2 files changed, 4 insertions(+), 2 deletions(-)

M eval.ha
M lex.ha

@@ 49,7 49,7 @@ fn eval(st: *state, e: *expr) (rational::number | noresult | invalid) = {
 	case let i: rational::number =>
 		return i;
 	case let r: reference =>
-		if (r == -1) {
+		if (r == REFERENCE_LAST) {
 			if (len(st.results) == 0) {
 				return invalid;
 			};

@@ 23,6 23,8 @@ type name = str;
 type token = ((i64, uint) | dot | reference | sqrt_keyword | option_keyword
 	| name | groupstart | groupend | bang | operation | io::EOF);
 
+def REFERENCE_LAST: reference = -1;
+
 // Invalid token
 type invalid = !void;
 


@@ 130,7 132,7 @@ fn next_token(lex: *lexer) (token | invalid) = {
 			match (strings::next(&lex.iter)) {
 			case let r: rune =>
 				if (r == '$') {
-					return -1: reference;
+					return REFERENCE_LAST;
 				};
 				strings::prev(&lex.iter);
 			case done =>