val before_prim : t ‑> ('a, 'b) Shexp_process.Prim.t ‑> ('a, 'b) Shexp_process.Prim.Args.t ‑> ('a, 'b) prim_tokenCalled before the execution of a primitive. The S-expression is a representation of
the primitive call, for instance (mkdir "foo").
val after_prim : t ‑> ('a, 'b) Shexp_process.Prim.t ‑> ('b, exn * Printexc.raw_backtrace) Pervasives.result ‑> ('a, 'b) prim_token ‑> unitCalled after the execution of a primitive, with the result.
val user_exn : t ‑> exn ‑> Printexc.raw_backtrace ‑> unitRegister a user exception, i.e. when a bind raises.
val enter_sub : t ‑> unitShexp tries to linearize the trace as much as possible. When an execution parameter
is changed locally, such as in (chdir ...) >>= ..., a sub context is entered.
val leave_sub : t ‑> unit