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desihub / desisurvey

Code for desi survey planning and implementation
BSD 3-Clause "New" or "Revised" License
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update/document how to change Configuration object parameters #49

Closed sbailey closed 7 years ago

sbailey commented 7 years ago

Document how to change Configuration object parameters after they have already been read from the yaml config file. e.g. for changing the start date:

c.first_day._value = desisurvey.utils.get_date(...)

Please update the interface to make that more obvious and not require _private variables. Changing the start/stop dates is a specific case, but in general we should support the ability to algorithmically change any config variable without having to go via a custom yaml file.

dkirkby commented 7 years ago

The currently supported method to change a config param in memory is:

  c.first_day._value = <DATE>

However, this operation should not normally be necessary (except, e.g. for specialized testing code) so is reserved for experts. Therefore I consider it a feature, not a bug, that the following does not work:

  c.first_day = <DATE>

I could hide the _value attribute by adding a method, e.g.

  c.first_day.set_value(<DATE>)

but wanted to check back with you to see your current thinking first.

sbailey commented 7 years ago

OK for c.first_day.set_value(<DATE>) if you prefer that over c.first_day = <DATE>.

Even if it is primarily to support simulations/verification/testing, we should have a way to override a config file value that doesn't carry the implied "this might break later" message of telling users to use a private _value variable.

dkirkby commented 7 years ago

The new set_value() method is implemented now in #66, with accompanying docstring and unit test updates. I also updated earlier instances of _value = X to use set_value(X).