A concept for better hooks in Garry's Mod

gm_betterhooks.lua

local f = {} -- f is for hook functions.
local e = {} -- e is for broken hook functions.

local gmod = gmod
local pmv = SortedPairsByMemberValue

local unpack = unpack

local isstring = isstring
local isfunction = isfunction
local IsValid = IsValid

local lhook = hook
local hook = {}

_G.lhook = lhook
_G.hook = hook

function hook.GetTable()
	return f
end

function hook.GetErrors()
	return e
end

function hook.Add(event, id, callback, priority)
	if isstring(event) then
		event = {event}
	end
	for _,key in ipairs(event) do
		f[key] = f[key] or {}
		f[key][id] = {priority = priority, callback}
	end
end

function hook.Inject(event, func, after)
	local old = func

	if after then
		func = function(self, ...)
			local re = old(self, ...)
			hook.Run(event, re, ...)
			return re
		end
	else
		func = function(self, ...)
			hook.Run(event, ...)
			return old(self, ...)
		end
	end

	return func
end

function hook.Remove(event, id)
	if isstring(event) then
		event = {event}
	end
	for _,key in ipairs(event) do
		if f[event][id] then
			f[event][id] = nil
		end
	end
end

local function catch(event,id,info)
	local stack = debug.traceback(coroutine.running(), info, 2)
	local object = f[event] and f[event][id] or nil

	if object then
		object.errors = object.errors or {}
		table.insert(object.errors, stack)

		if #f[event][id].errors > 5 then
			e[event] = e[event] or {}
			e[event][id] = f[event][id]
			e[event][id].errors = stack

			f[event][id] = nil
		end
	end

	error(stack)
end

local function run(event, gm, ignore_priority, ...)
	local re

	if f[event] then
		if isstring(event) or IsValid(event) then
			if ignore_priority then
				for id, data in next, f[event] do
					re = {xpcall(data.callback, 
						function(info) catch(event,id,info) end, 
						...
					)}
					if re ~= nil then
						return unpack(re)
					end
				end
			else
				for id, data in pmv(f[event], 'priority') do
					re = {xpcall(data.callback, 
						function(info) catch(event,id,info) end, 
						...
					)}
					if re ~= nil then
						return unpack(re)
					end
				end
			end
		else
			f[event][id] = nil
		end
	end

	local GM = GM or GAMEMODE

	if GM then
		local GamemodeFunction = GM[event]
		if isfunction(GamemodeFunction) then
			return GamemodeFunction(GM, ...)
		end
	end
end

function hook.Call(event, gm, ...)
	local re = {run(event, gm, false, ...)}
	return unpack(re)
end

function hook.Run(event, ...)
	local re = {run(event, gmod and gmod.GetGamemode() or nil, false, ...)}
	return unpack(re)
end

function hook.RunEx(event, ignore_priority, delay, ...)
	local re
	local delay = CurTime() + delay

	if ( CurTime() > delay ) then
		re = {run(event, gmod and gmod.GetGamemode() or nil, ignore_priority, ...)}
		return unpack(re)
	end
end