$abc = "abc,xyz,{1,2,3,4},18-90-89,{{1,2},{5,6,7,8}},yts";

$par=qr! \{ (?: [^{}]+ | (??{ $par }) )+ \} !x;

@a= $abc=~ /([^{,]+|$par)/g;

print join("\n",@a);