+# include <stdbool.h>
+
+
+
+/*-------------.
+| Assertions. |
+`-------------*/
+
+/* In the past, Bison defined aver to simply invoke abort in the case of
+ a failed assertion. The rationale was that <assert.h>'s assertions
+ were too heavyweight and could be disabled too easily. See
+ discussions at
+ <http://lists.gnu.org/archive/html/bison-patches/2006-01/msg00080.html>
+ <http://lists.gnu.org/archive/html/bison-patches/2006-09/msg00111.html>.
+
+ However, normal assert output can be helpful during development and
+ in bug reports from users. Moreover, it's not clear now that
+ <assert.h>'s assertions are significantly heavyweight. Finally, if
+ users want to experiment with disabling assertions, it's debatable
+ whether it's our responsibility to stop them. See discussion
+ starting at
+ <http://lists.gnu.org/archive/html/bison-patches/2009-09/msg00013.html>.
+
+ For now, we use assert but we call it aver throughout Bison in case
+ we later wish to try another scheme.
+*/
+# include <assert.h>
+# define aver assert