Use variants to support objects as semantic values.

[bison.git] / ChangeLog

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+2008-11-03  Akim Demaille  <demaille@gostai.com>
+
+       Use variants to support objects as semantic values.
+       This patch was inspired by work by Michiel De Wilde.  But he used Boost
+       variants which (i) requires Boost on the user side, (ii) is slow, and
+       (iii) has useless overhead (the parser knows the type of the semantic value
+       there is no reason to duplicate this information as Boost.Variants do).
+       
+       This implementation reserves a buffer large enough to store the largest
+       objects.  yy::variant implements this buffer.  It was implemented with
+       Quentin Hocquet.
+       
+       * src/output.c (type_names_output): New.
+       (output_skeleton): Invoke it.
+       * data/c++.m4 (b4_variant_if): New.
+       (b4_symbol_value): If needed, provide a definition for variants.
+       * data/lalr1.cc (b4_symbol_value, b4_symbol_action_)
+       (b4_symbol_variant, _b4_char_sizeof_counter, _b4_char_sizeof_dummy)
+       (b4_char_sizeof, yy::variant): New.
+       (parser::parse): If variants are requested, define
+       parser::union_type, parser::variant, change the definition of
+       semantic_type, construct $$ before running the user action instead
+       of performing a default $$ = $1.
+       * examples/variant.yy: New.
+       Based on an example by Michiel De Wilde.
+
+2008-11-03  Akim Demaille  <demaille@gostai.com>
+
+       Parameterize the extraction of semantic values.
+       To make future changes easier, no longer rely on ".TYPE" being the
+       way to get a semantic value.
+       
+       * data/c.m4 (b4_symbol_value): New.
+       Use it.
+       * data/c++.m4, data/yacc.c: Use it.
+       * data/glr.c: Use b4_symbol_value.
+       (b4_rhs_data): New.
+       Use it.
+
+2008-11-03  Akim Demaille  <demaille@gostai.com>
+
+       Prepare easier M4 changes.
+       * data/lalr1.cc: Use escaped [] instead of literals to prepare
+       future changes.
+
+2008-11-02  Joel E. Denny  <jdenny@ces.clemson.edu>
+
+       Initiate further development.
+       * NEWS: Create an empty section for new entries.
+       * gnulib: Update submodule to HEAD.
+
+2008-11-02  Joel E. Denny  <jdenny@ces.clemson.edu>
+
+       * NEWS: Version 2.4.
+
+2008-11-02  Joel E. Denny  <jdenny@ces.clemson.edu>
+
+       Prepare for next release.
+       * NEWS: Briefly mention changes since 2.3b.
+       * README: Say GNU m4 1.4.6, which we've been requiring in release
+       announcements already, not 1.4.3, which breaks the build.
+
+2008-11-02  Joel E. Denny  <jdenny@ces.clemson.edu>
+
+       Say %language is experimental.
+       We're thinking of extending it's effect on output file naming.  See the
+       thread at
+       <http://lists.gnu.org/archive/html/bison-patches/2008-10/msg00003.html>.
+       * NEWS: Say it's experimental.
+       * doc/bison.texinfo (Decl Summary): Say it's experimental, and so don't
+       recommend it over %skeleton for now.
+       (Bison Options): Likewise.
+       (C++ Bison Interface): Use %skeleton not %language.
+       (Calc++ Parser): Use %skeleton not %language.
+       * src/getargs.c (usage): Say it's experimental.
+
 2008-11-01  Di-an Jan  <dianj@freeshell.org>
            Paolo Bonzini  <bonzini@gnu.org>