unescape lua string (opposite of %q)

[Graham Wakefield <wakefield@...>]

Hmm, I must be slow. I can't figure out how to convert a string with represented control characters into a string with actual control characters.

E.g.:

local input = [[ line 1\nline2 ]]

Into a string which will print like this:

line1
line2



For individual characters, this works:

str:gsub("\\n", '\n')

But how can it be generic for all control characters?

str:gsub("\\(.)", '\%1') -- doesn't work