-extern const char *skeleton; /* for -S */
-extern const char *include; /* for -I */
-
-extern int debug_flag; /* for -t */
-extern int defines_flag; /* for -d */
-extern int locations_flag;
-extern int no_lines_flag; /* for -l */
-extern int no_parser_flag; /* for -n */
-extern int token_table_flag; /* for -k */
-extern int graph_flag; /* for -g */
-extern int yacc_flag; /* for -y */
+
+/* for -S */
+extern char const *skeleton;
+
+/* for -I */
+extern char const *include;
+
+extern bool debug_flag; /* for -t */
+extern bool defines_flag; /* for -d */
+extern bool locations_flag;
+extern bool no_lines_flag; /* for -l */
+extern bool no_parser_flag; /* for -n */
+extern bool token_table_flag; /* for -k */
+extern bool graph_flag; /* for -g */
+extern bool yacc_flag; /* for -y */
+
+/* GLR_PARSER is true if the input file says to use the GLR
+ (Generalized LR) parser, and to output some additional information
+ used by the GLR algorithm. */
+
+extern bool glr_parser;
+
+/* PURE_PARSER is true if should generate a parser that is all pure
+ and reentrant. */
+
+extern bool pure_parser;
+
+/* NONDETERMINISTIC_PARSER is true iff conflicts are accepted. This
+ is used by the GLR parser, and might be used in BackTracking
+ parsers too. */
+
+extern bool nondeterministic_parser;