How to create new data types on Lua code?

Question

I've searched the web, but no tutorial really made it clear to me, so I need a brief explanation on this:

I want to create new data types for lua (in the C language compiler) for creating values like:

pos1 = Vector3.new(5, 5, 4) --Represents 3D position

pos2 = CFrame.new(4, 2, 1) * CFrame.Angles(math.rad(40), math.rad(20), math.rad(5)) --Represents 3D position AND rotation

These are some lines I could ordinary use on a game engine called Roblox. I want to recreate them for using outside Roblox.

There's no "brief" explanation for how to create objects. There are many ways of doing so in Lua, depending on how serious you are about it. — Nicol Bolas
– Nicol Bolas, Commented Mar 16, 2013 at 17:02
Why not using ordinary Lua tables (which are fully accessible from both C and Lua) for your new data types? — Egor Skriptunoff
– Egor Skriptunoff, Commented Mar 16, 2013 at 17:27

HennyH · Accepted Answer · 2013-05-07 04:49:50Z

1

local Vector3 = {} 
setmetatable(Vector3,{
    __index = Vector3;
    __add = function(a,b) return Vector3:new(a.x+b.x,a.y+b.y,a.z+b.z); end;
    __tostring = function(a) return "("..a.x..','..a.y..','..a.z..")" end
}); --this metatable defines the overloads for tables with this metatable
function Vector3:new(x,y,z) --Vector3 is implicitly assigned to a variable self
    return setmetatable({x=x or 0,y=y or 0,z=z or 0},getmetatable(self)); #create a new table and give it the metatable of Vector3
end 

Vec1 = Vector3:new(1,2,3)
Vec2 = Vector3:new(0,1,1)
print(Vec1+Vec2)

Outputs

(1,3,4)
>

answered May 7, 2013 at 4:49

HennyH

7,9842 gold badges33 silver badges40 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

HaveNoDisplayName · Accepted Answer · 2015-06-13 00:08:43Z

0

metatables and loadstring are the closes i have come to it in a similar way to this:

loadstring([=[function ]=] .. customtype .. [=[.new(...)
return loadstring( [[function() return setmetatable( {...} , {__index = function() return ]] .. ... .. [[ ) end )() end]] ]=] )()

This is just the gist of what i mean. Im sorry that its not neat and perfect, but at least its something to go on (i did not sleep much last night).

edited Jun 13, 2015 at 0:08

HaveNoDisplayName

8,537106 gold badges41 silver badges50 bronze badges

answered Jun 12, 2015 at 23:50

lolzeryest

662 bronze badges

Collectives™ on Stack Overflow

How to create new data types on Lua code?

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related