RFC on SimpleDOM: simple, unified access to json, xml, yaml, ini, etc.

[lihuiba]

SimpleDOM emphasizes on

• simple & convenient usage
• unified interface, common needs (may not fit for corner cases)
• efficient parsing (reading), as well as compiling (of applications)

Planned style for usage:

auto doc = parse(buf, size, DOC_JSON)->wrapper();
auto a = doc["asdf"].to_string();
auto j = doc["jkl"].to_integer();
auto fb = doc["foo"]["bar"];
for (auto x: fb.enumerable_children()) {
    // ...
}
for (auto x: fb.enumerable_same_key_siblings()) {
    // ...
}

Check out https://github.com/alibaba/PhotonLibOS/pull/259/files for details