_BoundaryConditions() v BoundaryConditions()

[christophernhill]

@ali-ramadhan should this line

https://github.com/ali-ramadhan/Oceananigans.jl/blob/master/src/model.jl#L25

be

boundary_conditions = _BoundaryConditions(:periodic, :periodic, :rigid_lid, :free_slip)

instead of

boundary_conditions = BoundaryConditions(:periodic, :periodic, :rigid_lid, :free_slip)

?

[ali-ramadhan]

Yes! Thanks for catching this.

Yeah it's ugly because I was trying to have some input sanitation before creating the boundary conditions struct but BoundaryConditions(:periodic, :periodic, :rigid_lid, :free_slip) would have conflicted with the default struct constructor.

There must be some way of doing this nicely but I don't know enough Julia right now...

[vchuravy]

Should be a perfect example of a inner constructor (which I really only recommend for input sanitization and invariants checking).

struct BoundaryConditions
    x_bc::Symbol
    y_bc::Symbol
    top_bc::Symbol
    bottom_bc::Symbol

    function BoundaryConditions(x_bc, y_bc, top_bc, bottom_bc)
        @assert x_bc == :periodic && y_bc == :periodic "Only periodic horizontal boundary conditions are currently supported."
        @assert top_bc == :rigid_lid "Only rigid lid is currently supported at the top."
        @assert bottom_bc in [:no_slip, :free_slip] "Bottom boundary condition must be :no_slip or :free_slip."
        new(x_bc, y_bc, top_bc, bottom_bc)
    end
end

Instead of Symbols you can also use @enum, but that is a stylistic choice.

[ali-ramadhan]

Thanks for the tip, did not know about inner constructors!