The "advice" feature lets you add to the existing definition of a function, by wrapping around the original function a "piece of advice".
Each piece of advice receives the original function and arguments; its result is returned to the caller as if from the original function.
A function may have multiple pieces of advice, which are composed by nesting earlier advice within later advice.
(Info-goto-node "(elisp)Advising Functions")
val around_values :
Symbol.t ->
Core_kernel.Source_code_position.t ->
?docstring:string ->
for_function:Symbol.t ->
?interactive:Defun.Interactive.t ->
((Ecaml_value.Value.t list -> Ecaml_value.Value.t) ->
Ecaml_value.Value.t list ->
Ecaml_value.Value.t) ->
unitaround_values ?docstring ?interactive here return_type advice_name f ~for_function defines function advice_name with body f and adds it as advice on for_function.
Compared to around_funcall, around_values provides looser coupling when the advice doesn't need to interact with the arguments or return value of for_function.
val around_funcall :
Symbol.t ->
Core_kernel.Source_code_position.t ->
?docstring:string ->
for_function:Symbol.t ->
?interactive:Defun.Interactive.t ->
'a Funcall.t ->
('a -> 'a) ->
unitaround_funcall provides typeful access to the arguments and return value of for_function.
(describe-function 'advice-add)