Split string on commas ignoring commas, brackets, braces in parenthesis, quotes - regex

Question

I am attempting to split a comma separated list. I want to ignore commas that are in parenthesis, brackets, braces and quotes using regex. To be more precise I am trying to do this in postgres POSIX regexp_split_to_array.
My knowledge of regex is not great and by searching on stack overflow I was able to get a partial solution, I can split the string if it does not contain nested parenthesis, brackets, braces. Here is the regex:
,(?![^()]*+\))(?![^{}]*+})(?![^\[\]]*+\])(?=(?:[^"]|"[^"]*")*$)
Test case:
0, (1,2), (1,2,(1,2)) [1,2,3,[1,2]], [1,2,3], "text, text (test)", {a1:1, a2:3, a3:{a1=1, s2=2}, a4:"asasad, sadsas, asasdasd"}
Here is the demo
The problem is that in i.e. (1,2,(1,2)) the first 2 commas get matched if there is a nested parenthesis.

Answer 1

Even though regex is not the best way to go, here is a solution with recursive matching:
(?>(?>\([^()]*(?R)?[^()]*\))|(?>\[[^[\]]*(?R)?[^[\]]*\])|(?>{[^{}]*(?R)?[^{}]*})|(?>"[^"]*")|(?>[^(){}[\]", ]+))(?>[ ]*(?R))*
If we break it down, there is a group with some stuff inside, followed by more of the same kind of matching, separated by optional spaces.
(?> <---- start matching
... <---- some stuff inside
) <---- end matching
(?>
[ ]* <---- optional spaces
(?R) <---- match the entire thing again
)* <---- can be repeated
From your example 0, (1,2), (1,2,(1,2)) [1,2,3,[1,2]], [1,2,3],..., we want to match:
0
(1,2)
(1,2,(1,2)) [1,2,3,[1,2]]
[1,2,3]
...
For the third match, the stuff inside will match (1,2,(1,2)) and [1,2,3,[1,2]], which are separated by a space.
The stuff inside is a series of options:
(?>
(?>...)| <---- will match balanced ()
(?>...)| <---- will match balanced []
(?>...)| <---- will match balanced {}
(?>...)| <---- will match "..."
(?>...) <---- will match anything else without space or comma
)
Here are the options:
\( <---- literal (
[^()]* <---- any number of chars except ( or )
(?R)? <---- match the entire thing optionally
[^()]* <---- any number of chars except ( or )
\) <---- literal )
\[ <---- literal [
[^[\]]* <---- any number of chars except [ or ]
(?R)? <---- match the entire thing optionally
[^[\]]* <---- any number of chars except [ or ]
\] <---- literal ]
{ <---- literal {
[^{}]* <---- any number of chars except { or }
(?R)? <---- match the entire thing optionally
[^{}]* <---- any number of chars except { or }
} <---- literal }
" <---- literal "
[^"]* <---- any number of chars except "
" <---- literal "
[^(){}[\]", ]+ <---- one or more chars except comma, or space, or these: (){}[]"
Note that this does not match a comma-separated list, but the items in such a list. The exclusion of comma and space in the last option above causes it to stop matching at comma or space (except for space we explicitly allowed between repeated matches).