Some questions regarding the API

[francoisthire]

I have some questions regarding the API:

• The API exposes modules D, I, and ID with generic functions. It seems redundant. Why not just have generic functions?
• Considering the lack of conversion functions from string to encoded or hash, it seems that modules D, I or ID seems not usable in practice.
• For the generic functions, Why does the hash function return both a hash and an encoded datatype? It seems only the second one can be used with verify.
• More generally, what are the differences between a hash and encoded? Why not just use one datatype?
• I am wondering why the hash function takes an encoded_len argument. It seems that this value comes from the function encoded_len. Wouldn't be simpler to not expose encoded_len and let the function hash compute this length by itself?