Option interface: 1st try (WIP)

[DavidMStraub]

Motivated by #13.

@peterstangl, the set_option/get_option methods are motivated by pandas... do you find the interface intuitive?

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[peterstangl]

The distinction between _default_options and _options is not 100% clear to me. So I would think that _default_options is used to specify (in the code, not by the user) which options should be available and what default values they should have. On the other hand, _options is used to store any changes to the default option values as done by the user. So this would make totally sense for me.

What is not clear to me is what the use of set_default_option is. This method allows the user to change the _default_options. I don't see a use case for this, as it should be enough for the user to set the _options by using set_option (while I think _default_options should only be changed directly inside the code). set_default_option would also allow the user to add new options to _default_options that do not have any effect (bypassing _option_check_key).

You probably have some use case in mind for set_default_option, but like it is implemented at the moment it might be confusing for the user to decide whether to use set_default_option or set_option to actually change the option value. Thus, I would drop the set_default_option method to make it clear that options should be changed by the user using set_option.

Is there actually something like set_default_option in pandas and how is it used?

[peterstangl]

Sorry, I missed that set_default_option is a class method. But perhaps in that case, one could call it something like with_default_option since it can be used to construct Wilson instances with the specified default option. This would perhaps make the distinction from the set_option method clearer and possibly avoid some confusion (that I had...).

[DavidMStraub]

Basically when set_default_option is called, the default options are modified, which are a class property. This means that they will be changed for all future instances of Wilson. Use case: say you want to perform your analysis always with a specific value of some input parameter. Rather than having to call set_option on each and every instance after instantiating it, you could then simply call

import wilson
wilson.Wilson.set_default_option(...)

and no longer worry about it.

The problem I can see with this is that set_default_option can also be called on the instance, not just on the class, which might indeed be confusing as it affects the class, not just the instance. Not sure how to prevent that ...

[peterstangl]

As implemented at the moment, calling set_default_option not only changes the default option for all future instances of Wilson, but also for all already defined instances. So this also changes the result of their get_option method as long as their method set_option has not been called before. I think this might be confusing, but could easily be prevented by calling set_option on initialization.

[DavidMStraub]

Good point. At first I thought it would be better to also change existing instances, but this is indeed problematic since they will have cached results with the old default parameters. Good idea to call set_option in init.

[DavidMStraub]

OK done. Can you please rebase #13 onto this branch?

[DavidMStraub]

OK let's work with this interface, the config validation can be added later.