Add custom operators (Part 1)

src/operators.lua

@@ -0,0 +1,66 @@
+local fmt = string.format
+local _loadfile = loadfile
+local var = "[%w%.%[%]_]"
+
+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,
+}
+
+local function compile(data)
+	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)
+	if line then
+		data = data:split"\n"
+		data[line] = data[line]:gsub("(" .. var .. "+)%s?=%s?(" .. var .. "*)", function(_,b) return b end)
+		data = table.concat(data, "\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)
+		end
+	end
+
+	return l, err
+end
+
+function loadfile(path)
+	return _load(path) or _loadfile(path)
+end