Use new pushback token priming for single regex parse.

* parser.h (enum prime_parser): New enum.
(prime_parser, prime_scanner, parse): Declarations updated with new
argument.

* parser.c (prime_parser): New argument of enum prime_parser type
Select appropriate secret token for regex and Lisp case.  Pass prime
selector down to prime_scanner.
(regex_parse): Do not prepend secret escape to string.  Do not use
parse_once function; instead do the parser init and cleanup here and
use the parse function.
(lisp_parse): Pass new argument to parse, configuring the parser to be
primed for Lisp parsing.

* parser.l (grammar): Rule producing SECRET_ESCAPE_R removed.
(prime_scanner): New argument. Pop the scanner state down to INITIAL.
Then unconditionally switch to appopriate state based on priming
configuration.

* parser.y (parse): New argument for priming selection, passed down to
prime parser.

1 files changed, 10 insertions, 7 deletions

diff --git a/parser.l b/parser.l
index 92bad198..2610a921 100644
--- a/parser.l
+++ b/parser.l
@@ -858,11 +858,6 @@ UONLY   {U2}{U}|{U3}{U}{U}|{U4}{U}{U}{U}
   yy_push_state(SPECIAL, yyscanner);
 }
 
-<INITIAL>@\x01R {
-  yy_push_state(REGEX, yyscanner);
-  return SECRET_ESCAPE_R;
-}
-
 <INITIAL>^@[#;].*\n {
   /* eat whole line comment */
   yyextra->lineno++;
@@ -1043,12 +1038,20 @@ int yylex(YYSTYPE *yylval_param, yyscan_t yyscanner)
   return yy_char;
 }
 
-void prime_scanner(scanner_t *yyg)
+void prime_scanner(scanner_t *yyg, enum prime_parser prim)
 {
-  if (YYSTATE == INITIAL) {
+  while (YYSTATE != INITIAL)
+    yy_pop_state(yyg);
+
+  switch (prim) {
+  case prime_lisp:
     yy_push_state(SPECIAL, yyg);
     yy_push_state(NESTED, yyg);
     yy_push_state(NESTED, yyg);
+    break;
+  case prime_regex:
+    yy_push_state(REGEX, yyg);
+    break;
   }
 }