This would be a really nice feature.

Would it make sense for the computation function to take the (partially-initialized) f as input?

So, e.g., something like this:

function compute_double end
@lazy struct LazyDoubler
    x::Int
    @lazy double_of_x::Int = compute_double
end
LazyDoubler(x::Int) = LazyDoubler(x, uninit)
compute_double(foo::LazyDoubler) = foo.x + foo.x

bar = LazyDoubler(3)
bar.double_of_x # this will be computed on-demand, and the result will be 6

I wonder if this is not better:

@lazy @kwdef struct Foo
    x::Int = 3
    @lazy field::Int = compute()
end

I also think that indeed adding @kwdef somewhere inside the macro could solve the issue maybe

actually the @kwdef macro requires keywords argument for the unitialized fields so it is not the same feature requested here, but I think that making @lazy compatible with @kwdef is nonetheless a good feature

I am not sure if this is related, but would it make sense to support get(<lazystruct>,:<lazyprop>,<lazydefault>) when isinit(<lazystruct>,:<lazyprop>) == true returns <lazyprop> when false returns <lazydefault> ?