opip: pass through forms in the op family.

* stdlib/op.tl (sys:opip-expand): Add op, do, lop, ldo, ap,
ip, ado, ido, ret and aret to the operators whose forms are
passed through untransformed. This is important because it
lets us override the implicit (op ...) and (do ...) chosen
by the expander. When a pipeline element produces a list, for
instance, we want to be able to use (ap ...) in the next
element to spread the list into arguments.

* tests/012/op.tl: Add bellied numbers test case.

* txr.1: Documented.

0 files changed, 0 insertions, 0 deletions