Assume a string {a:b,c:d},{a:b,c:d,e:[{d:e},{f:g}]}. I'd like to parse this into tokens
a:b,c:d a:b,c:d,e:[{d:e},{f:g}] which later can be parsed further.
The regex ({(?:[^{}]++|(?1))*}) produces {a:b,c:d} {a:b,c:d,e:[{d:e},{f:g}]}, but I'm stuck in figuring out how to match on the enclosing {} without including them in the result. (The string may contain even deeper recursion elements not shown in the example)
You need to capture the part of the regex you need to extract from the match:
{((?:[^{}]++|(?R))*)}
^_________________^
These parentheses create Group 1 that will hold the value you can access using your programming language.
Once you get the matches, you may run a second pass to extract a:b or a:[...] substrings using
[^,[]+(?:\[[^][]+])?
See the regex demo. Details:
[^,[]+ - zero or more chars other than [ and comma(?:\[[^][]+])? - an optional sequence of [, then one or more chars other than [ and ] and then a ].