open tactic bool

example (a b : nat) (H : a + b = 0) : a = a :=
by do
  H ← get_local "H",
  t ← infer_type H,
  trace_expr t,
  set_bool_option ("pp" <.> "all") tt,
  trace "after pp.all true",
  trace_expr t,
  rfl ← mk_const "rfl",
  apply rfl

print "set_bool_option tactic does not affect other commands"
check (0:nat) + 1