callback(new)

priorityint, optional

This can optionally be used to force a certain order of execution of callbacks (larger values indicate a higher priority).

validatorbool, optional

Whether the callback is a validator, which is a special kind of callback that gets called before the property is set. The validator can return a modified value (for example it can be used to change the types of values or change properties in-place) or it can also raise an exception.

add_global_callback(callback)

Add a global callback function, which is a callback that gets triggered when any callback properties on the class change.

Parameters:

callbackfunc

The callback function to add

callback_properties()

Return a list of all callback property names.

Note: This does not include CallbackPropertyAlias instances, only actual CallbackProperty instances.

clear_callbacks()

Remove all global and property-specific callbacks.

is_alias(name)

Whether a property (identified by name) is a callback property alias.

Parameters:

namestr

The name of the property to check

is_callback_property(name)

Whether a property (identified by name) is a callback property.

Returns True for both CallbackProperty and CallbackPropertyAlias.

Parameters:

namestr

The name of the property to check

iter_callback_properties()

Iterator to loop over all callback properties.

Note: This does not include CallbackPropertyAlias instances, only actual CallbackProperty instances.

remove_callback(name, callback)

Remove a previously-added callback

Parameters:

namestr

The instance to remove the callback from.

funcfunc

The callback function to remove

remove_global_callback(callback)

Remove a global callback function.

Parameters:

callbackfunc

The callback function to remove