Add a macro for enumeration.

"enum" is like "const" but uses variables instead. This might not be desired.

It has been moved to the top of macros.asm so that included macros can be enumerated.

macros.asm

@@ -1,3 +1,5 @@
+INCLUDE "macros/enum.asm"
+
 INCLUDE "macros/event.asm"
 INCLUDE "macros/sound.asm"
 INCLUDE "macros/text.asm"
@@ -113,17 +115,6 @@ endanim: MACRO
 	ENDM
 
 
-; Constant enumeration
-
-const_def: MACRO
-const_value SET 0
-ENDM
-
-const: MACRO
-\1 EQU const_value
-const_value SET const_value + 1
-ENDM
-
 
 sine_wave: MACRO
 ; \1: amplitude

macros/enum.asm

@@ -0,0 +1,31 @@
+; Enumerate variables
+
+enum_start: macro
+if _NARG >= 1
+__enum__ = \1
+else
+__enum__ = 0
+endc
+if _NARG >= 2
+__enumdir__ = \2
+else
+__enumdir__ = +1
+endc
+endm
+
+enum: macro
+\1 = __enum__
+__enum__ = __enum__ + __enumdir__
+endm
+
+
+; Enumerate constants
+
+const_def: MACRO
+const_value = 0
+ENDM
+
+const: MACRO
+\1 EQU const_value
+const_value = const_value + 1
+ENDM