Then, in a ternary alternative { }+{ }+{ },
- leftmost choice (Inleft Left) is (Some true),
- middle choice (Inleft Right) is (Some false),
- rightmost choice (Inright) is (None)
To preserve its laziness, andb is normally expanded.
Let's rather use the ocaml &&
In order to avoid annoying build dependencies the actual
extraction is only performed as a test in the test suite.