Editing WoW:UI best practices (section)

=== Hook functions safely ===

See also: [[HOWTO: Hook functions in a safer way]]

You should do your best to write your addon in such a way that you don't need to hook functions. Even when it is necessary, most of the time [[API hooksecurefunc|hooksecurefunc]] is sufficient. However, there are occasional cases where "traditional" hooking must be used. When you do, remember to pass all parameters and return all results. Example:

 local OrigFunc = Func
 Func = function(foo, bar, ...)
     DoStuff()
     local blah, baz, rofl = OrigFunc(foo, bar, ...)
     DoOtherStuff()
     return blah, baz, rofl
 end

Even if the function only takes two parameters, you should always use the vararg (...). This will help future-proof your hook. If parameters are added to the function, your addon will safely ignore them while still passing them along.

There is actually a slight problem with the above example. If the number of return values from the function increases, your addon will likely cause erros. If you can call the original function as your last step, this is easy to deal with:

 return OrigFunc(foo, bar, ...)

If you need to do processing based on the return value, you'll need to create a table to store the results of the call:

 local ret = {OrigFunc(foo, bar, ...)}
 DoStuff()
 return unpack(ret)