+local ESCAPE_CHAR = string.char(0x1b)
+
+function core.get_color_escape_sequence(color)
+ return ESCAPE_CHAR .. "(c@" .. color .. ")"
+end
+
+function core.get_background_escape_sequence(color)
+ return ESCAPE_CHAR .. "(b@" .. color .. ")"
+end
+
+function core.colorize(color, message)
+ local lines = tostring(message):split("\n", true)
+ local color_code = core.get_color_escape_sequence(color)
+
+ for i, line in ipairs(lines) do
+ lines[i] = color_code .. line
+ end
+
+ return table.concat(lines, "\n") .. core.get_color_escape_sequence("#ffffff")
+end
+
+
+function core.strip_foreground_colors(str)
+ return (str:gsub(ESCAPE_CHAR .. "%(c@[^)]+%)", ""))
+end
+
+function core.strip_background_colors(str)
+ return (str:gsub(ESCAPE_CHAR .. "%(b@[^)]+%)", ""))
+end
+
+function core.strip_colors(str)
+ return (str:gsub(ESCAPE_CHAR .. "%([bc]@[^)]+%)", ""))
+end
+
+function core.translate(textdomain, str, ...)
+ local start_seq
+ if textdomain == "" then
+ start_seq = ESCAPE_CHAR .. "T"
+ else
+ start_seq = ESCAPE_CHAR .. "(T@" .. textdomain .. ")"
+ end
+ local arg = {n=select('#', ...), ...}
+ local end_seq = ESCAPE_CHAR .. "E"
+ local arg_index = 1
+ local translated = str:gsub("@(.)", function(matched)
+ local c = string.byte(matched)
+ if string.byte("1") <= c and c <= string.byte("9") then
+ local a = c - string.byte("0")
+ if a ~= arg_index then
+ error("Escape sequences in string given to core.translate " ..
+ "are not in the correct order: got @" .. matched ..
+ "but expected @" .. tostring(arg_index))
+ end
+ if a > arg.n then
+ error("Not enough arguments provided to core.translate")
+ end
+ arg_index = arg_index + 1
+ return ESCAPE_CHAR .. "F" .. arg[a] .. ESCAPE_CHAR .. "E"
+ elseif matched == "n" then
+ return "\n"
+ else
+ return matched
+ end
+ end)
+ if arg_index < arg.n + 1 then
+ error("Too many arguments provided to core.translate")
+ end
+ return start_seq .. translated .. end_seq
+end
+
+function core.get_translator(textdomain)
+ return function(str, ...) return core.translate(textdomain or "", str, ...) end
+end
+
+--------------------------------------------------------------------------------
+-- Returns the exact coordinate of a pointed surface
+--------------------------------------------------------------------------------
+function core.pointed_thing_to_face_pos(placer, pointed_thing)
+ -- Avoid crash in some situations when player is inside a node, causing
+ -- 'above' to equal 'under'.
+ if vector.equals(pointed_thing.above, pointed_thing.under) then
+ return pointed_thing.under
+ end
+
+ local eye_height = placer:get_properties().eye_height
+ local eye_offset_first = placer:get_eye_offset()
+ local node_pos = pointed_thing.under
+ local camera_pos = placer:get_pos()
+ local pos_off = vector.multiply(
+ vector.subtract(pointed_thing.above, node_pos), 0.5)
+ local look_dir = placer:get_look_dir()
+ local offset, nc
+ local oc = {}
+
+ for c, v in pairs(pos_off) do
+ if nc or v == 0 then
+ oc[#oc + 1] = c
+ else
+ offset = v
+ nc = c
+ end
+ end
+
+ local fine_pos = {[nc] = node_pos[nc] + offset}
+ camera_pos.y = camera_pos.y + eye_height + eye_offset_first.y / 10
+ local f = (node_pos[nc] + offset - camera_pos[nc]) / look_dir[nc]
+
+ for i = 1, #oc do
+ fine_pos[oc[i]] = camera_pos[oc[i]] + look_dir[oc[i]] * f
+ end
+ return fine_pos
+end
+
+function core.string_to_privs(str, delim)
+ assert(type(str) == "string")
+ delim = delim or ','
+ local privs = {}
+ for _, priv in pairs(string.split(str, delim)) do
+ privs[priv:trim()] = true
+ end
+ return privs
+end
+
+function core.privs_to_string(privs, delim)
+ assert(type(privs) == "table")
+ delim = delim or ','
+ local list = {}
+ for priv, bool in pairs(privs) do
+ if bool then
+ list[#list + 1] = priv
+ end
+ end
+ return table.concat(list, delim)
+end
+
+function core.is_nan(number)
+ return number ~= number
+end