JLD and package extensions

General Usage
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3

After a good nights sleep, I discovered that the solution is really simple:

module Abc

export Ab, JLDExt

struct Ab
    a
end

function set_jldext(m)
    global JLDExt = m
    @info "JLDExt set to '$JLDExt'"
end

end # module Abc

module JLDExt

using Abc, JLD
import JLD.writeas
import JLD.readas

struct JLDAb
    a
end

JLD.writeas(x::Ab) = writeas(JLDAb(x.a))
JLD.readas(x::JLDAb) = Ab(x.a)

function __init__()
    Abc.set_jldext(JLDExt)
    @info "Loaded JLDExt"
end

end

using Test, Abc, JLD

@testset "JLD" begin
    x = Ab(1)
    fname = "/tmp/JLD_test.jld"
    save(fname, "x", x)
    @test load(fname)["x"] == x
end

Full code available at GitHub - GHTaarn/Abc.jl at good_fix