Hi,

I summrized (not completed) creation/conversion methods/functions for
each types.

https://docs.google.com/a/heroku.com/spreadsheets/d/1TgU-CIGi5zfsDm127aCnx0qgAq5nY9Ufn117jNHHCOQ/edit?usp=sharing

Feel free to use/complement/fix it.

As you can see, (especially) C function names are not consistent.

Thanks,
Koichi

-- 
// SASADA Koichi at atdot dot net