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I define support for hookable instance methods.
These are methods which you can register pre-call and post-call external functions to augment their functionality. People familiar with more esoteric languages may think of these as "method combinations".
This could be used to add optional preconditions, user-extensible callbacks (a-la emacs) or a thread-safety mechanism.The four exported calls are:
All have the signature (class, methodName, callable), and the callable they take must always have the signature (instance, *args, **kw) unless the particular signature of the method they hook is known.Hooks should typically not throw exceptions, however, no effort will be made by this module to prevent them from doing so. Pre-hooks will always be called, but post-hooks will only be called if the pre-hooks do not raise any exceptions (they will still be called if the main method raises an exception). The return values and exception status of the main method will be propogated (assuming none of the hooks raise an exception). Hooks will be executed in the order in which they are added.
|Class||HookError||An error which will fire when an invariant is violated.|
|Function||addPre||hook.addPre(klass, name, func) -> None|
|Function||addPost||hook.addPost(klass, name, func) -> None|
|Function||removePre||hook.removePre(klass, name, func) -> None|
|Function||removePost||hook.removePre(klass, name, func) -> None|
|Function||PRE||(private) munging to turn a method name into a pre-hook-method-name|
|Function||POST||(private) munging to turn a method name into a post-hook-method-name|
|Function||ORIG||(private) munging to turn a method name into an `original' identifier|
|Function||_XXX||string manipulation garbage|
|Function||_addHook||(private) adds a hook to a method on a class|
|Function||_removeHook||(private) removes a hook from a method on a class|
|Function||_enhook||(private) causes a certain method name to be hooked on a class|
|Function||_dehook||(private) causes a certain method name no longer to be hooked on a class|
hook.addPre(klass, name, func) -> NoneAdd a function to be called before the method klass.name is invoked.
hook.addPost(klass, name, func) -> NoneAdd a function to be called after the method klass.name is invoked.
hook.removePre(klass, name, func) -> NoneRemove a function (previously registered with addPre) so that it is no longer executed before klass.name.
hook.removePre(klass, name, func) -> NoneRemove a function (previously registered with addPost) so that it is no longer executed after klass.name.