Module:core.events

Infrastructure for registering and firing callbacks on application events.

UnlikeIPython.core.hooks, which lets end users set single functions tobe called at specific times, or a collection of alternative methods to try,callbacks are designed to be used by extension authors. A number of callbackscan be registered for the same event without needing to be aware of one another.

The functions defined in this module are no-ops indicating the names of availableevents and the arguments which will be passed to them.

Note

This API is experimental in IPython 2.0, and may be revised in future versions.

1 Class

classIPython.core.events.EventManager(shell:InteractiveShell,available_events:Iterable[str],print_on_error:bool=True)

Bases:object

Manage a collection of events and a sequence of callbacks for each.

This is attached toInteractiveShellinstances as anevents attribute.

Note

This API is experimental in IPython 2.0, and may be revised in future versions.

__init__(shell:InteractiveShell,available_events:Iterable[str],print_on_error:bool=True)→None

Initialise theCallbackManager.

Parameters:

  • shell – TheInteractiveShell instance

  • available_events – An iterable of names for callback events.

  • print_on_error – A boolean flag to set whether the EventManager will print a warning which a event errors.

register(event:str,function:Callable[[...],Any])→None

Register a new event callback.

Parameters:

  • event (str) – The event for which to register this callback.

  • function (callable) – A function to be called on the given event. It should take the sameparameters as the appropriate callback prototype.

Raises:

  • TypeError – Iffunction is not callable.

  • KeyError – Ifevent is not one of the known events.

trigger(event:str,*args:Any,**kwargs:Any)→None

Call callbacks forevent.

Any additional arguments are passed to all callbacks registered for thisevent. Exceptions raised by callbacks are caught, and a message printed.

unregister(event:str,function:Callable[[...],Any])→None

Remove a callback from the given event.

5 Functions

IPython.core.events.pre_execute()→None

Fires before code is executed in response to user/frontend action.

This includes comm and widget messages and silent execution, as well as usercode cells.

IPython.core.events.pre_run_cell(info:Any)→None

Fires before user-entered code runs.

Parameters:

info (ExecutionInfo) – An object containing information used for the code execution.

IPython.core.events.post_execute()→None

Fires after code is executed in response to user/frontend action.

This includes comm and widget messages and silent execution, as well as usercode cells.

IPython.core.events.post_run_cell(result:Any)→None

Fires after user-entered code runs.

Parameters:

result (ExecutionResult) – The object which will be returned as the execution result.

IPython.core.events.shell_initialized(ip:InteractiveShell)→None

Fires after initialisation ofInteractiveShell.

This is before extensions and startup scripts are loaded, so it can only beset by subclassing.

Parameters:

ip (InteractiveShell) – The newly initialised shell.