040000 tree 510c6a145d3ea8b059977f758ed6acfae0191284	ostream.joiner.cons
040000 tree eaa0fa5882994481b115125563393abbe7ef9fba	ostream.joiner.creation
040000 tree 8886428806d38a5d8a7cc99d501692aa70fbb2a9	ostream.joiner.ops