Unable to set new global environments

Solar2D General Questions/Discussion
#1

In lua engines like pico8 you can swap between the global environment and any user defined ones. A basic setup in pico8 is:

_G = _ENV; _G.__index = _G --header

player={x=30};setmetatable(player,_G)
do
	local _ENV=player
	function update()
		x+=1
	end
	function draw()
		circ(x,63,8)
	end
end

function _update() player:update() end
function _draw()cls(1) player:draw() end --displays circle moving right

I’m not having any luck translating this into solar2d. It’s not accepting the header line: _G = _ENV; _G.__index = _G
In solar2d it seems _G exists as the default environment name.
Whereas pico8 it’s _ENV. Swapping the names in the code above will move it past the header but the read of the code won’t work, it’ll recognize x as a nonexistant global.

#2

It is not a common practice to reference the environments in Solar2D.

I’m not sure what you are exactly trying to achieve, but I think that what you are looking for is getfenv() and setfenv(), try:

_G = getfenv(); _G.__index = _G --header

Pico8 uses its own lua version, while Solar2D uses Lua 5.1, so you can look at any docs referencing the standard Lua 5.1 and it should work in Solar2D.

#3

The outstanding problem is this line local _ENV=player. In the OP for pico8 it is the necessary component to getting most of this to work.

The usage+examples for pico8 are well out-lined here: Using _𝘦𝘯𝘷 in PICO-8
This is the core example I need to get working. Examples like below are not valid in solar2d even if I change env to _G:

player={}

do
  local _𝘦𝘯𝘷=player
  x=10
  y=20
  lives=3
  sp=1
end --player={x=10,y=20...,sp=1}

The best I could get was the below two in solar2d. The second is the best but it will not allow me to store anything in obj like obj={x=xx,y=yy} and then call them like x , y Because that local _ENV=obj line doesn’t work…that’s the line that lets u do it in pico8.

--ENV EXAMPLE #1
CAT={__index = _G}
player={x=30,y=40}; setmetatable(player,CAT)
-- local x=1000 --main worry is this...if we have the same variable name as a local with overlappipng scope
function update()
	x=x+100
end; setfenv(update,player)
player.update() print(player.x) --130


--ENV EXAMPLE #2
CAT={__index = _G}
local h=100
local bullets={}
local function make_bullet(xx,yy) --parameters must be unique
	local obj={}; setmetatable(obj,CAT)
--local _ENV=obj --the line that doesn't work but would allow u in pico8 to write obj={x=xx} above
	x=xx or -1 y=yy or -2 r=3 --init var must not overlap with scope of a local var of same name
	function update()
		x=x+ h
	end
	table.insert(bullets,obj)
end
make_bullet(1,2) bullets[1].update() print(bullets[1].x) --1+100=101
#4

The local _ENV=obj line in example#2 above can be substituted with setfenv(make_bullet,obj), so that can work similar to pico8 now in that format. The problem is setfenv only applies to functions, so I’m still stuck.

--ENV EXAMPLE #2
CAT={__index = _G}
local h=100
local bullets={}
local function make_bullet(xx,yy) --parameters must be unique
	local obj={x=xx,dmg=5}; setmetatable(obj,CAT); setfenv(make_bullet,obj)
	hp=900
	function update() x=x+ 1 end
	table.insert(bullets,obj)
end
make_bullet(-10,2)

--local tik=0; Runtime:addEventListener("enterFrame", function(event) tik=event.frame
	for i=1,#bullets do
		bullets[i].update()
		print(bullets[i].x) --x=-10; x = -10+1 = -9
		print(bullets[i].dmg) --5
		print(bullets[i].hp) --900
	end
-- end)