Why not add a cache to optimize performance

[XuJianxing]

Hi , I'm using ymal-cpp in my program. I found the performance of reading yaml config is relatively low. So why not add a cache in as_if function to avoid convert::decode each time?

[KitsuneRal]

I tried caching in my wrapper around yaml-cpp - it adds (non-trivial) overhead of cache management (memory allocations, in particular) but you don't save that much on repeated reads unless there are quite a few repeated reads and what you're reading is not std::string. Depending on the use case, you may or may not want caching but I figure that most of the time it's not that hard to add a caching overlay if you really need it. In my cases, I implemented an in-memory typesafe structure that I read YAML into, and that worked much better than caching.

[SGSSGene]

I understand benefits of this feature request, but currently this is out of scope of the library design and what we as developers can support.