Index of exceptions

C
Change_dialog [Wd_types]	The implementation of the `handle` method of a dialog may raise `Change_dialog` to drop the current dialog and continue with another dialog.
Change_page [Wd_types]	The implementation of the `handle` method of a dialog may raise `Change_page` to set the next page to display for the current dialog.
E
Element_exists [Wd_interactor]	Raised by some functions if there is already a component with the ID
F
Formal_user_error [Wd_types]	A formal error that happens independently of the current runtime state.
I
Instantiation_error [Wd_types]	An error generated by the `instantiate` method.
Invalid_session_checksum [Wd_dialog]	Raised when the session checksum as stored in the database is not the same that is transmitted by the browser.
N
No_such_variable [Wd_types]	It has been tried to access a non-declared variable.
R
Runtime_error [Wd_types]	A certain operation cannot be performed because the current state does not fulfill the necessary preconditions.
S
Session_not_found [Wd_dialog]	Raises when the current session was not found in the database.
T
Template_not_found [Wd_template]	Raised when a template cannot be found.