QST: ExtensionDtype with complex arguments
#### Question about pandas

I am trying to add support to store columns of functional data in Pandas. This kind of data requires that the associated dtype store some information, such as the discretization points for discretized functions, which is not as simple as the arguments in other ExtensionDtypes (for example, in this case would be a numpy array). This presents several challenges:

- The `ExtensionDtype` will not be hashable unless I take extra steps to make it so, hashing numpy arrays like in the Categorical dtype.
- If the name of the dtype has to include the value of the arguments it would be unreadable.
- `construct_from_string` should have to parse a lot of structured information (maybe possible using `eval`, but what is the point?). I would prefer that my `ExtensionDtype` could not be constructed from a string. However, at least one test require the dtype to be constructable from its name.

What suggestions do you have to solve these kind of problems?