+AT_CHECK([bison -o input.c input.y])
+AT_COMPILE([input.o], [-c input.c])
+AT_CLEANUP
+
+
+
+## -------------------- ##
+## Characters Escapes. ##
+## -------------------- ##
+
+
+AT_SETUP([Characters Escapes])
+
+AT_DATA_GRAMMAR([input.y],
+[%{
+void yyerror (const char *s);
+int yylex (void);
+%}
+[%%
+exp:
+ '\'' "\'"
+| '\"' "\""
+| '"' "'"
+;
+]])
+# Pacify font-lock-mode: "
+
+AT_CHECK([bison -o input.c input.y])