proper support for "isabelle update -D DIR": avoid accidental exclusion of select_dirs (amending e5dafe9e120f);
(* Title: HOL/HOLCF/IOA/ABP/Packet.thy
Author: Olaf Müller
*)
section \<open>Packets\<close>
theory Packet
imports Main
begin
type_synonym
'msg packet = "bool * 'msg"
definition
hdr :: "'msg packet => bool" where
"hdr = fst"
definition
msg :: "'msg packet => 'msg" where
"msg = snd"
end