瞎扯淡 Oj.dump 一个 NaN 会出现 PI
发现一个有趣的现象
# ruby 2.3.1p112 (2016-04-26 revision 54768) [x86_64-darwin14]
# oj (2.18.0)
2.3.0 :006 > Oj.dump({a: (0 / 0.to_f)})
=> "{\":a\":3.3e14159265358979323846}"
用超过上限的数字来表示 NaN，保证 dump 回来的数据能正常显示 NaN？哈哈哈哈
https://github.com/ohler55/oj/blob/cecfe196af51e8fc964cd6d9751e50724f1cb8bf/ext/oj/oj.h#L73
#define INF_VAL "3.0e14159265358979323846"
#define NINF_VAL "-3.0e14159265358979323846"
#define NAN_VAL "3.3e14159265358979323846"