bool functions retrofitted for eval change

ast/token.go

@@ -130,6 +130,17 @@ func (t *Token) FmtToken() string {
     }
 }
 
+/* Sets the string value for a non-list token
+ */
+func (t *Token) Set(arg string) bool {
+    if t.Tag == LIST {
+        return false
+    }
+
+    t.inner = arg
+    return true
+}
+
 /* Returns a tag in text
  */
 func GetTagAsStr(tag Token_t) string {