For the sake of mentioning... have a look at my proposal:
http://igagis.github.io/stob/
It is very simple and is not overloadad with variety of special symbols, just {} and "" basically.
Supports C++ style comments.
There are C++, C# and Java libraries.
Example:
"String object"
AnotherStringObject
"String with children"{
"child 1"
Child2
"child three"{
SubChild1
"Subchild two"
Property1 {Value1}
"Property two" {"Value 2"}
//comment
/* multi-line
comment */
"multi-line
string"
"Escape sequences \" \n \r \t \\"
}
}