make coords_from_string take more string formats

init.lua

@@ -188,16 +188,53 @@ local function coords_to_string(pos)
 end
 
 
+function trim(s)
+    -- code from lua-users.org
+    return s:match'^()%s*$' and '' or s:match'^%s*(.*%S)'
+end
+
+
+local function clamp(x, min, max)
+    return math.max(math.min(x, max), min)
+end
+
+
 local function coords_from_string(str)
-    -- numbers are separated by ","
+    -- parse "1,2,3" or "1 2 3" or "(1,2,3)" or "{x=1,y=2,z=3}" or return nil on fail
+    local function parse(str)
+	str = trim(str)
+	local result = nil
+	local first = string.sub(str, 1, 1)
+	local last = string.sub(str, -1, -1)
+	if first == "{" and last == "}" then
+	    local maybe_pos = minetest.deserialize("return " .. str)
+	    result = {x = maybe_pos.x, y = maybe_pos.y, z = maybe_pos.z}
+	end
+	
+	if not result and first == "(" and last == ")" then
+	    str = string.sub(str, 2, -2)
+	end
+	
+	if not result then
+	    -- numbers are separated by "," or " "
 	    local tmp = {}
 	    for n in string.gmatch(str, "([^, ]+)") do
 		table.insert(tmp, n)
 	    end
-    tmp[1] = tonumber(tmp[1]) or 0
-    tmp[2] = tonumber(tmp[2]) or 0
-    tmp[3] = tonumber(tmp[3]) or 0
-    return {x = tmp[1], y = tmp[2], z = tmp[3]}
+	    result = {x = tonumber(tmp[1]), y = tonumber(tmp[2]), z = tonumber(tmp[3])}
+	end
+	-- if any of xyz are not numbers, this will throw an error and pcall will fail
+	result.x = clamp(result.x, -32000, 32000)
+	result.y = clamp(result.y, -32000, 32000)
+	result.z = clamp(result.z, -32000, 32000)
+	return result
+    end
+    local success, result = pcall(parse, str)
+    if success then
+	return result
+    else
+	return nil
+    end
 end