:duration category -> conversion of :year to :weeks/:days not working

[DamienFriot]

Hi,

While :week and :day are compatible units, this is not the case for :year (but it is compatible with month).

Is it on purpose?

Thanks in advance for your answer.

[kipcole9]

Yes, its by design in CLDR. Convertability is based upon units that have a common base unit. And not all time elements have the same base unit. For example:

iex> Cldr.Unit.base_unit :day
{:ok, :second}
iex> Cldr.Unit.base_unit :week
{:ok, :second}
iex> Cldr.Unit.base_unit :hour 
{:ok, :second}
iex> Cldr.Unit.base_unit :minute
{:ok, :second}
iex> Cldr.Unit.base_unit :second
{:ok, :second}

iex> Cldr.Unit.base_unit :year
{:ok, :year}
iex> Cldr.Unit.base_unit :month
{:ok, :year}

You can see that :day: and :week are defined in terms of :second. :year and :month are defined in terms of :year.

The reason for that is, as I'm sure you understand, that years and months are variable in length so the conversion would need to have context that isn't available. Even as it is, the conversions with this library assume a year has 12 months - which isn't true for all calendars.

My ex_cldr_dates_times is a lot more aware of durations so if you let me know what the use case is I may have another way to help you achieve it.

[DamienFriot]

Thanks for your answer.
I will look at ex_cldr_dates_times and come back to you if needed but I think this will ok.
Sorry for bothering you with that.

[kipcole9]

Will close this issue now since the code is working as expected - even if not as hoped for.