Reexport

Maybe you have a module X that depends on module Y and you want using X to pull in all of the symbols from Y. Maybe you have an outer module A with an inner module B, and you want to export all of the symbols in B from A. It would be nice to have this functionality built into Julia, but we have yet to reach an agreement on what it should look like (see JuliaLang/julia#1986). This short macro is a stopgap we have a better solution.

@reexport using <modules> calls using <modules> and also re-exports their symbols:

module Y
    ...
end

module Z
    ...
end

module X
    using Reexport
    @reexport using Y
    # all of Y's exported symbols available here
    @reexport using Z: x, y
    # Z's x and y symbols available here
end

using X
# all of Y's exported symbols and Z's x and y also available here

@reexport import <module>.<name> or @reexport import <module>: <name> exports <name> from <module> after importing it.

module Y
    ...
end

module Z
    ...
end

module X
    using Reexport
    @reexport import Y
    # Only `Y` itself is available here
    @reexport import Z: x, y
    # Z's x and y symbols available here
end

using X
# Y (but not its exported names) and Z's x and y are available here.

@reexport module <modulename> ... end defines module <modulename> and also re-exports its symbols:

module A
    using Reexport
    @reexport module B
    	...
    end
    # all of B's exported symbols available here
end

using A
# all of B's exported symbols available here

@reexport @another_macro <import or using expression> first expands @another_macro on the expression, making @reexport with other macros.

@reexport begin ... end will apply the reexport macro to every expression in the block.