variables: accept dashes.

* data/bison.m4 (b4_percent_define_if_define_): Also map dashes to
	underscores.
	* src/scan-gram.l ({id}): Also accept dashes after the initial
	letter.
	({directive}): Use {id}.
	* src/parse-gram.y: Comment and formatting changes.
	* doc/bison.texinfo (Symbols): Adjust the lexical definitions of
	symbols.
	* src/complain.h, src/complain.c (yacc_at): New.
	* src/symtab.c (symbol_new): Use yacc_at to report inappropriate
	symbol names.
	* src/output.c (token_definitions_output): Do not #define token
	names with dashes.

ChangeLog

@@ -1,3 +1,20 @@
+2009-04-20  Akim Demaille  <demaille@gostai.com>
+
+	variables: accept dashes.
+	* data/bison.m4 (b4_percent_define_if_define_): Also map dashes to
+	underscores.
+	* src/scan-gram.l ({id}): Also accept dashes after the initial
+	letter.
+	({directive}): Use {id}.
+	* src/parse-gram.y: Comment and formatting changes.
+	* doc/bison.texinfo (Symbols): Adjust the lexical definitions of
+	symbols.
+	* src/complain.h, src/complain.c (yacc_at): New.
+	* src/symtab.c (symbol_new): Use yacc_at to report inappropriate
+	symbol names.
+	* src/output.c (token_definitions_output): Do not #define token
+	names with dashes.
+
 2009-04-20  Akim Demaille  <demaille@gostai.com>
 
 	Consistently refer to Yacc, not YACC.

data/bison.m4

@@ -668,9 +668,10 @@ m4_define([b4_percent_define_default],
 # b4_percent_define_if_define(VARIABLE)
 # -------------------------------------
 # Define b4_VARIABLE_if that executes its $1 or $2 depending whether
-# VARIABLE was %defined.  The character `.' in VARIABLE is mapped to `_'.
+# VARIABLE was %defined.  The characters `.' and `-' in VARIABLE are mapped
+# to `_'.
 m4_define([b4_percent_define_if_define_],
-[m4_define(m4_bpatsubst([b4_$1_if], [[.]], [_]),
+[m4_define(m4_bpatsubst([b4_$1_if], [[-.]], [_]),
            [b4_percent_define_flag_if([$1], [$2], [$3])])])
 m4_define([b4_percent_define_if_define],
 [b4_percent_define_default([[$1]], [[false]])

doc/bison.texinfo

@@ -3053,8 +3053,12 @@ A @dfn{nonterminal symbol} stands for a class of syntactically
 equivalent groupings.  The symbol name is used in writing grammar rules.
 By convention, it should be all lower case.
 
-Symbol names can contain letters, digits (not at the beginning),
+Symbol names can contain letters, underscores, period, and (not at the
-underscores and periods.  Periods make sense only in nonterminals.
+beginning) digits and dashes.  Dashes in symbol names are a GNU
+extension, incompatible with @acronym{POSIX} Yacc.  Terminal symbols
+that contain periods or dashes make little sense: since they are not
+valid symbols (in most programming languages) they are not exported as
+token names.
 
 There are three ways of writing terminal symbols in the grammar:
 

src/complain.c

@@ -1,6 +1,6 @@
 /* Declaration for error-reporting function for Bison.
 
-   Copyright (C) 2000, 2001, 2002, 2004, 2005, 2006
+   Copyright (C) 2000, 2001, 2002, 2004, 2005, 2006, 2009
    Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
@@ -120,6 +120,27 @@ complain (const char *message, ...)
 }
 
 
+/*--------------------------------------------------------------.
+| An incompatibility with POSIX Yacc: mapped either to warn* or |
+| complain* depending on yacc_flag.                             |
+`--------------------------------------------------------------*/
+
+void
+yacc_at (location loc, const char *message, ...)
+{
+  if (yacc_flag)
+    {
+      ERROR_MESSAGE (&loc, NULL, message);
+      complaint_issued = true;
+    }
+  else if (warnings_flag & warnings_yacc)
+    {
+      set_warning_issued ();
+      ERROR_MESSAGE (&loc, _("warning"), message);
+    }
+}
+
+
 /*-------------------------------------------------.
 | A severe error has occurred, we cannot proceed.  |
 `-------------------------------------------------*/

src/complain.h

@@ -1,5 +1,5 @@
 /* Declaration for error-reporting function for Bison.
-   Copyright (C) 2000, 2001, 2002, 2006 Free Software Foundation, Inc.
+   Copyright (C) 2000, 2001, 2002, 2006, 2009 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -39,6 +39,13 @@ void complain (char const *format, ...)
 void complain_at (location loc, char const *format, ...)
   __attribute__ ((__format__ (__printf__, 2, 3)));
 
+/** An incompatibility with POSIX Yacc: mapped either to warn* or
+    complain* depending on yacc_flag. */
+
+void yacc_at (location loc, char const *format, ...)
+  __attribute__ ((__format__ (__printf__, 2, 3)));
+
+
 /** A fatal error, causing immediate exit.  */
 
 void fatal (char const *format, ...)

src/output.c

@@ -490,9 +490,11 @@ token_definitions_output (FILE *out)
       if (sym->tag[0] == '\'' || sym->tag[0] == '\"')
 	continue;
 
-      /* Don't #define nonliteral tokens whose names contain periods
+      /* Don't #define nonliteral tokens whose names contain periods,
-	 or '$' (as does the default value of the EOF token).  */
+         dashes or '$' (as does the default value of the EOF token).  */
-      if (strchr (sym->tag, '.') || strchr (sym->tag, '$'))
+      if (strchr (sym->tag, '.')
+          || strchr (sym->tag, '-')
+          || strchr (sym->tag, '$'))
 	continue;
 
       fprintf (out, "%s[[[%s]], %d]",

src/parse-gram.y

@@ -535,15 +535,12 @@ rhs:
 
 variable:
   ID
-| STRING { $$ = uniqstr_new ($1); } /* deprecated and not M4-friendly */
+| STRING { $$ = uniqstr_new ($1); }
 ;
 
 /* Some content or empty by default. */
 content.opt:
-  /* Nothing. */
+  /* Nothing. */   { $$ = ""; }
-    {
-      $$ = "";
-    }
 | STRING
 ;
 

src/scan-gram.l

@@ -99,8 +99,8 @@ static void unexpected_newline (boundary, char const *);
 %x SC_STRING SC_CHARACTER
 
 letter	  [.abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_]
-id	  {letter}({letter}|[0-9])*
+id	  {letter}({letter}|[0-9]|-)*
-directive %{letter}({letter}|[0-9]|-)*
+directive %{id}
 int	  [0-9]+
 
 /* POSIX says that a tag must be both an id and a C union member, but
@@ -411,7 +411,7 @@ splice	 (\\[ \f\t\v]*\n)*
     unexpected_eof (token_start, "'");
     STRING_FINISH;
     loc->start = token_start;
-    if (strlen(last_string) > 1)
+    if (strlen (last_string) > 1)
       val->character = last_string[1];
     else
       val->character = last_string[0];

src/symtab.c

@@ -1,6 +1,7 @@
 /* Symbol table manager for Bison.
 
-   Copyright (C) 1984, 1989, 2000, 2001, 2002, 2004, 2005, 2006, 2007, 2008
+   Copyright (C) 1984, 1989, 2000, 2001, 2002, 2004, 2005, 2006, 2007,
+   2008, 2009
    Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
@@ -58,6 +59,13 @@ symbol_new (uniqstr tag, location loc)
   symbol *res = xmalloc (sizeof *res);
 
   uniqstr_assert (tag);
+
+  /* If the tag is not a string (starts with a double quote), check
+     that it is valid for Yacc. */
+  if (tag[0] != '\"' && tag[0] != '\'' && strchr (tag, '-'))
+    yacc_at (loc, _("POSIX Yacc forbids dashes in symbol names: %s"),
+             tag);
+
   res->tag = tag;
   res->location = loc;