Re: [PATCH 1/2] symbols: improve symbol aliasing

[Akim Demaille]

Le 31 juil. 2013 à 10:22, Akim Demaille <address@hidden> a écrit :

> 
> Le 30 juil. 2013 à 18:41, Valentin Tolmer <address@hidden> a écrit :
> 
>>> 
>>> Don't you think that these guys should still work on symbols
>>> as before, but process their content behind the scenes?
>>> 
>>> I think that these changes should be mostly internal, and
>>> virtualy invisible from the call sites.
>>> 
>> I thought so, too, but apart from somewhat simplifying the code, it seemed 
>> to make more sense to call the function on the content, as this is what we 
>> want to modify.
> 
> I think that the caller does not need to know what she
> is modifying.  She basically wants to change information
> about the symbols, and how symbols are implemented is not
> her business.  Unfortunately, because we don't provide
> accessors, eventually the implementation shows, when reading
> these fields; but in C++ for instance, we would have hidden
> this.
> 
>> But if you think it's better to make the changes transparent, I understand, 
>> and will revert.
> 
> I think it is better to hide this, yes.

I'm about to push your patch in {master}, with the following changes.
Don't publish in NEWS what _users_ can't see; NEWS is not for
the developers (git log is :).

diff --git a/NEWS b/NEWS
index 67f4633..3e783ee 100644
--- a/NEWS
+++ b/NEWS
@@ -2,16 +2,6 @@ GNU Bison NEWS
 
 * Noteworthy changes in release ?.? (????-??-??) [?]
 
-** Alias improvement
-
-  Aliases were formerly handled this way: information about the symbol was
-  repeated in the symbol and the alias, and any discrepancy was resolved
-  after reading the whole grammar.
-
-  Now, however, the symbol and the alias share a pointer to a separate
-  structure containing the common information, and any incompatible
-  statement is thus detected at the moment it is read.
-
 * Noteworthy changes in release 3.0 (2013-07-25) [stable]
 
 ** WARNING: Future backward-incompatibilities!
diff --git a/src/print.c b/src/print.c
index 94d3d2d..f8ed3da 100644
--- a/src/print.c
+++ b/src/print.c
@@ -258,7 +258,7 @@ print_reductions (FILE *out, state *s)
     bitset_set (no_reduce_set, TRANSITION_SYMBOL (trans, i));
   for (i = 0; i < s->errs->num; ++i)
     if (s->errs->symbols[i])
-        bitset_set (no_reduce_set, s->errs->symbols[i]->content->number);
+      bitset_set (no_reduce_set, s->errs->symbols[i]->content->number);
 
   /* Compute the width of the lookahead token column.  */
   if (default_reduction)
diff --git a/src/reduce.c b/src/reduce.c
index 23ab7e4..e79d205 100644
--- a/src/reduce.c
+++ b/src/reduce.c
@@ -196,9 +196,9 @@ inaccessable_symbols (void)
   V = Vp;
 
   /* Tokens 0, 1, and 2 are internal to Bison.  Consider them useful. */
-  bitset_set (V, endtoken->content->number);             /* end-of-input token 
*/
-  bitset_set (V, errtoken->content->number);             /* error token */
-  bitset_set (V, undeftoken->content->number);           /* some undefined 
token */
+  bitset_set (V, endtoken->content->number);   /* end-of-input token */
+  bitset_set (V, errtoken->content->number);   /* error token */
+  bitset_set (V, undeftoken->content->number); /* some undefined token */
 
   bitset_free (P);
   P = Pp;

Also, I have changed your commit message to use a better author,
and a style which is consistent with the remainder of our commits.

commit a7280757105b2909f6a58fdd1c582de8e278319a
Author: Valentin Tolmer <address@hidden>
Date:   Wed Jul 31 11:51:59 2013 +0200

    symbols: improve symbol aliasing
    
    Rather than having duplicate info in the symbol and the alias that has
    to be resolved later on, both the symbol and the alias have a common
    pointer to a separate structure containing this info.
    
    * src/symtab.h (sym_content): New structure.
    * src/symtab.c (sym_content_new, sym_content_free, symbol_free): New
    
    * src/AnnotationList.c, src/conflicts.c, src/gram.c, src/gram.h,
    * src/graphviz.c, src/ielr.c, src/output.c, src/parse-gram.y, src/print.c
    * src/print-xml.c, src/print_graph.c, src/reader.c, src/reduce.c,
    * src/state.h, src/symlist.c, src/symtab.c, src/symtab.h, src/tables.c:
    Adjust.
    
    * tests/input.at: Fix expectations (order changes).