diff --git a/src/turtle_lexer.l b/src/turtle_lexer.l
index c2f249b..f133747 100644
--- a/src/turtle_lexer.l
+++ b/src/turtle_lexer.l
@@ -381,9 +381,13 @@ EXPONENT [eE][+-]?[0-9]+
                while(1) {
                   int c = yytext[yyleng - 1];
                   if(c == '{' || c == ' ' || c=='\t' || c == '\v' || c == '\n' ||
-                     c == ':' || c == '-') {
+                     c == '=' ) {
                     yyleng--;
-                  } else
+                  } 
+                  else if ( yyleng >= 2 && ( c == '-' && yytext[yyleng - 2] == ':' ) ) { 
+                    yyleng -= 2;
+                  }
+                  else
                     break;
                 }
                 yytext[yyleng] = '\0';