* src/parse-gram.y: Define PERCENT_EXPECT_RR.

[bison.git] / doc / bison.texinfo

diff --git a/doc/bison.texinfo b/doc/bison.texinfo
index c1bff43ca1f832211d171865c608cd62dcc16215..22e5da910da69dc3175c599a52794b34bf8bfa7d 100644 (file)
--- a/doc/bison.texinfo
+++ b/doc/bison.texinfo
@@ -44,7 +44,7 @@ This manual is for @acronym{GNU} Bison (version @value{VERSION},
 @value{UPDATED}), the @acronym{GNU} parser generator.
 
 Copyright @copyright{} 1988, 1989, 1990, 1991, 1992, 1993, 1995, 1998,
-1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
+1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
 
 @quotation
 Permission is granted to copy, distribute and/or modify this document
@@ -223,7 +223,7 @@ Bison Declarations
 * Union Decl::        Declaring the set of all semantic value types.
 * Type Decl::         Declaring the choice of type for a nonterminal symbol.
 * Destructor Decl::   Declaring how symbols are freed.
-* Expect Decl::       Suppressing warnings about shift/reduce conflicts.
+* Expect Decl::       Suppressing warnings about parsing conflicts.
 * Start Decl::        Specifying the start symbol.
 * Pure Decl::         Requesting a reentrant parser.
 * Decl Summary::      Table of all Bison declarations.
@@ -356,7 +356,7 @@ encourage people to make other software free.  So we decided to make the
 practical conditions for using Bison match the practical conditions for
 using the other @acronym{GNU} tools.
 
-This exception applies only when Bison is generating C code for a
+This exception applies only when Bison is generating C code for an
 @acronym{LALR}(1) parser; otherwise, the @acronym{GPL} terms operate
 as usual.  You can
 tell whether the exception applies to your @samp{.c} output file by
@@ -3280,7 +3280,7 @@ Grammars}).
 * Union Decl::        Declaring the set of all semantic value types.
 * Type Decl::         Declaring the choice of type for a nonterminal symbol.
 * Destructor Decl::   Declaring how symbols are freed.
-* Expect Decl::       Suppressing warnings about shift/reduce conflicts.
+* Expect Decl::       Suppressing warnings about parsing conflicts.
 * Start Decl::        Specifying the start symbol.
 * Pure Decl::         Requesting a reentrant parser.
 * Decl Summary::      Table of all Bison declarations.
@@ -3309,10 +3309,12 @@ associativity and precedence.  @xref{Precedence Decl, ,Operator
 Precedence}.
 
 You can explicitly specify the numeric code for a token type by appending
-an integer value in the field immediately following the token name:
+a decimal or hexadecimal integer value in the field immediately
+following the token name:
 
 @example
 %token NUM 300
+%token XNUM 0x12d // a GNU extension
 @end example
 
 @noindent
@@ -3558,6 +3560,7 @@ typefull: string;  // $$ = $1 applies, $1 is not destroyed.
 @cindex warnings, preventing
 @cindex conflicts, suppressing warnings of
 @findex %expect
+@findex %expect-rr
 
 Bison normally warns if there are any conflicts in the grammar
 (@pxref{Shift/Reduce, ,Shift/Reduce Conflicts}), but most real grammars
@@ -3578,6 +3581,18 @@ reduce/reduce conflicts.  The usual warning is
 given if there are either more or fewer conflicts, or if there are any
 reduce/reduce conflicts.
 
+For normal LALR(1) parsers, reduce/reduce conflicts are more serious,
+and should be eliminated entirely.  Bison will always report
+reduce/reduce conflicts for these parsers.  With GLR parsers, however,
+both shift/reduce and reduce/reduce are routine (otherwise, there
+would be no need to use GLR parsing).  Therefore, it is also possible
+to specify an expected number of reduce/reduce conflicts in GLR
+parsers, using the declaration:
+
+@example
+%expect-rr @var{n}
+@end example
+
 In general, using @code{%expect} involves these steps:
 
 @itemize @bullet
@@ -6214,7 +6229,7 @@ compatibility with @acronym{POSIX}:
 
 @example
 #! /bin/sh
-bison -y "$@"
+bison -y "$@@"
 @end example
 @end table
 
@@ -6508,6 +6523,11 @@ handle features like include files, you might consider using Flex
 functions like @samp{yy_switch_to_buffer} that manipulate multiple
 input buffers.
 
+If your Flex-generated scanner uses start conditions (@pxref{Start
+conditions, , Start conditions, flex, The Flex Manual}), you might
+also want to reset the scanner's state, i.e., go back to the initial
+start condition, through a call to @samp{BEGIN (0)}.
+
 @node Strings are Destroyed
 @section Strings are Destroyed