Export @compute at the top level

[tomchor]

I wonder what people think of this. I find this macro really useful and always find myself using it, getting an error that @compute is not defined, and then (properly) using it!

[simone-silvestri]

As I understand now, @compute is equivalent to compute!.
i.e.

@compute f = Field(op)

is equivalent to

f = compute!(Field(op))

I think a good change would be to make @compute also construct the field, in practice, having

f = @compute op

as to cover another functionality that can be exported

[glwagner]

What about calling compute! in the Field constructor?

[simone-silvestri]

Sounds like a good idea. We could add a keyword argument to

Oceananigans.jl/src/AbstractOperations/computed_field.jl

Lines 38 to 50 in 925f4c9

	function Field(operand::OperationOrFunctionField;
	data = nothing,
	indices = indices(operand),
	boundary_conditions = FieldBoundaryConditions(operand.grid, location(operand)),
	recompute_safely = true)
	grid = operand.grid
	loc = location(operand)
	indices = validate_indices(indices, loc, grid)
	@apply_regionally boundary_conditions = FieldBoundaryConditions(indices, boundary_conditions)
	if isnothing(data)

which defaults to true.

[glwagner]

See #4531

[tomchor]

Superseded by #4531