doc: one of the fixes for an ambiguous grammar was ambiguous too

[bison.git] / src / scan-gram.l

diff --git a/src/scan-gram.l b/src/scan-gram.l
index a22cafdcd8cf64247ee925ce207490037659c88c..ad061cc6f86159ba93da4023e60fa326111f8b86 100644 (file)
--- a/src/scan-gram.l
+++ b/src/scan-gram.l
@@ -1,7 +1,6 @@
 /* Bison Grammar Scanner                             -*- C -*-
 
 /* Bison Grammar Scanner                             -*- C -*-
 

-   Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free
-   Software Foundation, Inc.
+   Copyright (C) 2002-2012 Free Software Foundation, Inc.

 
    This file is part of Bison, the GNU Compiler Compiler.
 
 
    This file is part of Bison, the GNU Compiler Compiler.
 


@@ -18,7 +17,7 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 

-%option debug nodefault nounput noyywrap never-interactive
+%option debug nodefault noinput nounput noyywrap never-interactive

 %option prefix="gram_" outfile="lex.yy.c"
 
 %{
 %option prefix="gram_" outfile="lex.yy.c"
 
 %{


@@ -37,6 +36,7 @@
 #include "reader.h"
 #include "uniqstr.h"
 
 #include "reader.h"
 #include "uniqstr.h"
 

+#include <c-ctype.h>

 #include <mbswidth.h>
 #include <quote.h>
 
 #include <mbswidth.h>
 #include <quote.h>
 


@@ -55,9 +55,21 @@ static boundary scanner_cursor;
 static size_t no_cr_read (FILE *, char *, size_t);
 #define YY_INPUT(buf, result, size) ((result) = no_cr_read (yyin, buf, size))
 
 static size_t no_cr_read (FILE *, char *, size_t);
 #define YY_INPUT(buf, result, size) ((result) = no_cr_read (yyin, buf, size))
 

+#define ROLLBACK_CURRENT_TOKEN                                  \
+  do {                                                          \
+    scanner_cursor.column -= mbsnwidth (yytext, yyleng, 0);    \
+    yyless (0);                                                 \
+  } while (0)
+

 /* A string representing the most recently saved token.  */
 static char *last_string;
 
 /* A string representing the most recently saved token.  */
 static char *last_string;
 

+/* Bracketed identifier. */
+static uniqstr bracketed_id_str = 0;
+static location bracketed_id_loc;
+static boundary bracketed_id_start;
+static int bracketed_id_context_state = 0;
+

 void
 gram_scanner_last_string_free (void)
 {
 void
 gram_scanner_last_string_free (void)
 {


@@ -76,11 +88,11 @@ static void unexpected_newline (boundary, char const *);
  /* Strings and characters in directives/rules. */
 %x SC_ESCAPED_STRING SC_ESCAPED_CHARACTER
  /* A identifier was just read in directives/rules.  Special state
  /* Strings and characters in directives/rules. */
 %x SC_ESCAPED_STRING SC_ESCAPED_CHARACTER
  /* A identifier was just read in directives/rules.  Special state

-    to capture the sequence `identifier :'. */
+    to capture the sequence 'identifier :'. */

 %x SC_AFTER_IDENTIFIER
 
  /* Three types of user code:
 %x SC_AFTER_IDENTIFIER
 
  /* Three types of user code:

-    - prologue (code between `%{' `%}' in the first section, before %%);
+    - prologue (code between '%{' '%}' in the first section, before %%);

     - actions, printers, union, etc, (between braced in the middle section);
     - epilogue (everything after the second %%). */
 %x SC_PROLOGUE SC_BRACED_CODE SC_EPILOGUE
     - actions, printers, union, etc, (between braced in the middle section);
     - epilogue (everything after the second %%). */
 %x SC_PROLOGUE SC_BRACED_CODE SC_EPILOGUE


@@ -88,9 +100,11 @@ static void unexpected_newline (boundary, char const *);
 %x SC_COMMENT SC_LINE_COMMENT
  /* Strings and characters in code. */
 %x SC_STRING SC_CHARACTER
 %x SC_COMMENT SC_LINE_COMMENT
  /* Strings and characters in code. */
 %x SC_STRING SC_CHARACTER

+ /* Bracketed identifiers support. */
+%x SC_BRACKETED_ID SC_RETURN_BRACKETED_ID

 
 

-letter   [-.abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_]
-id       {letter}({letter}|[0-9])*
+letter   [.abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_]
+id       {letter}({letter}|[-0-9])*

 directive %{id}
 int      [0-9]+
 
 directive %{id}
 int      [0-9]+
 


@@ -106,13 +120,13 @@ splice     (\\[ \f\t\v]*\n)*
 %%
 %{
   /* Nesting level of the current code in braces.  */
 %%
 %{
   /* Nesting level of the current code in braces.  */

-  int braces_level IF_LINT (= 0);
+  int braces_level PACIFY_CC (= 0);

 
   /* Parent context state, when applicable.  */
 
   /* Parent context state, when applicable.  */

-  int context_state IF_LINT (= 0);
+  int context_state PACIFY_CC (= 0);

 
   /* Location of most recent identifier, when applicable.  */
 
   /* Location of most recent identifier, when applicable.  */

-  location id_loc IF_LINT (= empty_location);
+  location id_loc PACIFY_CC (= empty_location);

 
   /* Where containing code started, when applicable.  Its initial
      value is relevant only when yylex is invoked in the SC_EPILOGUE
 
   /* Where containing code started, when applicable.  Its initial
      value is relevant only when yylex is invoked in the SC_EPILOGUE


@@ -121,7 +135,7 @@ splice       (\\[ \f\t\v]*\n)*
 
   /* Where containing comment or string or character literal started,
      when applicable.  */
 
   /* Where containing comment or string or character literal started,
      when applicable.  */

-  boundary token_start IF_LINT (= scanner_cursor);
+  boundary token_start PACIFY_CC (= scanner_cursor);

 %}
 
 
 %}
 
 


@@ -129,10 +143,10 @@ splice     (\\[ \f\t\v]*\n)*
   | Scanning white space.  |
   `-----------------------*/
 
   | Scanning white space.  |
   `-----------------------*/
 

-<INITIAL,SC_AFTER_IDENTIFIER>
+<INITIAL,SC_AFTER_IDENTIFIER,SC_BRACKETED_ID,SC_RETURN_BRACKETED_ID>

 {
   /* Comments and white space.  */
 {
   /* Comments and white space.  */

-  ","         warn_at (*loc, _("stray `,' treated as white space"));
+  ","          warn_at (*loc, _("stray ',' treated as white space"));

   [ \f\n\t\v]  |
   "//".*       ;
   "/*" {
   [ \f\n\t\v]  |
   "//".*       ;
   "/*" {


@@ -208,12 +222,6 @@ splice      (\\[ \f\t\v]*\n)*
     complain_at (*loc, _("invalid directive: %s"), quote (yytext));
   }
 
     complain_at (*loc, _("invalid directive: %s"), quote (yytext));
   }
 

-  /* Identifiers may not start with a digit.  Yet, don't silently
-     accept "1FOO" as "1 FOO".  */
-  {int}{id} {
-    complain_at (*loc, _("invalid identifier: %s"), quote (yytext));
-  }
-

   "="                     return EQUAL;
   "|"                     return PIPE;
   ";"                     return SEMICOLON;
   "="                     return EQUAL;
   "|"                     return PIPE;
   ";"                     return SEMICOLON;


@@ -223,6 +231,7 @@ splice       (\\[ \f\t\v]*\n)*
   {id} {
     val->uniqstr = uniqstr_new (yytext);
     id_loc = *loc;
   {id} {
     val->uniqstr = uniqstr_new (yytext);
     id_loc = *loc;

+    bracketed_id_str = NULL;

     BEGIN SC_AFTER_IDENTIFIER;
   }
 
     BEGIN SC_AFTER_IDENTIFIER;
   }
 


@@ -235,8 +244,14 @@ splice      (\\[ \f\t\v]*\n)*
     return INT;
   }
 
     return INT;
   }
 

-  /* Characters.  We don't check there is only one.  */
-  "'"        STRING_GROW; token_start = loc->start; BEGIN SC_ESCAPED_CHARACTER;
+  /* Identifiers may not start with a digit.  Yet, don't silently
+     accept "1FOO" as "1 FOO".  */
+  {int}{id} {
+    complain_at (*loc, _("invalid identifier: %s"), quote (yytext));
+  }
+
+  /* Characters.  */
+  "'"        token_start = loc->start; BEGIN SC_ESCAPED_CHARACTER;

 
   /* Strings. */
   "\""       token_start = loc->start; BEGIN SC_ESCAPED_STRING;
 
   /* Strings. */
   "\""       token_start = loc->start; BEGIN SC_ESCAPED_STRING;


@@ -268,8 +283,15 @@ splice      (\\[ \f\t\v]*\n)*
     return PERCENT_PERCENT;
   }
 
     return PERCENT_PERCENT;
   }
 

+  "[" {
+    bracketed_id_str = NULL;
+    bracketed_id_start = loc->start;
+    bracketed_id_context_state = YY_START;
+    BEGIN SC_BRACKETED_ID;
+  }
+

   . {
   . {

-    complain_at (*loc, _("invalid character: %s"), quote (yytext));
+    complain_at (*loc, _("invalid character: %s"), quote_mem (yytext, yyleng));

   }
 
   <<EOF>> {
   }
 
   <<EOF>> {


@@ -285,28 +307,97 @@ splice     (\\[ \f\t\v]*\n)*
 
 <SC_AFTER_IDENTIFIER>
 {
 
 <SC_AFTER_IDENTIFIER>
 {

+  "[" {
+    if (bracketed_id_str)
+      {
+       ROLLBACK_CURRENT_TOKEN;
+       BEGIN SC_RETURN_BRACKETED_ID;
+       *loc = id_loc;
+       return ID;
+      }
+    else
+      {
+       bracketed_id_start = loc->start;
+       bracketed_id_context_state = YY_START;
+       BEGIN SC_BRACKETED_ID;
+      }
+  }

   ":" {
   ":" {

+    BEGIN (bracketed_id_str ? SC_RETURN_BRACKETED_ID : INITIAL);

     *loc = id_loc;
     *loc = id_loc;

-    BEGIN INITIAL;

     return ID_COLON;
   }
   . {
     return ID_COLON;
   }
   . {

-    scanner_cursor.column -= mbsnwidth (yytext, yyleng, 0);
-    yyless (0);
+    ROLLBACK_CURRENT_TOKEN;
+    BEGIN (bracketed_id_str ? SC_RETURN_BRACKETED_ID : INITIAL);

     *loc = id_loc;
     *loc = id_loc;

-    BEGIN INITIAL;

     return ID;
   }
   <<EOF>> {
     return ID;
   }
   <<EOF>> {

+    BEGIN (bracketed_id_str ? SC_RETURN_BRACKETED_ID : INITIAL);

     *loc = id_loc;
     *loc = id_loc;

-    BEGIN INITIAL;

     return ID;
   }
 }
 
     return ID;
   }
 }
 

+  /*--------------------------------.
+  | Scanning bracketed identifiers. |
+  `--------------------------------*/
+
+<SC_BRACKETED_ID>
+{
+  {id} {
+    if (bracketed_id_str)
+      {
+       complain_at (*loc, _("unexpected identifier in bracketed name: %s"),
+                    quote (yytext));
+      }
+    else
+      {
+       bracketed_id_str = uniqstr_new (yytext);
+       bracketed_id_loc = *loc;
+      }
+  }
+  "]" {
+    BEGIN bracketed_id_context_state;
+    if (bracketed_id_str)
+      {
+       if (INITIAL == bracketed_id_context_state)
+         {
+           val->uniqstr = bracketed_id_str;
+           bracketed_id_str = 0;
+           *loc = bracketed_id_loc;
+           return BRACKETED_ID;
+         }
+      }
+    else
+      complain_at (*loc, _("an identifier expected"));
+  }
+  . {
+    complain_at (*loc, _("invalid character in bracketed name: %s"),
+                quote_mem (yytext, yyleng));
+  }
+  <<EOF>> {
+    BEGIN bracketed_id_context_state;
+    unexpected_eof (bracketed_id_start, "]");
+  }
+}
+
+<SC_RETURN_BRACKETED_ID>
+{
+  . {
+    ROLLBACK_CURRENT_TOKEN;
+    val->uniqstr = bracketed_id_str;
+    bracketed_id_str = 0;
+    *loc = bracketed_id_loc;
+    BEGIN INITIAL;
+    return BRACKETED_ID;
+  }
+}
+

 
   /*---------------------------------------------------------------.
 
   /*---------------------------------------------------------------.

-  | Scanning a Yacc comment.  The initial `/ *' is already eaten.  |
+  | Scanning a Yacc comment.  The initial '/ *' is already eaten.  |

   `---------------------------------------------------------------*/
 
 <SC_YACC_COMMENT>
   `---------------------------------------------------------------*/
 
 <SC_YACC_COMMENT>


@@ -318,7 +409,7 @@ splice       (\\[ \f\t\v]*\n)*
 
 
   /*------------------------------------------------------------.
 
 
   /*------------------------------------------------------------.

-  | Scanning a C comment.  The initial `/ *' is already eaten.  |
+  | Scanning a C comment.  The initial '/ *' is already eaten.  |

   `------------------------------------------------------------*/
 
 <SC_COMMENT>
   `------------------------------------------------------------*/
 
 <SC_COMMENT>


@@ -329,7 +420,7 @@ splice       (\\[ \f\t\v]*\n)*
 
 
   /*--------------------------------------------------------------.
 
 
   /*--------------------------------------------------------------.

-  | Scanning a line comment.  The initial `//' is already eaten.  |
+  | Scanning a line comment.  The initial '//' is already eaten.  |

   `--------------------------------------------------------------*/
 
 <SC_LINE_COMMENT>
   `--------------------------------------------------------------*/
 
 <SC_LINE_COMMENT>


@@ -374,24 +465,42 @@ splice     (\\[ \f\t\v]*\n)*
 <SC_ESCAPED_CHARACTER>
 {
   "'"|"\n" {
 <SC_ESCAPED_CHARACTER>
 {
   "'"|"\n" {

-    if (yytext[0] == '\n')
-      unexpected_newline (token_start, "'");
-    STRING_GROW;

     STRING_FINISH;
     loc->start = token_start;
     STRING_FINISH;
     loc->start = token_start;

-    val->character = last_string[1];
+    val->character = last_string[0];
+    {
+      /* FIXME: Eventually, make these errors.  */
+      if (last_string[0] == '\0')
+        {
+          warn_at (*loc, _("empty character literal"));
+          /* '\0' seems dangerous even if we are about to complain.  */
+          val->character = '\'';
+        }
+      else if (last_string[1] != '\0')
+        warn_at (*loc, _("extra characters in character literal"));
+    }
+    if (yytext[0] == '\n')
+      unexpected_newline (token_start, "'");

     STRING_FREE;
     BEGIN INITIAL;
     return CHAR;
   }
   <<EOF>> {
     STRING_FREE;
     BEGIN INITIAL;
     return CHAR;
   }
   <<EOF>> {

-    unexpected_eof (token_start, "'");

     STRING_FINISH;
     loc->start = token_start;
     STRING_FINISH;
     loc->start = token_start;

-    if (strlen (last_string) > 1)
-      val->character = last_string[1];
-    else
-      val->character = last_string[0];
+    val->character = last_string[0];
+    {
+      /* FIXME: Eventually, make these errors.  */
+      if (last_string[0] == '\0')
+        {
+          warn_at (*loc, _("empty character literal"));
+          /* '\0' seems dangerous even if we are about to complain.  */
+          val->character = '\'';
+        }
+      else if (last_string[1] != '\0')
+        warn_at (*loc, _("extra characters in character literal"));
+    }
+    unexpected_eof (token_start, "'");

     STRING_FREE;
     BEGIN INITIAL;
     return CHAR;
     STRING_FREE;
     BEGIN INITIAL;
     return CHAR;


@@ -412,10 +521,9 @@ splice      (\\[ \f\t\v]*\n)*
 {
   \\[0-7]{1,3} {
     unsigned long int c = strtoul (yytext + 1, NULL, 8);
 {
   \\[0-7]{1,3} {
     unsigned long int c = strtoul (yytext + 1, NULL, 8);

-    if (UCHAR_MAX < c)
-      complain_at (*loc, _("invalid escape sequence: %s"), quote (yytext));
-    else if (! c)
-      complain_at (*loc, _("invalid null character: %s"), quote (yytext));
+    if (!c || UCHAR_MAX < c)
+      complain_at (*loc, _("invalid number after \\-escape: %s"),
+                   yytext+1);

     else
       obstack_1grow (&obstack_for_string, c);
   }
     else
       obstack_1grow (&obstack_for_string, c);
   }


@@ -423,10 +531,9 @@ splice      (\\[ \f\t\v]*\n)*
   \\x[0-9abcdefABCDEF]+ {
     verify (UCHAR_MAX < ULONG_MAX);
     unsigned long int c = strtoul (yytext + 2, NULL, 16);
   \\x[0-9abcdefABCDEF]+ {
     verify (UCHAR_MAX < ULONG_MAX);
     unsigned long int c = strtoul (yytext + 2, NULL, 16);

-    if (UCHAR_MAX < c)
-      complain_at (*loc, _("invalid escape sequence: %s"), quote (yytext));
-    else if (! c)
-      complain_at (*loc, _("invalid null character: %s"), quote (yytext));
+    if (!c || UCHAR_MAX < c)
+      complain_at (*loc, _("invalid number after \\-escape: %s"),
+                   yytext+1);

     else
       obstack_1grow (&obstack_for_string, c);
   }
     else
       obstack_1grow (&obstack_for_string, c);
   }


@@ -444,16 +551,20 @@ splice     (\\[ \f\t\v]*\n)*
 
   \\(u|U[0-9abcdefABCDEF]{4})[0-9abcdefABCDEF]{4} {
     int c = convert_ucn_to_byte (yytext);
 
   \\(u|U[0-9abcdefABCDEF]{4})[0-9abcdefABCDEF]{4} {
     int c = convert_ucn_to_byte (yytext);

-    if (c < 0)
-      complain_at (*loc, _("invalid escape sequence: %s"), quote (yytext));
-    else if (! c)
-      complain_at (*loc, _("invalid null character: %s"), quote (yytext));
+    if (c <= 0)
+      complain_at (*loc, _("invalid number after \\-escape: %s"),
+                   yytext+1);

     else
       obstack_1grow (&obstack_for_string, c);
   }
   \\(.|\n)     {
     else
       obstack_1grow (&obstack_for_string, c);
   }
   \\(.|\n)     {

-    complain_at (*loc, _("unrecognized escape sequence: %s"), quote (yytext));
-    STRING_GROW;
+    char const *p = yytext + 1;
+    /* Quote only if escaping won't make the character visible.  */
+    if (c_isspace ((unsigned char) *p) && c_isprint ((unsigned char) *p))
+      p = quote (p);
+    else
+      p = quotearg_style_mem (escape_quoting_style, p, 1);
+    complain_at (*loc, _("invalid character after \\-escape: %s"), p);

   }
 }
 
   }
 }
 


@@ -537,8 +648,8 @@ splice       (\\[ \f\t\v]*\n)*
       }
   }
 
       }
   }
 

-  /* Tokenize `<<%' correctly (as `<<' `%') rather than incorrrectly
-     (as `<' `<%').  */
+  /* Tokenize '<<%' correctly (as '<<' '%') rather than incorrrectly
+     (as '<' '<%').  */

   "<"{splice}"<"  STRING_GROW;
 
   <<EOF>> {
   "<"{splice}"<"  STRING_GROW;
 
   <<EOF>> {


@@ -729,7 +840,7 @@ convert_ucn_to_byte (char const *ucn)
 
 
 /*----------------------------------------------------------------.
 
 
 /*----------------------------------------------------------------.

-| Handle `#line INT "FILE"'.  ARGS has already skipped `#line '.  |
+| Handle '#line INT "FILE"'.  ARGS has already skipped '#line '.  |

 `----------------------------------------------------------------*/
 
 static void
 `----------------------------------------------------------------*/
 
 static void


@@ -737,8 +848,8 @@ handle_syncline (char *args, location loc)
 {
   char *after_num;
   unsigned long int lineno = strtoul (args, &after_num, 10);
 {
   char *after_num;
   unsigned long int lineno = strtoul (args, &after_num, 10);

-  char *file = strchr (after_num, '"') + 1;
-  *strchr (file, '"') = '\0';
+  char *file = mbschr (after_num, '"') + 1;
+  *mbschr (file, '"') = '\0';

   if (INT_MAX <= lineno)
     {
       warn_at (loc, _("line number overflow"));
   if (INT_MAX <= lineno)
     {
       warn_at (loc, _("line number overflow"));


@@ -761,6 +872,10 @@ unexpected_end (boundary start, char const *msgid, char const *token_end)
   location loc;
   loc.start = start;
   loc.end = scanner_cursor;
   location loc;
   loc.start = start;
   loc.end = scanner_cursor;

+  token_end = quote (token_end);
+  // Instead of '\'', display "'".
+  if (!strcmp (token_end, "'\\''"))
+    token_end = "\"'\"";

   complain_at (loc, _(msgid), token_end);
 }
 
   complain_at (loc, _(msgid), token_end);
 }
 


@@ -773,7 +888,7 @@ unexpected_end (boundary start, char const *msgid, char const *token_end)
 static void
 unexpected_eof (boundary start, char const *token_end)
 {
 static void
 unexpected_eof (boundary start, char const *token_end)
 {

-  unexpected_end (start, N_("missing `%s' at end of file"), token_end);
+  unexpected_end (start, N_("missing %s at end of file"), token_end);

 }
 
 
 }
 
 


@@ -784,7 +899,7 @@ unexpected_eof (boundary start, char const *token_end)
 static void
 unexpected_newline (boundary start, char const *token_end)
 {
 static void
 unexpected_newline (boundary start, char const *token_end)
 {

-  unexpected_end (start, N_("missing `%s' at end of line"), token_end);
+  unexpected_end (start, N_("missing %s at end of line"), token_end);

 }
 
 
 }