Merge pull request 'tools: set up luacheck' (#57) from e/Mineclonia:luacheck-setup into master

Reviewed-on: https://git.minetest.land/Mineclonia/Mineclonia/pulls/57
Reviewed-by: Elias Åström <ryvnf@riseup.net>

.luacheckrc

@@ -0,0 +1,102 @@
+std = "min"
+
+read_globals = {
+	"ItemStack",
+	"dump", "dump2",
+	"vector",
+	"VoxelArea",
+	"minetest",
+	"PseudoRandom",
+	"PerlinNoise",
+	"PcgRandom",
+
+	string = {fields = {"split", "trim"}},
+	table  = {fields = {"copy", "getn", "indexof", "insert_all"}},
+	math   = {fields = {"hypot", "round"}},
+}
+
+-- A config option to allow r/w access to mods which contain
+-- this one. It only avoids a couple warnings, and may not be
+-- the behavior we want, so it's disabled by default.
+local allow_parents=false
+
+local lfs = require "lfs"
+
+-- Seed the queue with the mods/ directory
+local queue={ {"mods"} }
+
+local function check(dir)
+	-- Get the string of the directory path
+	local sdir=table.concat(dir, "/")
+	-- Save the top-level directory name as a
+	-- fallback in case there's no mod.conf,
+	-- or no name= directive.
+	local name=dir[#dir]
+
+	-- Is there a mod.conf?
+	if lfs.attributes(sdir.."/mod.conf", "mode") == "file" then
+		local deps={}
+		for line in io.lines(sdir.."/mod.conf") do
+			-- Use name= if it's there
+			name=string.match(line, "name *= *([a-zA-Z0-9_]+)") or name
+			-- Get the dependency entries (if they're there)
+			local ents=string.match(line, "depends *=(.*)$")
+			if ents then
+				-- Split them in to the comma-separated names
+				for m in string.gmatch(ents, "([a-zA-Z0-9_]+),?") do
+					table.insert(deps, m)
+				end
+			end
+		end
+
+		local glb={ name }
+		if allow_parents then
+			for _, v in pairs(dir) do
+				-- Skip ALL-CAPS names since those tend
+				-- to be collections of mods instead of
+				-- mods themselves.
+				if not string.match(v, "^[A-Z]+$") then
+					table.insert(glb, v)
+				end
+			end
+		end
+
+		-- Tell Luacheck what the directory is allowed to do
+		files[sdir]={
+			globals = glb,
+			read_globals = deps,
+		}
+	elseif lfs.attributes(sdir.."/init.lua", "mode") == "file" then
+		-- No mod.conf, but there's an init.lua here.
+		local glb={ name }
+		if allow_parents then
+			for _, v in pairs(dir) do
+				-- Again, skip ALL-CAPS.
+				if not string.match(v, "^[A-Z]+$") then
+					table.insert(glb, v)
+				end
+			end
+		end
+
+		files[sdir]={ globals=glb }
+	end
+
+	-- Queue any child directories
+	for d in lfs.dir(sdir) do
+		-- Skip hidden directories and parent/current directories.
+		if lfs.attributes(sdir.."/"..d, "mode") == "directory" and not string.match(d, "^%.") then
+			-- Copy dir in to nd (New Dir)
+			local nd={}
+			for k, v in pairs(dir) do
+				nd[k]=v
+			end
+			nd[#nd+1]=d
+			table.insert(queue, nd)
+		end
+	end
+end
+
+while #queue > 0 do
+	-- Pop an entry and process it.
+	check(table.remove(queue, 1))
+end