Does ECCOMetadata have dates or a date? (Should we use a different design for ECCOMetadata?)

[glwagner]

The docstring says date

ClimaOcean.jl/src/DataWrangling/ECCO/ECCO_metadata.jl

Line 54 in 9c858b0

- `date`: The date of the metadata (default: DateTimeProlepticGregorian(1993, 1, 1)).

but the actual function signature requires dates:

ClimaOcean.jl/src/DataWrangling/ECCO/ECCO_metadata.jl

Line 59 in 9c858b0

dates = DateTimeProlepticGregorian(1993, 1, 1),

I also want to note that I think this design is confusing. The user interface is confusing, and it also makes the source code confusing.

Another design could be to have ECCOMetadata represent a single instance and then use a vector of ECCOMetadata to represent many of them (if that is even necessary).

Anything to make the design more explicit with less hidden suprises.

[glwagner]

I guess another possibility is to discontinue "single date" support, so users just have to write [date] if they want one date.

[NoraLoose]

I can confirm that following the documentation example and using

date  = DateTimeProlepticGregorian(1993, 1, 1)
set!(ocean.model, T = ClimaOcean.ECCOMetadata(:temperature; date),
                  S = ClimaOcean.ECCOMetadata(:salinity; date))

throws an error:

MethodError: no method matching ECCOMetadata(::Symbol; date::DateTimeProlepticGregorian)

Closest candidates are:
  ECCOMetadata(::Symbol; dates, version, dir) got unsupported keyword argument "date"
   @ ClimaOcean /pscratch/sd/n/nloose/depot/packages/ClimaOcean/kTfXn/src/DataWrangling/ECCO/ECCO_metadata.jl:70
  ECCOMetadata(::Symbol, ::Any; ...)
   @ ClimaOcean /pscratch/sd/n/nloose/depot/packages/ClimaOcean/kTfXn/src/DataWrangling/ECCO/ECCO_metadata.jl:78
  ECCOMetadata(::Symbol, ::Any, ::Any; dir) got unsupported keyword argument "date"
   @ ClimaOcean /pscratch/sd/n/nloose/depot/packages/ClimaOcean/kTfXn/src/DataWrangling/ECCO/ECCO_metadata.jl:78
  ...


Stacktrace:
 [1] kwerr(::@NamedTuple{date::DateTimeProlepticGregorian}, ::Type, ::Symbol)
   @ Base ./error.jl:165
 [2] top-level scope
   @ In[23]:1

But changing the syntax to

dates  = DateTimeProlepticGregorian(1993, 1, 1)
set!(ocean.model, T = ClimaOcean.ECCOMetadata(:temperature; dates),
                  S = ClimaOcean.ECCOMetadata(:salinity; dates))

works, as expected.

[glwagner]

I guess the global simulation example uses

date = DateTimeProlepticGregorian(1993, 1, 1)
set!(ocean.model, T=ECCOMetadata(:temperature; dates=date),
                  S=ECCOMetadata(:salinity; dates=date))

If we are ok with this syntax we can close this issue. I guess the basic idea is that we can make metadata representing a range of dates:

julia> dates  = DateTimeProlepticGregorian(1993, 1, 1):Month(1):DateTimeProlepticGregorian(1994, 1, 1)
DateTimeProlepticGregorian(1993-01-01T00:00:00):Month(1):DateTimeProlepticGregorian(1994-01-01T00:00:00)

julia> metadata = ECCOMetadata(:temperature; dates)
ECCOMetadata:
├── name: temperature
├── dates: DateTimeProlepticGregorian(1993-01-01T00:00:00):Month(1):DateTimeProlepticGregorian(1994-01-01T00:00:00)
├── version: ClimaOcean.DataWrangling.ECCO.ECCO4Monthly()
└── dir: /Users/gregorywagner/.julia/scratchspaces/0376089a-ecfe-4b0e-a64f-9c555d74d754/ECCO

Then we can index into that metadata like its a vector:

julia> metadata[1]
ECCOMetadata:
├── name: temperature
├── dates: DateTimeProlepticGregorian(1993-01-01T00:00:00)
├── version: ClimaOcean.DataWrangling.ECCO.ECCO4Monthly()
└── dir: /Users/gregorywagner/.julia/scratchspaces/0376089a-ecfe-4b0e-a64f-9c555d74d754/ECCO

which gives the same thing as building the metadata with a single date.

It doesn't feel like the most natural syntax but it's also not horrible. So maybe we can close this issue.

[glwagner]

Also worth noting that the docstring was fixed at some point:

ClimaOcean.jl/src/DataWrangling/ECCO/ECCO_metadata.jl

Line 63 in 6d3d822

- `dates`: The date(s) of the metadata. Note this can either be a single date,