5 files changed, 72 insertions, 28 deletions

diff --git a/ChangeLog b/ChangeLog
index 367c2506..016c7ac4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,28 @@
+2015-07-09  Kaz Kylheku  <kaz@kylheku.com>
+
+	Parser cleanup: embed scanner in parser.
+
+	* parser.c (parser_destroy): New GC finalizer static function.
+	(parser_ops): Register parser_destroy.
+	(parser_common_init): New function, shared by parse and parse_once.
+	Initializes embedded scanner.
+	(parser_cleanup): New function, shared by parse_once and
+	parser_destroy.
+	(parser): Use parser_common_init.
+
+	* parser.h (parser_t): New member, yyscan.
+	(reset_scanner, parser_common_init): Declared.
+
+	* parser.l (reset_scanner): New function.
+
+	* parser.y (parse_once): Use parser_common_init, and
+	thus perform only a few initializations. Do not
+	define scanner as a local variable.
+	(parse): Call reset_scanner instead of
+	yylex_init since the scanner is being reused,
+	and for the same reason do not call yylex_destroy.
+	GC will do that now.
+
 2015-07-08  Kaz Kylheku  <kaz@kylheku.com>
 
 	Bugfix: define-modify-macro not registered for auto-loading.
diff --git a/parser.c b/parser.c
index c0f3c6da..aa85a7f4 100644
--- a/parser.c
+++ b/parser.c
@@ -64,32 +64,52 @@ static void parser_mark(val obj)
   gc_mark(p->primer);
 }
 
+static void parser_destroy(val obj)
+{
+  parser_t *p = coerce(parser_t *, obj->co.handle);
+  parser_cleanup(p);
+}
+
 static struct cobj_ops parser_ops = {
   eq,
   cobj_print_op,
-  cobj_destroy_free_op,
+  parser_destroy,
   parser_mark,
   cobj_hash_op,
 };
 
-val parser(val stream, val lineno, val primer)
+void parser_common_init(parser_t *p)
 {
-  parser_t *p = coerce(parser_t *, chk_malloc(sizeof *p));
-  val parser;
   p->parser = nil;
-  p->lineno = 0;
+  p->lineno = 1;
   p->errors = 0;
   p->stream = nil;
   p->name = nil;
   p->prepared_msg = nil;
   p->syntax_tree = nil;
   p->primer = nil;
-  p->scanner = 0;
+  yylex_init(&p->yyscan);
+  p->scanner = convert(scanner_t *, p->yyscan);
+  yyset_extra(p, p->scanner);
+}
+
+void parser_cleanup(parser_t *p)
+{
+  if (p->scanner != 0)
+    yylex_destroy(p->scanner);
+}
+
+val parser(val stream, val lineno, val primer)
+{
+  parser_t *p = coerce(parser_t *, chk_malloc(sizeof *p));
+  val parser;
+  parser_common_init(p);
   parser = cobj(coerce(mem_t *, p), parser_s, &parser_ops);
   p->parser = parser;
   p->lineno = c_num(default_arg(lineno, one));
   p->stream = stream;
   p->primer = primer;
+
   return parser;
 }
 
diff --git a/parser.h b/parser.h
index e6f531f2..0db10d4e 100644
--- a/parser.h
+++ b/parser.h
@@ -26,6 +26,11 @@
 
 typedef struct yyguts_t scanner_t;
 
+#ifndef YY_TYPEDEF_YY_SCANNER_T
+#define YY_TYPEDEF_YY_SCANNER_T
+typedef void *yyscan_t;
+#endif
+
 typedef struct {
   val parser;
   cnum lineno;
@@ -35,14 +40,10 @@ typedef struct {
   val prepared_msg;
   val syntax_tree;
   val primer;
+  yyscan_t yyscan;
   scanner_t *scanner;
 } parser_t;
 
-#ifndef YY_TYPEDEF_YY_SCANNER_T
-#define YY_TYPEDEF_YY_SCANNER_T
-typedef void *yyscan_t;
-#endif
-
 extern const wchar_t *spec_file;
 extern val form_to_ln_hash;
 extern val parser_s;
@@ -52,6 +53,7 @@ void yyerrorf(scanner_t *scanner, val s, ...);
 void yybadtoken(parser_t *, int tok, val context);
 void end_of_regex(scanner_t *scanner);
 void end_of_char(scanner_t *scanner);
+void reset_scanner(scanner_t *scanner);
 int yylex_init(yyscan_t *pscanner);
 int yylex_destroy(yyscan_t scanner);
 parser_t *yyget_extra(yyscan_t scanner);
@@ -72,6 +74,8 @@ val rlcp_tree(val to, val from);
 val regex_parse(val string, val error_stream);
 val lisp_parse(val source, val error_stream, val error_return_val, val name);
 val read_eval_stream(val stream, val error_stream, val hash_bang_support);
+void parser_common_init(parser_t *);
+void parser_cleanup(parser_t *);
 val parser(val stream, val lineno, val primer);
 val get_parser(val stream);
 val parser_errors(val parser);
diff --git a/parser.l b/parser.l
index f7c717e8..4739dd59 100644
--- a/parser.l
+++ b/parser.l
@@ -960,6 +960,14 @@ void end_of_char(scanner_t *yyg)
   yy_pop_state(yyg);
 }
 
+void reset_scanner(scanner_t *yyg)
+{
+  while (YYSTATE != INITIAL)
+    yy_pop_state(yyg);
+
+  yy_flush_buffer(YY_CURRENT_BUFFER, yyg);
+}
+
 val source_loc(val form)
 {
   return gethash(form_to_ln_hash, form);
diff --git a/parser.y b/parser.y
index 12324f51..de3f600d 100644
--- a/parser.y
+++ b/parser.y
@@ -1443,22 +1443,15 @@ void yybadtoken(parser_t *parser, int tok, val context)
 int parse_once(val stream, val name, parser_t *parser)
 {
   int res;
-  yyscan_t scanner;
 
-  parser->lineno = 1;
-  parser->errors = 0;
+  parser_common_init(parser);
+
   parser->stream = stream;
   parser->name = name;
-  parser->prepared_msg = nil;
-  parser->syntax_tree = nil;
-  yylex_init(&scanner);
-  parser->scanner = convert(scanner_t *, scanner);
-
-  yyset_extra(parser, parser->scanner);
 
   res = yyparse(parser->scanner, parser);
 
-  yylex_destroy(parser->scanner);
+  parser_cleanup(parser);
 
   return res;
 }
@@ -1466,20 +1459,14 @@ int parse_once(val stream, val name, parser_t *parser)
 int parse(parser_t *parser)
 {
   int res;
-  yyscan_t scanner;
 
   parser->errors = 0;
   parser->prepared_msg = nil;
   parser->syntax_tree = nil;
   prime_parser(parser->parser);
-  yylex_init(&scanner);
-  parser->scanner = convert(scanner_t *, scanner);
-
-  yyset_extra(parser, parser->scanner);
+  reset_scanner(parser->scanner);
 
   res = yyparse(parser->scanner, parser);
 
-  yylex_destroy(parser->scanner);
-
   return res;
 }