kip
"Adjusting" calling context of a function
Best explained by an example. Lets say I want to call:
Calendar.ISO.naive_datetime_to_string(year, month, day, hour, minute, second, microsecond)
From another calendar module that implements @behaviour Calendar. Calendar.ISO.naive_datetime_to_string calls time_to_string(hour, minute, second, microsecond) under the covers, resolved to be in the Calendar.ISO module.
But … it also calls date_to_string(year, month, day) which I’d like to be called as the version in my Calendar module.
I don’t think this is possible (and quite possible its even “bad”) but I’ve found a few situations where I’d like to delegate a function call to another module, but have the inner functions be resolved to my module. Behaviour-based modules is quite a good example of where this can crop up I think,
First Post!
peerreynders
What’s wrong with :
@impl true
def naive_datetime_to_string(year, month, day, hour, minute, second, microsecond) do
date_to_string(year, month, day) <> " " <> Calendar.ISO.time_to_string(hour, minute, second, microsecond)
end
and use that instead of Calendar.ISO.naive_datetime_to_string? i.e. provide the alternate implementation where desired and only use the original implementation where needed.
In a way you seem to be looking for dynamic dispatch of a polymorphic operation typically implemented in class-based languages.
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