Do not let the scan-skel token buffer grow unboundedly in the usual case.

[bison.git] / doc / bison.texinfo

diff --git a/doc/bison.texinfo b/doc/bison.texinfo
index 8d57aab7b96d851a7df97839f7479cbc9e81219b..8cabdb63e2452014cff3ae5deaa30800a7c1749e 100644 (file)
--- a/doc/bison.texinfo
+++ b/doc/bison.texinfo
@@ -3102,13 +3102,13 @@ When @code{YYLTYPE} is not defined, Bison uses a default structure type with
 four members:
 
 @example
-struct
+typedef struct YYLTYPE
 @{
   int first_line;
   int first_column;
   int last_line;
   int last_column;
-@}
+@} YYLTYPE;
 @end example
 
 @node Actions and Locations
@@ -3186,17 +3186,23 @@ Actually, actions are not the best place to compute locations.  Since
 locations are much more general than semantic values, there is room in
 the output parser to redefine the default action to take for each
 rule.  The @code{YYLLOC_DEFAULT} macro is invoked each time a rule is
-matched, before the associated action is run.
+matched, before the associated action is run.  It is also invoked
+while processing a syntax error, to compute the error's location.
 
 Most of the time, this macro is general enough to suppress location
 dedicated code from semantic actions.
 
 The @code{YYLLOC_DEFAULT} macro takes three parameters.  The first one is
-the location of the grouping (the result of the computation).  The second one
-is an array holding locations of all right hand side elements of the rule
-being matched.  The last one is the size of the right hand side rule.
+the location of the grouping (the result of the computation).  When a
+rule is matched, the second parameter is an array holding locations of
+all right hand side elements of the rule being matched, and the third
+parameter is the size of the rule's right hand side.  When processing
+a syntax error, the second parameter is an array holding locations of
+the symbols that were discarded during error processing, and the third
+parameter is the number of discarded symbols.
 
-By default, it is defined this way for simple @acronym{LALR}(1) parsers:
+By default, @code{YYLLOC_DEFAULT} is defined this way for simple
+@acronym{LALR}(1) parsers:
 
 @example
 @group
@@ -3417,7 +3423,23 @@ This says that the two alternative types are @code{double} and @code{symrec
 in the @code{%token} and @code{%type} declarations to pick one of the types
 for a terminal or nonterminal symbol (@pxref{Type Decl, ,Nonterminal Symbols}).
 
-Note that, unlike making a @code{union} declaration in C, you do not write
+As an extension to @acronym{POSIX}, a tag is allowed after the
+@code{union}.  For example:
+
+@example
+@group
+%union value @{
+  double val;
+  symrec *tptr;
+@}
+@end group
+@end example
+
+specifies the union tag @code{value}, so the corresponding C type is
+@code{union value}.  If you do not specify a tag, it defaults to
+@code{YYSTYPE}.
+
+Note that, unlike making a @code{union} declaration in C, you need not write
 a semicolon after the closing brace.
 
 @node Type Decl
@@ -3475,7 +3497,7 @@ should use @code{$$} to designate the semantic value associated to the
 (@pxref{Parser Function, , The Parser Function @code{yyparse}}).
 
 @strong{Warning:} as of Bison 1.875, this feature is still considered as
-experimental, as there was not enough users feedback.  In particular,
+experimental, as there was not enough user feedback.  In particular,
 the syntax might still change.
 @end deffn
 
@@ -5587,8 +5609,8 @@ useless: STR;
 @example
 calc.y: warning: 1 useless nonterminal and 1 useless rule
 calc.y:11.1-7: warning: useless nonterminal: useless
-calc.y:11.8-12: warning: useless rule: useless: STR
-calc.y contains 7 shift/reduce conflicts.
+calc.y:11.10-12: warning: useless rule: useless: STR
+calc.y: conflicts: 7 shift/reduce
 @end example
 
 When given @option{--report=state}, in addition to @file{calc.tab.c}, it
@@ -5610,10 +5632,10 @@ Conflict in state 8 between rule 2 and token '*' resolved as shift.
 The next section lists states that still have conflicts.
 
 @example
-State 8 contains 1 shift/reduce conflict.
-State 9 contains 1 shift/reduce conflict.
-State 10 contains 1 shift/reduce conflict.
-State 11 contains 4 shift/reduce conflicts.
+State 8 conflicts: 1 shift/reduce
+State 9 conflicts: 1 shift/reduce
+State 10 conflicts: 1 shift/reduce
+State 11 conflicts: 4 shift/reduce
 @end example
 
 @noindent
@@ -5825,8 +5847,8 @@ state 7
     exp         go to state 11
 @end example
 
-As was announced in beginning of the report, @samp{State 8 contains 1
-shift/reduce conflict}:
+As was announced in beginning of the report, @samp{State 8 conflicts:
+1 shift/reduce}:
 
 @example
 state 8
@@ -6452,15 +6474,11 @@ macro is deprecated, and is supported only for Yacc like parsers.
 @xref{Pure Calling,, Calling Conventions for Pure Parsers}.
 @end deffn
 
-@deffn {Macro} YYLTYPE
-Macro for the data type of @code{yylloc}; a structure with four
+@deffn {Type} YYLTYPE
+Data type of @code{yylloc}; by default, a structure with four
 members.  @xref{Location Type, , Data Types of Locations}.
 @end deffn
 
-@deffn {Type} yyltype
-Default value for YYLTYPE.
-@end deffn
-
 @deffn {Macro} YYMAXDEPTH
 Macro for specifying the maximum size of the parser stack.  @xref{Stack
 Overflow}.
@@ -6485,8 +6503,8 @@ grow its internal stacks.  Do @emph{not} define @code{YYSTACK_USE_ALLOCA}
 to anything else.
 @end deffn
 
-@deffn {Macro} YYSTYPE
-Macro for the data type of semantic values; @code{int} by default.
+@deffn {Type} YYSTYPE
+Data type of semantic values; @code{int} by default.
 @xref{Value Type, ,Data Types of Semantic Values}.
 @end deffn