Reset flex scanner if exception thrown during read.

We must tear down and rebuild the Flex scanner, otherwise
it is left in a bad state causing it to abort.

* parser.c (parser_cleanup): After destroying scanner,
null out the pointer.
(parser_reset): Destroy the Flex scanner, and
instantiate a new one in its place.
(lisp_parse): Set up an unwind catch which will
reset the parser if it was aborted by an exception.

* parser.h (parser_reset): Declared.

1 files changed, 1 insertions, 0 deletions

diff --git a/parser.h b/parser.h
index bc6a3364..efbaa351 100644
--- a/parser.h
+++ b/parser.h
@@ -86,6 +86,7 @@ int parse(parser_t *parser, val name, enum prime_parser);
 val source_loc(val form);
 val source_loc_str(val form, val alt);
 val rlset(val form, val info);
+void parser_reset(parser_t *);
 INLINE val rlcp(val to, val from)
 {
   return rlset(to, source_loc(from));