New --yydebug option.

* parser.y (have_yydebug): New global constant.
(yydebug_onoff): New function.

* parser.h (have_yydebug, yydebug_onof): Declared.
(yydebug_onoff): New function.

* txr.c (help): List --yydebug option.
(txr_main): --yydebug option implemented.

1 files changed, 9 insertions, 0 deletions

diff --git a/parser.y b/parser.y
index 54cc494b..983b05c9 100644
--- a/parser.y
+++ b/parser.y
@@ -1039,6 +1039,8 @@ not_a_clause : ALL              { $$ = mkexp(all_s, nil, num(parser->lineno)); }
 
 %%
 
+const int have_yydebug = YYDEBUG;
+
 int yylex(YYSTYPE *, yyscan_t scanner);
 
 /* C99 inline instantiations. */
@@ -1046,6 +1048,13 @@ int yylex(YYSTYPE *, yyscan_t scanner);
 val rlcp(val to, val from);
 #endif
 
+void yydebug_onoff(int val)
+{
+#if YYDEBUG
+  yydebug = val;
+#endif
+}
+
 static val sym_helper(parser_t *parser, wchar_t *lexeme, val meta_allowed)
 {
   scanner_t *scnr = parser->scanner;