Re: [PATCH 0/6] api.value.type support

[Akim Demaille]

Le 25 févr. 2013 à 14:26, Akim Demaille <address@hidden> a écrit :

> So far --yacc/--fixed-output-file triggers the following changes:
> - -Werror=yacc is enabled
> - we use "#define TOKEN…" in addition to "enum { TOKEN … }"
> - output names are y.tab.h, y.tab.c, and y.output
> - a missing `;' will not added to the end of the actions
> 
> This last "feature" is deprecated, and actually I think I will
> remove it just now.  There was a deprecation message for a
> while, and I had not realized that -y disabled this feature
> anyway, so really there's no point in keeping it.  Bison
> 3.0 is already dropping support for ancient features, so now
> is no worse that 3.1.

Here's my proposal.

commit e1ae442f5b5adc2277a405bff1940ef4d12df435
Author: Akim Demaille <address@hidden>
Date:   Mon Feb 25 15:33:55 2013 +0100

    grammar: no longer detect and cure missing semicolon at end of actions
    
    Bison 3.0 is already breaking backward compatibility with other
    features.  It is an appropriate time to drop this feature.  Note that
    it was disabled when --yacc is passed.  See
    http://lists.gnu.org/archive/html/bison-patches/2013-02/msg00102.html
    
    Basically, revert e8cd1ad655bcc704b06fb2f191dc3ac1df32b796.
    
    * src/scan-code.l (braces_level, need_semicolon, in_cpp): Remove.
    Remove every rule needed to detect and add missing semicolon.
    * tests/actions.at (Fix user actions without a trailing semicolon):
    Remove.
    * NEWS: Adjust.
---
 NEWS             |  11 ++----
 src/scan-code.l  |  86 +++----------------------------------------
 tests/actions.at | 109 -------------------------------------------------------
 3 files changed, 8 insertions(+), 198 deletions(-)

diff --git a/NEWS b/NEWS
index 57866ab..0db6549 100644
--- a/NEWS
+++ b/NEWS
@@ -4,14 +4,6 @@ GNU Bison NEWS
 
 ** WARNING: Future backward-incompatibilities!
 
-  Bison will stop adding a semicolon at the end of the actions (as announced
-  in the release 2.5):
-
-    foo.y:2.25: warning: a ';' might be needed at the end of action code
-     exp: "number" { $$ = $1 }
-                             ^
-    foo.y:2.25:     future versions of Bison will not add the ';'
-
   Like other GNU packages, Bison will start using some of the C99 features
   for its own code, especially the definition of variables after statements.
   The generated C parsers still aim at C90.
@@ -28,6 +20,9 @@ GNU Bison NEWS
   Support for YYLEX_PARAM and YYPARSE_PARAM is removed (deprecated in Bison
   1.875): use %lex-param, %parse-param, or %param.
 
+  Missing semicolons at the end of actions are no longer added (as announced
+  in the release 2.5).
+
 ** Bug fixes
 
 *** The epilogue is no longer affected by internal #defines (glr.c)
diff --git a/src/scan-code.l b/src/scan-code.l
index b9840b1..cced97b 100644
--- a/src/scan-code.l
+++ b/src/scan-code.l
@@ -96,26 +96,6 @@ ref      -?[0-9]+|{id}|"["{id}"]"|"$"
 %%
 
 %{
-  /* Nesting level of the current code in braces.  */
-  int braces_level = 0;
-
-  /* Whether a semicolon is probably needed.
-
-     The heuristic is that a semicolon is not needed after '{', '}',
-     ';', or a C preprocessor directive, and that whitespaces and
-     comments do not affect this flag.  Note that '{' does not need a
-     semicolon because of '{}'.  A semicolon may be needed before a
-     cpp directive, but don't bother.
-
-     While it is maintained in several start-conditions (factoring
-     opportunities), it is meaningful only for SC_RULE_ACTION. */
-  bool need_semicolon = false;
-
-  /* Whether in a C preprocessor directive.  Don't use a start condition
-     for this because, at the end of strings and comments, we still need
-     to know whether we're in a directive.  */
-  bool in_cpp = false;
-
   /* This scanner is special: it is invoked only once, henceforth
      is expected to return only once.  This initialization is
      therefore done once per action to translate. */
@@ -168,32 +148,14 @@ ref      -?[0-9]+|{id}|"["{id}"]"|"$"
 
 <SC_RULE_ACTION,SC_SYMBOL_ACTION>
 {
-  "'" {
-    STRING_GROW;
-    BEGIN SC_CHARACTER;
-    need_semicolon = true;
-  }
-  "\"" {
-    STRING_GROW;
-    BEGIN SC_STRING;
-    need_semicolon = true;
-  }
-  "/"{splice}"*" {
-    STRING_GROW;
-    BEGIN SC_COMMENT;
-  }
-  "/"{splice}"/" {
-    STRING_GROW;
-    BEGIN SC_LINE_COMMENT;
-  }
+  "'"              STRING_GROW; BEGIN SC_CHARACTER;
+  "\""             STRING_GROW; BEGIN SC_STRING;
+  "/"{splice}"*"   STRING_GROW; BEGIN SC_COMMENT;
+  "/"{splice}"/"   STRING_GROW; BEGIN SC_LINE_COMMENT;
+
   address@hidden  {
     complain (loc, Wother, _("stray '%s'"), yytext);
     obstack_escape (&obstack_for_string, yytext);
-    need_semicolon = true;
-  }
-  [\[\]]  {
-    obstack_escape (&obstack_for_string, yytext);
-    need_semicolon = true;
   }
 }
 
@@ -204,51 +166,13 @@ ref      -?[0-9]+|{id}|"["{id}"]"|"$"
     handle_action_dollar (self->rule, yytext, *loc);
     if (ref_tail_fields)
       obstack_sgrow (&obstack_for_string, ref_tail_fields);
-    need_semicolon = true;
   }
   "@"{ref} {
     ref_tail_fields = NULL;
     handle_action_at (self->rule, yytext, *loc);
     if (ref_tail_fields)
       obstack_sgrow (&obstack_for_string, ref_tail_fields);
-    need_semicolon = true;
-  }
-
-  ";"  STRING_GROW;                 need_semicolon = false;
-  "{"  STRING_GROW; ++braces_level; need_semicolon = false;
-  "}"  {
-    bool outer_brace = --braces_level == 0;
-
-    /* As an undocumented Bison extension, append ';' before the last
-       brace in braced code, so that the user code can omit trailing
-       ';'.  But do not append ';' if emulating Yacc, since Yacc does
-       not append one.  This is deprecated since release 2.4.1.  */
-    if (outer_brace && !yacc_flag && language_prio == default_prio
-        && skeleton_prio == default_prio && need_semicolon && ! in_cpp)
-      {
-        unsigned int indent = 0;
-        complain_indent (loc, Wdeprecated, &indent,
-                         _("a ';' might be needed at the end of action code"));
-        indent += SUB_INDENT;
-        complain_indent (loc, Wdeprecated | silent | no_caret, &indent,
-                         _("future versions of Bison will not add the ';'"));
-        obstack_1grow (&obstack_for_string, ';');
-      }
-
-    STRING_GROW;
-    need_semicolon = false;
   }
-
-  /* Preprocessing directives should only be recognized at the beginning
-     of lines, allowing whitespace including comments, but in C/C++,
-     '#' can only be the start of preprocessor directives or within
-     '#define' directives anyway, so don't bother with begin of line.  */
-  "#"       STRING_GROW; in_cpp = true;
-
-  {splice}  STRING_GROW;
-  [\n\r]    STRING_GROW; if (in_cpp) in_cpp = need_semicolon = false;
-  [ \t\f]   STRING_GROW;
-  .         STRING_GROW; need_semicolon = true;
 }
 
 <SC_SYMBOL_ACTION>
diff --git a/tests/actions.at b/tests/actions.at
index 3021c7a..b169513 100644
--- a/tests/actions.at
+++ b/tests/actions.at
@@ -1607,115 +1607,6 @@ AT_TEST([glr.cc])
 
 m4_popdef([AT_TEST])
 
-## ----------------------------------------------- ##
-## Fix user actions without a trailing semicolon.  ##
-## ----------------------------------------------- ##
-
-AT_SETUP([[Fix user actions without a trailing semicolon]])
-
-# This feature is undocumented, but we accidentally broke it in 2.3a,
-# and there was a complaint at:
-# <http://lists.gnu.org/archive/html/bug-bison/2008-11/msg00001.html>.
-AT_BISON_OPTION_PUSHDEFS
-AT_DATA([input.y],
-[[%%
-start: test2 test1 test0 testc;
-
-test2
-: 'a' { semi;                   /* TEST:N:2 */ }
-| 'b' { if (0) {no_semi}        /* TEST:N:2 */ }
-| 'c' { if (0) {semi;}          /* TEST:N:2 */ }
-| 'd' { semi;   no_semi         /* TEST:Y:2 */ }
-| 'e' { semi(); no_semi()       /* TEST:Y:2 */ }
-| 'f' { semi[]; no_semi[]       /* TEST:Y:2 */ }
-| 'g' { semi++; no_semi++       /* TEST:Y:2 */ }
-| 'h' { {no_semi} no_semi       /* TEST:Y:2 */ }
-| 'i' { {semi;}   no_semi       /* TEST:Y:2 */ }
-;
-test1
-  : 'a' { semi;                 // TEST:N:1 ;
-} | 'b' { if (0) {no_semi}      // TEST:N:1 ;
-} | 'c' { if (0) {semi;}        // TEST:N:1 ;
-} | 'd' { semi;   no_semi       // TEST:Y:1 ;
-} | 'e' { semi(); no_semi()     // TEST:Y:1 ;
-} | 'f' { semi[]; no_semi[]     // TEST:Y:1 ;
-} | 'g' { semi++; no_semi++     // TEST:Y:1 ;
-} | 'h' { {no_semi} no_semi     // TEST:Y:1 ;
-} | 'i' { {semi;}   no_semi     // TEST:Y:1 ;
-} ;
-test0
-  : 'a' { semi;                 // TEST:N:1 {}
-} | 'b' { if (0) {no_semi}      // TEST:N:1 {}
-} | 'c' { if (0) {semi;}        // TEST:N:1 {}
-} | 'd' { semi;   no_semi       // TEST:Y:1 {}
-} | 'e' { semi(); no_semi()     // TEST:Y:1 {}
-} | 'f' { semi[]; no_semi[]     // TEST:Y:1 {}
-} | 'g' { semi++; no_semi++     // TEST:Y:1 {}
-} | 'h' { {no_semi} no_semi     // TEST:Y:1 {}
-} | 'i' { {semi;}   no_semi     // TEST:Y:1 {}
-} ;
-
-testc
-: 'a' {
-#define TEST_MACRO_N \
-[]"broken\" $ @ $$ @$ [];\
-string;"}
-| 'b' {
-no_semi
-#define TEST_MACRO_N \
-[]"broken\" $ @ $$ @$ [];\
-string;"}
-]])
-AT_BISON_OPTION_POPDEFS
-
-AT_BISON_CHECK([[-o input.c input.y]], [0], [],
-[[input.y:8.48: warning: a ';' might be needed at the end of action code 
[-Wdeprecated]
-input.y:8.48:     future versions of Bison will not add the ';'
-input.y:9.48: warning: a ';' might be needed at the end of action code 
[-Wdeprecated]
-input.y:9.48:     future versions of Bison will not add the ';'
-input.y:10.48: warning: a ';' might be needed at the end of action code 
[-Wdeprecated]
-input.y:10.48:     future versions of Bison will not add the ';'
-input.y:11.48: warning: a ';' might be needed at the end of action code 
[-Wdeprecated]
-input.y:11.48:     future versions of Bison will not add the ';'
-input.y:12.48: warning: a ';' might be needed at the end of action code 
[-Wdeprecated]
-input.y:12.48:     future versions of Bison will not add the ';'
-input.y:13.48: warning: a ';' might be needed at the end of action code 
[-Wdeprecated]
-input.y:13.48:     future versions of Bison will not add the ';'
-input.y:20.1: warning: a ';' might be needed at the end of action code 
[-Wdeprecated]
-input.y:20.1:     future versions of Bison will not add the ';'
-input.y:21.1: warning: a ';' might be needed at the end of action code 
[-Wdeprecated]
-input.y:21.1:     future versions of Bison will not add the ';'
-input.y:22.1: warning: a ';' might be needed at the end of action code 
[-Wdeprecated]
-input.y:22.1:     future versions of Bison will not add the ';'
-input.y:23.1: warning: a ';' might be needed at the end of action code 
[-Wdeprecated]
-input.y:23.1:     future versions of Bison will not add the ';'
-input.y:24.1: warning: a ';' might be needed at the end of action code 
[-Wdeprecated]
-input.y:24.1:     future versions of Bison will not add the ';'
-input.y:25.1: warning: a ';' might be needed at the end of action code 
[-Wdeprecated]
-input.y:25.1:     future versions of Bison will not add the ';'
-input.y:31.1: warning: a ';' might be needed at the end of action code 
[-Wdeprecated]
-input.y:31.1:     future versions of Bison will not add the ';'
-input.y:32.1: warning: a ';' might be needed at the end of action code 
[-Wdeprecated]
-input.y:32.1:     future versions of Bison will not add the ';'
-input.y:33.1: warning: a ';' might be needed at the end of action code 
[-Wdeprecated]
-input.y:33.1:     future versions of Bison will not add the ';'
-input.y:34.1: warning: a ';' might be needed at the end of action code 
[-Wdeprecated]
-input.y:34.1:     future versions of Bison will not add the ';'
-input.y:35.1: warning: a ';' might be needed at the end of action code 
[-Wdeprecated]
-input.y:35.1:     future versions of Bison will not add the ';'
-input.y:36.1: warning: a ';' might be needed at the end of action code 
[-Wdeprecated]
-input.y:36.1:     future versions of Bison will not add the ';'
-]])
-
-AT_MATCHES_CHECK([input.c], [[/\* TEST:N:2 \*/ \}$]],       [[3]])
-AT_MATCHES_CHECK([input.c], [[/\* TEST:Y:2 \*/ ;\}$]],      [[6]])
-AT_MATCHES_CHECK([input.c], [[// TEST:N:1 [;{}]*\n\}$]],    [[6]])
-AT_MATCHES_CHECK([input.c], [[// TEST:Y:1 [;{}]*\n;\}$]],  [[12]])
-AT_MATCHES_CHECK([input.c], [[#define TEST_MACRO_N \\\n\[\]"broken\\" \$ \@ 
\$\$ address@hidden \[\];\\\nstring;"\}]], [[2]])
-
-AT_CLEANUP
-
-
 ## -------------------------------------------------- ##
 ## Destroying lookahead assigned by semantic action.  ##
 ## -------------------------------------------------- ##