Re: FYI: default %printer/%destructor

[Joel E. Denny]

On Sat, 18 Nov 2006, Joel E. Denny wrote:

> Does anyone else have comments?  If not, I think I'll soon rename <!> to 
> <>.

I committed this.

Index: ChangeLog
===================================================================
RCS file: /sources/bison/bison/ChangeLog,v
retrieving revision 1.1608
diff -p -u -r1.1608 ChangeLog
--- ChangeLog   17 Nov 2006 20:07:07 -0000      1.1608
+++ ChangeLog   21 Nov 2006 00:34:01 -0000
@@ -1,3 +1,23 @@
+2006-11-20  Joel E. Denny  <address@hidden>
+
+       Rename <!> to <>.  Discussed starting at
+       <http://lists.gnu.org/archive/html/bison-patches/2006-11/msg00039.html>.
+       * NEWS (2.3a+): Update.
+       * doc/bison.texinfo (Freeing Discarded Symbols, Bison Symbols):
+       Update.
+       * src/parse-gram.y (TYPE_TAG_NONE, generic_symlist_item): Implement.
+       * src/scan-gram.l (INITIAL): Implement.
+       * src/symlist.c (symbol_list_default_tagless_new): Update comment.
+       * src/symlist.h (symbol_list, symbol_list_default_tagless_new): Update
+       comment.
+       * tests/actions.at (Default tagless %printer and %destructor,
+       Default tagged and per-type %printer and %destructor,
+       Default %printer and %destructor are not for error or $undefined,
+       Default %printer and %destructor are not for $accept,
+       Default %printer and %destructor for mid-rule values): Update.
+       * tests/input.at (Default %printer and %destructor redeclared,
+       Unused values with default %destructor): Update.
+
 2006-11-17  Joel E. Denny  <address@hidden>
 
        Don't let %prec take a nonterminal.
@@ -160,7 +180,7 @@
        * doc/bison.texinfo (Freeing Discarded Symbols): Document this and the
        previous change today related to mid-rules.
        (Bison Symbols): Remove %symbol-default and add <*> and <!>.
-       * src/parser-gram.y (PERCENT_SYMBOL_DEFAULT): Remove.
+       * src/parse-gram.y (PERCENT_SYMBOL_DEFAULT): Remove.
        (TYPE_TAG_ANY): Add as <*>.
        (TYPE_TAG_NONE): Add as <!>.
        (generic_symlist_item): Remove RHS for %symbol-default and add RHS's
Index: NEWS
===================================================================
RCS file: /sources/bison/bison/NEWS,v
retrieving revision 1.165
diff -p -u -r1.165 NEWS
--- NEWS        1 Nov 2006 06:09:40 -0000       1.165
+++ NEWS        21 Nov 2006 00:34:02 -0000
@@ -33,12 +33,12 @@ Changes in version 2.3a+ (????-??-??):
        %destructor/%printer for all grammar symbols for which you have formally
        declared semantic type tags.
 
-    2. Place `<!>' in a %destructor/%printer symbol list to define a default
+    2. Place `<>' in a %destructor/%printer symbol list to define a default
        %destructor/%printer for all grammar symbols without declared semantic
        type tags.
 
   Bison no longer supports the `%symbol-default' notation from Bison 2.3a.
-  `<*>' and `<!>' combined achieve the same effect with one exception: Bison no
+  `<*>' and `<>' combined achieve the same effect with one exception: Bison no
   longer applies any %destructor to a mid-rule value if that mid-rule value is
   not actually ever referenced using either $$ or $n in a semantic action.
 
Index: doc/bison.texinfo
===================================================================
RCS file: /sources/bison/bison/doc/bison.texinfo,v
retrieving revision 1.211
diff -p -u -r1.211 bison.texinfo
--- doc/bison.texinfo   21 Oct 2006 10:03:35 -0000      1.211
+++ doc/bison.texinfo   21 Nov 2006 00:34:05 -0000
@@ -4237,7 +4237,7 @@ For instance, if your locations use a fi
 @cindex freeing discarded symbols
 @findex %destructor
 @findex <*>
address@hidden <!>
address@hidden <>
 During error recovery (@pxref{Error Recovery}), symbols already pushed
 on the stack and tokens coming from the rest of the file are discarded
 until the parser falls on its feet.  If the parser runs out of memory,
@@ -4271,7 +4271,7 @@ grammar symbol that has that semantic ty
 per-symbol @code{%destructor}.
 
 Finally, you can define two different kinds of default @code{%destructor}s.
-You can place each of @code{<*>} and @code{<!>} in the @var{symbols} list of
+You can place each of @code{<*>} and @code{<>} in the @var{symbols} list of
 exactly one @code{%destructor} declaration in your grammar file.
 The parser will invoke the @var{code} associated with one of these whenever it
 discards any user-defined grammar symbol that has no per-symbol and no per-type
@@ -4279,7 +4279,7 @@ discards any user-defined grammar symbol
 The parser uses the @var{code} for @code{<*>} in the case of such a grammar
 symbol for which you have formally declared a semantic type tag (@code{%type}
 counts as such a declaration, but @code{$<tag>$} does not).
-The parser uses the @var{code} for @code{<!>} in the case of such a grammar
+The parser uses the @var{code} for @code{<>} in the case of such a grammar
 symbol that has no declared semantic type tag.
 @end deffn
 
@@ -4300,7 +4300,7 @@ For example:
 %destructor @{ @} <character>
 %destructor @{ free ($$); @} <*>
 %destructor @{ free ($$); printf ("%d", @@$.first_line); @} STRING1 string1
-%destructor @{ printf ("Discarding tagless symbol.\n"); @} <!>
+%destructor @{ printf ("Discarding tagless symbol.\n"); @} <>
 @end smallexample
 
 @noindent
@@ -4339,7 +4339,7 @@ not reference @code{$$} in the mid-rule'
 @var{n} is the RHS symbol position of the mid-rule) in any later action in that
 rule.
 However, if you do reference either, the Bison-generated parser will invoke the
address@hidden<!>} @code{%destructor} whenever it discards the mid-rule symbol.
address@hidden<>} @code{%destructor} whenever it discards the mid-rule symbol.
 
 @ignore
 @noindent
@@ -8572,7 +8572,7 @@ Used to define a default tagged @code{%d
 @xref{Destructor Decl, , Freeing Discarded Symbols}.
 @end deffn
 
address@hidden {Directive} <!>
address@hidden {Directive} <>
 Used to define a default tagless @code{%destructor} or default tagless
 @code{%printer}.
 @xref{Destructor Decl, , Freeing Discarded Symbols}.
Index: src/parse-gram.y
===================================================================
RCS file: /sources/bison/bison/src/parse-gram.y,v
retrieving revision 1.98
diff -p -u -r1.98 parse-gram.y
--- src/parse-gram.y    12 Nov 2006 07:39:37 -0000      1.98
+++ src/parse-gram.y    21 Nov 2006 00:34:06 -0000
@@ -176,7 +176,7 @@ static int current_prec = 0;
 %token SEMICOLON       ";"
 %token TYPE            "type"
 %token TYPE_TAG_ANY    "<*>"
-%token TYPE_TAG_NONE   "<!>"
+%token TYPE_TAG_NONE   "<>"
 
 %type <character> CHAR
 %printer { fputs (char_name ($$), stderr); } CHAR
@@ -397,7 +397,7 @@ generic_symlist_item:
   symbol            { $$ = symbol_list_sym_new ($1, @1); }
 | TYPE              { $$ = symbol_list_type_new ($1, @1); }
 | "<*>"             { $$ = symbol_list_default_tagged_new (@1); }
-| "<!>"             { $$ = symbol_list_default_tagless_new (@1); }
+| "<>"             { $$ = symbol_list_default_tagless_new (@1); }
 ;
 
 /* One token definition.  */
Index: src/scan-gram.l
===================================================================
RCS file: /sources/bison/bison/src/scan-gram.l,v
retrieving revision 1.110
diff -p -u -r1.110 scan-gram.l
--- src/scan-gram.l     12 Nov 2006 07:39:37 -0000      1.110
+++ src/scan-gram.l     21 Nov 2006 00:34:06 -0000
@@ -210,7 +210,7 @@ splice       (\\[ \f\t\v]*\n)*
   "|"                     return PIPE;
   ";"                     return SEMICOLON;
   "<*>"                   return TYPE_TAG_ANY;
-  "<!>"                   return TYPE_TAG_NONE;
+  "<>"                    return TYPE_TAG_NONE;
 
   {id} {
     val->uniqstr = uniqstr_new (yytext);
Index: src/symlist.c
===================================================================
RCS file: /sources/bison/bison/src/symlist.c,v
retrieving revision 1.25
diff -p -u -r1.25 symlist.c
--- src/symlist.c       12 Nov 2006 07:39:37 -0000      1.25
+++ src/symlist.c       21 Nov 2006 00:34:06 -0000
@@ -91,9 +91,9 @@ symbol_list_default_tagged_new (location
 }
 
 
-/*----------------------------------------.
-| Create a list containing a <!> at LOC.  |
-`----------------------------------------*/
+/*---------------------------------------.
+| Create a list containing a <> at LOC.  |
+`---------------------------------------*/
 
 symbol_list *
 symbol_list_default_tagless_new (location loc)
Index: src/symlist.h
===================================================================
RCS file: /sources/bison/bison/src/symlist.h,v
retrieving revision 1.22
diff -p -u -r1.22 symlist.h
--- src/symlist.h       12 Nov 2006 07:39:37 -0000      1.22
+++ src/symlist.h       21 Nov 2006 00:34:06 -0000
@@ -30,7 +30,7 @@ typedef struct symbol_list
 {
   /**
    * Whether this node contains a symbol, a semantic type, a \c <*>, or a
-   * \c <!>.
+   * \c <>.
    */
   enum {
     SYMLIST_SYMBOL, SYMLIST_TYPE,
@@ -81,7 +81,7 @@ symbol_list *symbol_list_type_new (uniqs
 
 /** Create a list containing a \c <*> at \c loc.  */
 symbol_list *symbol_list_default_tagged_new (location loc);
-/** Create a list containing a \c <!> at \c loc.  */
+/** Create a list containing a \c <> at \c loc.  */
 symbol_list *symbol_list_default_tagless_new (location loc);
 
 /** Print this list.
Index: tests/actions.at
===================================================================
RCS file: /sources/bison/bison/tests/actions.at,v
retrieving revision 1.74
diff -p -u -r1.74 actions.at
--- tests/actions.at    21 Oct 2006 10:03:35 -0000      1.74
+++ tests/actions.at    21 Nov 2006 00:34:06 -0000
@@ -614,11 +614,11 @@ AT_DATA_GRAMMAR([[input.y]],
 } <*>
 
 %printer {
-  fprintf (yyoutput, "<!> printer for '%c' @ %d", $$, @$.first_column);
-} <!>
+  fprintf (yyoutput, "<> printer for '%c' @ %d", $$, @$.first_column);
+} <>
 %destructor {
-  fprintf (stdout, "<!> destructor for '%c' @ %d.\n", $$, @$.first_column);
-} <!>
+  fprintf (stdout, "<> destructor for '%c' @ %d.\n", $$, @$.first_column);
+} <>
 
 %printer {
   fprintf (yyoutput, "'b'/'c' printer for '%c' @ %d", $$, @$.first_column);
@@ -667,15 +667,15 @@ main (void)
 AT_CHECK([bison -o input.c input.y])
 AT_COMPILE([input])
 AT_PARSER_CHECK([./input], 1,
-[[<!> destructor for 'd' @ 4.
+[[<> destructor for 'd' @ 4.
 'b'/'c' destructor for 'c' @ 3.
 'b'/'c' destructor for 'b' @ 2.
-<!> destructor for 'a' @ 1.
+<> destructor for 'a' @ 1.
 ]],
 [[Starting parse
 Entering state 0
-Reading a token: Next token is token 'a' (1.1-1.1: <!> printer for 'a' @ 1)
-Shifting token 'a' (1.1-1.1: <!> printer for 'a' @ 1)
+Reading a token: Next token is token 'a' (1.1-1.1: <> printer for 'a' @ 1)
+Shifting token 'a' (1.1-1.1: <> printer for 'a' @ 1)
 Entering state 1
 Reading a token: Next token is token 'b' (1.2-1.2: 'b'/'c' printer for 'b' @ 2)
 Shifting token 'b' (1.2-1.2: 'b'/'c' printer for 'b' @ 2)
@@ -683,18 +683,18 @@ Entering state 3
 Reading a token: Next token is token 'c' (1.3-1.3: 'b'/'c' printer for 'c' @ 3)
 Shifting token 'c' (1.3-1.3: 'b'/'c' printer for 'c' @ 3)
 Entering state 5
-Reading a token: Next token is token 'd' (1.4-1.4: <!> printer for 'd' @ 4)
-Shifting token 'd' (1.4-1.4: <!> printer for 'd' @ 4)
+Reading a token: Next token is token 'd' (1.4-1.4: <> printer for 'd' @ 4)
+Shifting token 'd' (1.4-1.4: <> printer for 'd' @ 4)
 Entering state 6
 Reading a token: Now at end of input.
 syntax error, unexpected $end, expecting 'e'
-Error: popping token 'd' (1.4-1.4: <!> printer for 'd' @ 4)
+Error: popping token 'd' (1.4-1.4: <> printer for 'd' @ 4)
 Stack now 0 1 3 5
 Error: popping token 'c' (1.3-1.3: 'b'/'c' printer for 'c' @ 3)
 Stack now 0 1 3
 Error: popping token 'b' (1.2-1.2: 'b'/'c' printer for 'b' @ 2)
 Stack now 0 1
-Error: popping token 'a' (1.1-1.1: <!> printer for 'a' @ 1)
+Error: popping token 'a' (1.1-1.1: <> printer for 'a' @ 1)
 Stack now 0
 Cleanup: discarding lookahead token $end (1.5-1.5: )
 Stack now 0
@@ -723,8 +723,8 @@ AT_DATA_GRAMMAR([[input.y]],
 %}
 
 %printer {
-  fprintf (yyoutput, "<!> printer should not be called.\n");
-} <!>
+  fprintf (yyoutput, "<> printer should not be called.\n");
+} <>
 
 %union { int field0; int field1; int field2; }
 %type <field0> start 'a' 'g'
@@ -750,8 +750,8 @@ AT_DATA_GRAMMAR([[input.y]],
 %destructor { fprintf (stdout, "'d' destructor.\n"); } 'd'
 
 %destructor {
-  fprintf (yyoutput, "<!> destructor should not be called.\n");
-} <!>
+  fprintf (yyoutput, "<> destructor should not be called.\n");
+} <>
 
 %%
 
@@ -851,8 +851,8 @@ AT_SETUP([Default %printer and %destruct
 # -----------------------------------------------------------------------------
 m4_define([_AT_CHECK_DEFAULT_PRINTER_AND_DESTRUCTOR_FOR_END_TOKEN],
 [m4_if($1, 0,
-  [m4_pushdef([kind], [!]) m4_pushdef([not_kind], [*])],
-  [m4_pushdef([kind], [*]) m4_pushdef([not_kind], [!])])
+  [m4_pushdef([kind], []) m4_pushdef([not_kind], [*])],
+  [m4_pushdef([kind], [*]) m4_pushdef([not_kind], [])])
 
 AT_DATA_GRAMMAR([[input]]$1[[.y]],
 [[%error-verbose
@@ -983,10 +983,10 @@ AT_DATA_GRAMMAR([[input.y]],
 
 %printer {
   fprintf (yyoutput, "'%c'", $$);
-} <!> <*>
+} <> <*>
 %destructor {
   fprintf (stderr, "DESTROY '%c'\n", $$);
-} <!> <*>
+} <> <*>
 
 %%
 
@@ -1098,11 +1098,11 @@ AT_DATA_GRAMMAR([[input.y]],
 %printer {
   char chr = $$;
   fprintf (yyoutput, "'%c'", chr);
-} <!> <*>
+} <> <*>
 %destructor {
   char chr = $$;
   fprintf (stderr, "DESTROY '%c'\n", chr);
-} <!> <*>
+} <> <*>
 
 %union { char chr; }
 %type <chr> start
@@ -1162,8 +1162,8 @@ AT_DATA_GRAMMAR([[input.y]],
 # define YY_LOCATION_PRINT(File, Loc)
 %}
 
-%printer { fprintf (yyoutput, "%d", @$); } <!>
-%destructor { fprintf (stderr, "DESTROY %d\n", @$); } <!>
+%printer { fprintf (yyoutput, "%d", @$); } <>
+%destructor { fprintf (stderr, "DESTROY %d\n", @$); } <>
 %printer { fprintf (yyoutput, "<*> printer should not be called"); } <*>
 %destructor { fprintf (yyoutput, "<*> destructor should not be called"); } <*>
 
Index: tests/input.at
===================================================================
RCS file: /sources/bison/bison/tests/input.at,v
retrieving revision 1.62
diff -p -u -r1.62 input.at
--- tests/input.at      17 Nov 2006 20:07:08 -0000      1.62
+++ tests/input.at      21 Nov 2006 00:34:06 -0000
@@ -188,11 +188,11 @@ AT_DATA([[input.y]],
 %destructor { destroy ($$); } <*>
 %printer { destroy ($$); } <*>
 
-%destructor { destroy ($$); } <!> <!>
-%printer { destroy ($$); } <!> <!>
+%destructor { destroy ($$); } <> <>
+%printer { destroy ($$); } <> <>
 
-%destructor { destroy ($$); } <!>
-%printer { destroy ($$); } <!>
+%destructor { destroy ($$); } <>
+%printer { destroy ($$); } <>
 
 %%
 
@@ -201,8 +201,8 @@ start: ;
 %destructor { destroy ($$); } <*>;
 %printer { destroy ($$); } <*>;
 
-%destructor { destroy ($$); } <!>;
-%printer { destroy ($$); } <!>;
+%destructor { destroy ($$); } <>;
+%printer { destroy ($$); } <>;
 ]])
 
 AT_CHECK([bison input.y], [1], [],
@@ -285,7 +285,7 @@ AT_CLEANUP
 AT_SETUP([Unused values with default %destructor])
 
 AT_DATA([[input.y]],
-[[%destructor { destroy ($$); } <!>
+[[%destructor { destroy ($$); } <>
 %type <tag> tagged
 
 %%