Lua non-greedy version of +

Question

I have to match /home/user/file.lib both in

bibliography: /home/user/file.lib

as well as

bibliography: "/home/user/file.lib"

in Lua.

The best I came up with is:

> s1 = "bibliography: /home/user/file.lib"
> s2 = 'bibliography: "/home/user/file.lib"'
> string.match(s1, 'bibliography: "?(%g+)"?')
/home/user/file.lib
> string.match(s2, 'bibliography: "?(%g+)"?')
/home/user/file.lib"

But the last match contain a trailing ".

It looks like I need a non-greedy version of the + operator, and it looks like Lua doesn't have it.

How can I achieve my purpose?

Answer 1

Since %g+ matches one or more printable chars and " is also a printable char. So, you need to match any printable characters other than ":

s1 = "bibliography: /home/user/file.lib"
s2 = 'bibliography: "/home/user/file.lib"'
print(string.match(s1, 'bibliography: "?([^%G"]+)"?'))
-- /home/user/file.lib
print(string.match(s2, 'bibliography: "?([^%G"]+)"?'))
-- /home/user/file.lib

See the Lua demo.

The [^%G"]+ pattern matches one or more characters (+) other than non-printable chars (%G) and ".