Improve preprocessor a bit

src/preprocessor.lua

@@ -0,0 +1,90 @@
+--[[    All source files have to be preprocessed before loading.
+	This allows implementing custom operators like bitwise ones.	]]
+
+local fmt, split = string.format, string.split
+local var = "[%w%.%[%]\"\'_]"
+local modpath = core.get_modpath"i3"
+local _,_, fs_elements = dofile(modpath .. "/src/styles.lua")
+
+local operators = {
+	["([%+%-%*%^/&|])="] = function(a, b, c)
+		return fmt("%s = %s %s %s", a, a, b, c)
+	end,
+
+	["+%+"] = function(a, b)
+		return fmt("%s = %s + 1\n%s", a, a, b)
+	end,
+
+	["&"] = function(a, b)
+		return fmt("bit.band(%s, %s)", a, b)
+	end,
+
+	["|"] = function(a, b)
+		return fmt("bit.bor(%s, %s)", a, b)
+	end,
+
+	["<<"] = function(a, b)
+		return fmt("bit.lshift(%s, %s)", a, b)
+	end,
+
+	[">>"] = function(a, b)
+		return fmt("bit.rshift(%s, %s)", a, b)
+	end,
+
+	["<<="] = function(a, b)
+		return fmt("%s = bit.lshift(%s, %s)", a, a, b)
+	end,
+
+	[">>="] = function(a, b)
+		return fmt("%s = bit.rshift(%s, %s)", a, a, b)
+	end,
+}
+
+local function compile(data)
+	data = data:gsub("IMPORT%((.-)%)", function(a)
+		return "local " .. a:gsub("\"", "") .. " = i3.get(" .. a .. ")"
+	end)
+
+	data = data:gsub("([%w_]+)%(", function(a)
+		if fs_elements[a] then
+			return fmt("fs('%s',", a)
+		end
+	end)
+
+	for op, func in pairs(operators) do
+		data = data:gsub("(" .. var .. "+)%s?" .. op .. "%s?(" .. var .. "*)", func)
+	end
+
+	return data
+end
+
+local function _load(path, line, data, t)
+	if line then
+		if not t then
+			t = split(data, "\n")
+		end
+		t[line] = t[line]:gsub("(" .. var .. "+)%s?=%s?(" .. var .. "*)", "%2")
+		data = table.concat(t, "\n")
+	else
+		local file = assert(io.open(path, "r"))
+		data = file:read"*a"
+		file:close()
+		data = compile(data)
+	end
+
+	local l, err = loadstring(data)
+
+	if not l then
+		local err_line = tonumber(err:match(":(%d+):"))
+
+		if line ~= err_line then
+			return _load(path, err_line, data, t)
+		end
+	end
+
+	return l, err
+end
+
+return function(path)
+	return _load(path) or loadfile(path)
+end