try to avoid races again (cf. 8c37cb84065f and fd3a36e48b09);
(* Title: HOL/HOLCF/IOA/ABP/Action.thy
Author: Olaf Müller
*)
header {* The set of all actions of the system *}
theory Action
imports Packet
begin
datatype 'm action =
Next | S_msg 'm | R_msg 'm
| S_pkt "'m packet" | R_pkt "'m packet"
| S_ack bool | R_ack bool
end