Big switch to reentrant lexing and parsing.

* parser.l (YY_INPUT): Stop relying on removed yyin_stream;
refer to stream via yyextra.
(yyin_stream, lineno, errors, spec_file_str,
prepared_error_message): Global variables removed.
(yyget_column, yyset_column): Missing prototypes not generated by flex
in bison bridge mode have to be added by us to avoid
warning.
(yyerror): Takes parser and scanner as parameters.  Prepared error
message is now in the parser context.  Calls to other error handling
functions receive scanner context.
(yyerr): New function.
(yyerrorf, yyerrprepf): Takes scanner argument, chases extra data to
get to parser, and refers to parser variables instead of globals.
(num_esc): Scanner argument added.
(%option reentrant, %option bison-bridge, %option extra-type): New
flex options.
(grammar): yyscanner added everywhere.
(end_of_char): Takes scanner argument.
(parse_init): Removed references to yyin_stream and
prepared_error_message.
(parse_reset): Function renamed to open_txr_file. Returns
results via pointers instead of setting global variables.
(regex_parse, lisp_parse): Use reentrant parser interface.

* parser.y (yyerror): Prototype removed.
(yylex): Prototype moved after grammar, with new arguments.
(sym_helper, define_transform): Take scanner argument.
(make_expr): Takes parser argument.
(rlrec): New static function.
(rl): Function turned into macro.
(mkexp, symhlpr): New macros.
(%purse-parser, %parse-param, %lex-param): New Yacc options.
(grammar): Actions re-worked for reentrance. Parser and scanner
contexts are passed down to helper functions, in some cases
via the three new macros. The result of the parse is stored
in the syntax_tree member of the parser_t structure instead
of a global. The yylex function receives the scanner instance.
(get_spec): Function removed.
(parse): New function.

* parser.h (lineno, errors, yyin_stream, spec_file_str):
Declarations removed.
(parser_t): New struct.
(yyerr): New function declared.
(yyparse, yyerror, yyerrorf, end_of_regex, end_of_char,
yylex, yylex_destroy): Declarations updated.

1 files changed, 10 insertions, 13 deletions

diff --git a/txr.c b/txr.c
index 02d42048..d637ddbb 100644
--- a/txr.c
+++ b/txr.c
@@ -301,17 +301,14 @@ int txr_main(int argc, char **argv)
   val spec_file = nil;
   val bindings = nil;
   val evaled = nil;
+  val spec_file_str;
   int match_loglevel = opt_loglevel;
   val arg_undo = nil, arg;
+  val parse_stream = std_input;
   list_collect_decl(arg_list, arg_tail);
 
-  prot1(&spec_file_str);
-
   setvbuf(stderr, 0, _IOLBF, 0);
 
-
-  yyin_stream = std_input;
-
   if (argc <= 1) {
     hint();
     return EXIT_FAILURE;
@@ -519,7 +516,7 @@ int txr_main(int argc, char **argv)
     if (gt(length_str(specstring), zero) &&
         chr_str(specstring, minus(length_str(specstring), one)) != chr('\n'))
       specstring = cat_str(list(specstring, string(L"\n"), nao), nil);
-    yyin_stream = make_string_byte_input_stream(specstring);
+    parse_stream = make_string_byte_input_stream(specstring);
     if (arg)
       arg_list = arg_undo;
   } else if (spec_file) {
@@ -527,7 +524,7 @@ int txr_main(int argc, char **argv)
       FILE *in = w_fopen(c_str(spec_file), L"r");
       if (in == 0)
         uw_throwf(file_error_s, lit("unable to open ~a"), spec_file, nao);
-      yyin_stream = make_stdio_stream(in, spec_file);
+      parse_stream = make_stdio_stream(in, spec_file);
       spec_file_str = spec_file;
     } else {
       spec_file_str = lit("stdin");
@@ -546,7 +543,7 @@ int txr_main(int argc, char **argv)
       FILE *in = w_fopen(c_str(arg), L"r");
       if (in == 0)
         uw_throwf(file_error_s, lit("unable to open ~a"), arg, nao);
-      yyin_stream = make_stdio_stream(in, arg);
+      parse_stream = make_stdio_stream(in, arg);
       spec_file_str = arg;
     } else {
       spec_file_str = lit("stdin");
@@ -557,14 +554,14 @@ int txr_main(int argc, char **argv)
 
   {
     int gc = gc_state(0);
-    yyparse();
-    yylex_destroy();
+    parser_t parser;
+    parse(parse_stream, spec_file_str, &parser);
     gc_state(gc);
 
-    if (errors)
+    if (parser.errors)
       return EXIT_FAILURE;
 
-    spec = remove_hash_bang_line(get_spec());
+    spec = remove_hash_bang_line(parser.syntax_tree);
 
     opt_loglevel = match_loglevel;
 
@@ -577,7 +574,7 @@ int txr_main(int argc, char **argv)
 
     {
       int retval = extract(spec, arg_list, bindings);
-      return errors ? EXIT_FAILURE : retval;
+      return parser.errors ? EXIT_FAILURE : retval;
     }
   }
 }