implement __pairs for entity, entity_components, etc

[GinjaNinja32]

most of the implementations are just "make a table with all the values and delegate to next", with the exception of entity which is "return the components key then delegate to next with the LTC table".

if the C++ had a deterministically-ordered list of the keys, the functions could be smarter, but this works and the tables should be sufficiently temporary for it to not matter.

[GinjaNinja32]

with this PR:

-- basic table dump function
function dump(t, level)
	if type(t) ~= "table" and type(t) ~= "userdata" then
		return tostring(t)
	end

	level = level or 0

	local entries = {}
	for k, v in pairs(t) do
		table.insert(entries, dump(k, level+1) .. "=" .. dump(v, level+1))
	end

	local pfx = ""
	if type(t) == "userdata" then
		pfx = tostring(t):gsub(":.*", "")
	end

	local indent = ("\t"):rep(level)
	return pfx .. "{\n\t" .. indent .. table.concat(entries, ",\n\t" .. indent) .. "\n" .. indent .. "}"
end

function init()
	entity = createEntity()

	entity.foo = 42
	entity.bar = {x=1, y=2, z=3}

	entity.components.callsign = { callsign = "Test Entity" }
	entity.components.hull = {
		current = 200,
		max = 250,
		allow_destruction = false,
	}
	entity.components.shields = {
		{ max = 100, level = 100 },
		{ max = 100, level = 99 },
		{ max = 100, level = 98 },
		{ max = 100, level = 97 },
	}

	print(dump(entity))
end

prints:

entity{
	components=entity_components{
		hull=hull{
			damaged_by_energy=true,
			max=250.0,
			damaged_by_emp=false,
			allow_destruction=false,
			current=200.0,
			damaged_by_kinetic=true
		},
		callsign=callsign{
			callsign=Test Entity
		},
		shields=shields{
			1=shields_array{
				max=100.0,
				length=4,
				level=100.0
			},
			2=shields_array{
				max=100.0,
				length=4,
				level=99.0
			},
			3=shields_array{
				max=100.0,
				length=4,
				level=98.0
			},
			4=shields_array{
				max=100.0,
				length=4,
				level=97.0
			},
			front_can_be_hacked=true,
			active=true,
			front_heat_add_rate_per_second=0.050000000745058,
                        [... the rest of the shields component fields]
			rear_coolant_level=0.0
		}
	},
	foo=42,
	bar={
		z=3,
		y=2,
		x=1
	}
}

[daid]

Masterful! I need to give it a proper review, but this was on my wishlist!