IceGT_'s Hook System and Table extensions

[IceGT_]

Hi, this would be my first post. What I have to offer is...

Hooks - https://github.com/icegt95/icegts_love2 ... e_hook.lua
...another hook system that I'm currently using in a project I hope to get greenlit this year, which is kinda like the one GMod uses, but kinda not - the main difference being that hook.call will return a table of all values returned by any called hook. hook.run will return the first value it receives. The system can be modified easily to perform differently if need be.

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--	Example 1:

		hook.add( "ShouldSkipStartupMessage", "blocking_1", function()
			
			return true
			
		end )

		love.load = function()

			local should_skip = hook.run( "ShouldSkipStartupMessage" )
			if not ( should_skip == true ) then -- for demonstration purposes
				print( "Startup message wasn't skipped" )
			end

		end



--	Example 2:

		hook.add( "LoveGameStartOrSomething", "ex2_hooka", function( num1, num2, num3 )
			
			return "Random numbers to format for results_tab - " .. num1 .. ", " .. num2 .. ", " .. num3 .. "!"
			
		end )

		hook.add( "LoveGameStartOrSomething", "ex2_hookb", function( num1, num2, num3 )
			
			return "This will also be returned in results_tab - " .. num1 .. ", " .. num2 .. ", " .. num3 .. "!"
			
		end )

		love.load = function()

			local results_tab = hook.call( "LoveGameStartOrSomething", math.random(), math.random(), math.random() )
			
			if results_tab then

				for idx, res_str in next, results_tab, nil do

					print( res_str )

				end

			end

		end

Table library extension - https://github.com/icegt95/icegts_love2 ... _table.lua
Expands on lua's table library with functions similar to those in Garry's Mod.

[Sir_Silver]

Well that is an interesting coincidence that another new user just yesterday shared their reinterpretation of gmod's hook library here: viewtopic.php?f=5&t=83345

I remember also making my own version of the hook library in the past. =)

[IceGT_]

Just added tables, but it's getting a bit too late for me to implement sorting stuff tonight, so that bit should be out tomorrow if all goes well.

[Sir_Silver]

Interesting, pretty soon looks like there's gonna be a working version of gmod in love lol.

I was looking at your library there and I noticed a couple of problems - I've made these same mistakes myself.

The function below that you've written will stack overflow if the index metamethod of a table points to itself (you may or may not consider this an issue depending on whether or not you use the metamethods).

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table.copy = function( t )
	
assert( type( t ) == "table", "Passed argument is not a table." )
	
local tab = {}
	
for k,v in next, t, nil do
		
	tab[k] = ( type( v ) == "table" ) and table.copy( v ) or v
	
end
	
return tab

local metatable = {}
metatable.__index = metatable

table.copy(metatable)
-> [string "table.copy = function( t )..."]:3: stack overflow
end

This one just won't work for a very simple reason, your not overwriting the table that you think you are passing, you are overwriting the reference to the table your passing. That's something that took me a while to understand (not saying you don't understand this, could have just been overlooked).

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table.empty = function( t )

	assert( type( t ) == "table", "Passed argument is not a table." )
	
	t = {}

end

local tab = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}

table.empty(tab)

for k, v in pairs(tab) do
	print(k, v)
end

->
1	1		
2	2		
3	3		
4	4		
5	5		
6	6		
7	7		
8	8		
9	9		
10	10	

Hope I didn't sound too mean, just trying to help out a fellow programmer

[IceGT_]

Thanks for pointing that out, the issue with table.empty was def an overlook on my part - table.copy was just me forgetting that circular references exist (whoops). I've pushed the following fixes, though I want your opinion on how the table.copy fix handles stuff, if you don't mind. This is adapted straight from http://lua-users.org/wiki/PitLibTablestuff, which is apparently where Garry ripped his version from.

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table.empty = function( t )

	assert( type( t ) == "table", "Passed argument is not a table." )
	
	for k,_ in next, t, nil do
		
		t[k] = nil
	
	end

end

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table.copy = function( t, st )

	assert( type( t ) == "table", "Passed argument is not a table." )
	
	local tab = {}
	
	for k,v in next, t, nil do
		
		if type( v ) == "table" then
			
			local st = st or {}
			st[t] = tab
			
			tab[k] = ( not ( st[v] == nil ) ) and v or table.copy( v )
		
		else
		
			tab[k] = v
		
		end
	
	end
	
	return tab

end

Output:


Test code:

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local mt = { ["test"] = "4" }
mt.__index = mt

local x = table.copy( mt )

print( "mt __index:" )
print( mt.__index )
print( "x __index:" )
print( x.__index )

print( "mt.test: " .. mt["test"] )
print( "x.test: " .. x["test"] )

x["test"] = "5"

print( "x.test = 5" )
print( "mt.test: " .. mt["test"] )
print( "x.test: " .. x["test"] )

mt.other = "6"

print( "mt.other = 6" )
print( "mt.other: " .. mt["other"] )
print( "x.other: " .. ( x["other"] or "<not set>" ) )