diff --git a/src/role.h b/src/role.h
index 28a49ba..5244c25 100644
--- a/src/role.h
+++ b/src/role.h
@@ -8,9 +8,7 @@
 #include "constraint.h"
 #include "states.h"
 
-#define	READ	1
-#define SEND	2
-#define CLAIM	3
+enum eventtype { READ, SEND, CLAIM };
 
 //! The container for the claim info list
 struct claimlist
diff --git a/src/symbol.h b/src/symbol.h
index 2edf306..0194295 100644
--- a/src/symbol.h
+++ b/src/symbol.h
@@ -6,11 +6,7 @@
  */
 #define HASHSIZE 997
 
-#define T_UNDEF		-1
-#define T_PROTOCOL	0
-#define T_CONST		1
-#define T_VAR		2
-#define T_SYSCONST	3
+enum symboltypes { T_UNDEF = -1, T_PROTOCOL, T_CONST, T_VAR, T_SYSCONST };
 
 #define EOS 0
 
diff --git a/src/tac.h b/src/tac.h
index a8cf871..d9f3a36 100644
--- a/src/tac.h
+++ b/src/tac.h
@@ -7,26 +7,28 @@
  * TAC instructions
  */
 
-#define TAC_UNDEF	0
-#define TAC_SYM		1
-#define TAC_TUPLE	3
-#define TAC_ENCRYPT	4
-#define TAC_VAR		7
-#define TAC_CONST	8
-#define TAC_READ	9
-#define TAC_SEND	10
-#define TAC_CLAIM	11
-#define TAC_FUNC	12
-#define TAC_STRING	13
-#define TAC_ROLE	14
-#define TAC_PROTOCOL	15
-#define TAC_RUN		16
-#define TAC_ROLEREF	17
-#define TAC_SECRET	18
-#define TAC_INVERSEKEYS	19
-#define TAC_UNTRUSTED	20
-#define TAC_COMPROMISED	21
-#define TAC_USERTYPE	22
+enum tactypes {
+  TAC_UNDEF,
+  TAC_SYM,
+  TAC_TUPLE,
+  TAC_ENCRYPT,
+  TAC_VAR,
+  TAC_CONST,
+  TAC_READ,
+  TAC_SEND,
+  TAC_CLAIM,
+  TAC_FUNC,
+  TAC_STRING,
+  TAC_ROLE,
+  TAC_PROTOCOL,
+  TAC_RUN,
+  TAC_ROLEREF,
+  TAC_SECRET,
+  TAC_INVERSEKEYS,
+  TAC_UNTRUSTED,
+  TAC_COMPROMISED,
+  TAC_USERTYPE
+};
 
 struct tacnode
 {
diff --git a/src/tracebuf.h b/src/tracebuf.h
index 435634d..f7aa71e 100644
--- a/src/tracebuf.h
+++ b/src/tracebuf.h
@@ -7,11 +7,12 @@
 #include "system.h"
 
 /* STATUS symbols */
-#define S_UNK 0 // UNKnown   : unprocessed.
-#define S_OKE 1 // OKE       : done, but required for the attack.
-#define S_RED 2 // REDundant : is not needed for attack, we're sure.
-#define S_TOD 3	// TODo      : The previous suggestion REQ was too similar to RED.
-		//             This is reserved for reads.
+enum statussymbols {
+  S_UNK,	// UNKnown   : unprocessed.
+  S_OKE,	// OKE       : done, but required for the attack.
+  S_RED,	// REDundant : is not needed for attack, we're sure.
+  S_TOD 	// TODo      : The previous suggestion REQ was too similar to RED. This is reserved for reads.
+};
 
 
 /*