Lua regular expression with exactly one match

Question

can someone help me with lua "regex" aka patterns?

How do I translate this regex into a lua pattern for string.match(): ytplayer\.config\s*=\s*(\{.+?\});. You can use this site for an explanation what this regex does: https://regex101.com/#pcre

Essentially I want to look for a string which starts with ytplayer.config = (note the possible whitespace before and after equal sign), followed by a { and until we hit a semicolon.

ytplayer.config = {a lot of text, special characters and everything else which is possible...}}; this could be a result.

At the moment I have string.match(s, "ytplayer.config%s=%s({.});") but it returns an exact copy (checked with kdiff).

Answer 1

Have a look, this will return your captured group:

print(string.match("ytplayer.config = {a lot of text, special characters and everything else which is possible...}};", "^ytplayer%.config%s*=%s*({.-});"))

Output:

{a lot of text, special characters and everything else which is possible...}}

The regex is ^ytplayer%.config%s*=%s*({.-});. In case you do not want check for a string start, remove ^ from the beginning.

Please see this demo.

In Lua patterns, % escspes "magic symbols". Like *, the modifier - also matches zero or more occurrences of characters of the original class. However, instead of matching the longest sequence, it matches the shortest one.