Just a shorthand I found that can save you some keystrokes if you use string functions a lot, especially string.format. Instead of “string.format(“%s %d:%02d”, var_a, var_b, var_c)” for example, you can say:
(“%s %d:%02d”):format(var_a, var_b, var_c)
Note the syntax: the format string in quotes inside parens, then a colon, then “format”, and the parameters in parens. I don't actually know why the parens around the format string are necessary; I would not think they would be. I'm sure they aren't needed if the format is not a literal string (e.g. it's a variable).