Infering names of fields of inside a table, inside a class

[Mugworth]

Ok it's just easier to show, i have no idea what i should write in title:

Here is Animation file

---@class Animation.Simple.package
---@field addGrid Animation.Simple
---@field build Animation.Simple.Builder

---@class Animation.Simple
---@overload fun(O:animationOpts?): Animation.Simple
---@field image love.Image
---@field width number width of frame
---@field height number height of frame
---@field duration table|number duration of frame
---@field state string animation state type
---@field private __grid? table
---@field private newGrid function
---@field type table type of animation
local Animation = class("Animation.Simple")

function Animation:initialize(O)
...
end

--- Create animation grid
---@class animationOpts
---@field image love.Image
---@field width number width of frames
---@field height number height of frames
---@field state? string animation state type
---@field top? number origin coordinate top
---@field left? number origin coordinate left
---@field border? number
---@field duration number

---Create new grid
---@param O animationOpts
---@return self
function Animation:newGrid(O)
...
end

--- Add animation based on frames and grid
---@param name string of animation
---@param frames table string of frames
---@param duration? table | number duration of frame
---@param onLoop? function fn called every loop
---@return self
function Animation:add(name, frames, duration, onLoop)
...
end


---@class AnimationTable
---@field [string] Animation.Simple

---@class Animation.Simple.Builder
---@overload fun(O: fun(): {[string]: Animation.Simple}): Animation.Simple.Builder
---@field private __current string
---@field types AnimationTable
local AnimationBuilder = class("Animation.Builder")
function AnimationBuilder:initialize(fun)

end

--- Set default animation
---@param str string animation name
---@return self
function AnimationBuilder:grid(str)
...
end

---get current Animation
---@return Animation.Simple
function AnimationBuilder:current()
...
end


return {
	addGrid = Animation,
	build = AnimationBuilder,
}

and here how i use it

self.animation = Animation.build(function()
	local image = love.graphics.newImage("assets/RPGW/Zombie.png")

	return {
		default = Animation.addGrid({
			image = image,
			height = 32,
			width = 32,
			duration = 0.2,
		})
			:add("idle", { "1-8", 1 })
			:add("running", { "1-8", 3 })
			:add("attack", { "1-7", 2 })
			:add("dying", { "1-9", 6 }, nil, function(s)
				s:pauseAtEnd()
			end)
			:action("idle"),
			
		second = Animation.addGrid({
			image = image,
			height = 32,
			width = 32,
			duration = 0.2,
		})
			:add("idle", { "1-8", 1 })
			:add("running", { "1-8", 3 })
			:add("attack", { "1-7", 2 })
			:add("dying", { "1-9", 6 }, nil, function(s)
				s:pauseAtEnd()
			end)
			:action("idle"),
	}
end):grid("default")

i would like to know if there exist a way for luals to infer names of default and second, they are fields that will exist in self.animation.types table

[Mugworth]

One of the things i thought about and do it like so:

---@class Animation.Simple.Zombie: Animation.Simple.Builder
---@field types.default Animation.Simple
---@field types.second Animation.Simple
self.animation = Animation.build(function()
...

but is there an option for luals automatically infer such fields?

[tomlau10]

IIUC, you want self.animation.types to suggest default / second as its fields?
In other words, you want the return table type of the callback from Animation.build(), to be the type of self.animation.types?

firstly your syntax is incorrect

The syntax @field types.default ... in your original comment is incorrect.
You cannot define nested sub fields in this way.
The closest thing is using table literal:

---@field types { default: Animation.Simple, second: Animation.Simple }

-- or in multi-lined format

---@field types {
--- default: Animation.Simple,
--- second: Animation.Simple,
---}

but of course this still doesn't fulfil your request that automatically suggest default/second fields without manually annotation.

suggestion: using a class AnimationTable.Zombie

In this case, I think you may try something like this:

• creating a class AnimationTable.Zombie for that return table
• luals will auto inject the literal table defined fields into this new class
• then make self.animation as a class having the field types: AnimationTable.Zombie

function Zombie:init()
    ---@class Animation.Simple.Zombie: Animation.Simple.Builder
    ---@field types AnimationTable.Zombie
    self.animation = Animation.build(function()
        local image = love.graphics.newImage("assets/RPGW/Zombie.png")

        ---@class AnimationTable.Zombie
        local zombieAnimations = {
            default = Animation.addGrid({
...
        }
        return zombieAnimations
    end):grid("default")
end

but you have to fix an annotation warning first

You need to deal with the Undefined field `action`. warning.
I don't know if it is already annotated in your original code or not, but it's not in your example. 😕
You have to at least add the following in your Animation.lua file

---@return self
function Animation:action(name)
end

=> such that the chain call :action() can still return Animation.Simple
=> then both default and second in zombieAnimations can be inferred as Animation.Simple correctly

result

Now self.animation.types.<autocomplete> => will suggest default / second
And if you want other keys to be inferred as Animation.Simple as well, you can let AnimationTable.Zombie to inherit AnimationTable:

---@class AnimationTable.Zombie: AnimationTable
local zombieAnimations = {
...