X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/b9278c7d174c1be5d7482343c5e433f428657ed0..fd003416d59cae9645d164b12495eb186efee848:/data/variant.hh

diff --git a/data/variant.hh b/data/variant.hh
index 65f0026e..91548d84 100644
--- a/data/variant.hh
+++ b/data/variant.hh
@@ -1,6 +1,6 @@
 # C++ skeleton for Bison
 
-# Copyright (C) 2002-2012 Free Software Foundation, Inc.
+# Copyright (C) 2002-2013 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -51,13 +51,6 @@ m4_define([_b4_char_sizeof_dummy],
 dummy[]_b4_char_sizeof_counter])
 
 
-# b4_char_sizeof_(SYMBOL-NUM)
-# ---------------------------
-# A comment describing this symbol.
-m4_define([b4_char_sizeof_],
-[      // b4_symbol([$1], [tag])
-])
-
 # b4_char_sizeof(SYMBOL-NUMS)
 # ---------------------------
 # To be mapped on the list of type names to produce:
@@ -69,108 +62,157 @@ m4_define([b4_char_sizeof_],
 m4_define([b4_char_sizeof],
 [b4_symbol_if([$1], [has_type],
 [
-m4_map([b4_char_sizeof_], [$@])dnl
+m4_map([      b4_symbol_tag_comment], [$@])dnl
       char _b4_char_sizeof_dummy@{sizeof([b4_symbol([$1], [type])])@};
 ])])
 
 
+# b4_variant_includes
+# -------------------
+# The needed includes for variants support.
+m4_define([b4_variant_includes],
+[b4_parse_assert_if([[#include <typeinfo>]])[
+#ifndef YYASSERT
+# include <cassert>
+# define YYASSERT assert
+#endif
+]])
+
 # b4_variant_define
 # -----------------
 # Define "variant".
 m4_define([b4_variant_define],
-[[
-  /// A char[S] buffer to store and retrieve objects.
+[[  /// A char[S] buffer to store and retrieve objects.
   ///
   /// Sort of a variant, but does not keep track of the nature
   /// of the stored data, since that knowledge is available
   /// via the current state.
   template <size_t S>
   struct variant
-  {]b4_parse_assert_if([
-    /// Whether something is contained.
-    bool built;
-])[
+  {
+    /// Type of *this.
+    typedef variant<S> self_type;
+
     /// Empty construction.
-    inline
     variant ()]b4_parse_assert_if([
-      : built (false)])[
+      : tname (YY_NULL)])[
     {}
 
-    /// Instantiate a \a T in here.
+    /// Construct and fill.
+    template <typename T>
+    variant (const T& t)]b4_parse_assert_if([
+      : tname (typeid (T).name ())])[
+    {
+      YYASSERT (sizeof (T) <= S);
+      new (buffer.raw) T (t);
+    }
+
+    /// Destruction, allowed only if empty.
+    ~variant ()
+    {]b4_parse_assert_if([
+      YYASSERT (!tname);
+    ])[}
+
+    /// Instantiate an empty \a T in here.
     template <typename T>
-    inline T&
+    T&
     build ()
     {]b4_parse_assert_if([
-      assert (!built);
-      built = true;])[
+      YYASSERT (!tname);
+      YYASSERT (sizeof (T) <= S);
+      tname = typeid (T).name ();])[
       return *new (buffer.raw) T;
     }
 
     /// Instantiate a \a T in here from \a t.
     template <typename T>
-    inline T&
+    T&
     build (const T& t)
     {]b4_parse_assert_if([
-      assert(!built);
-      built = true;])[
-      return *new (buffer.raw) T(t);
-    }
-
-    /// Construct and fill.
-    template <typename T>
-    inline
-    variant (const T& t)]b4_parse_assert_if([
-      : built (true)])[
-    {
-      new (buffer.raw) T(t);
+      YYASSERT (!tname);
+      YYASSERT (sizeof (T) <= S);
+      tname = typeid (T).name ();])[
+      return *new (buffer.raw) T (t);
     }
 
     /// Accessor to a built \a T.
     template <typename T>
-    inline T&
+    T&
     as ()
     {]b4_parse_assert_if([
-      assert (built);])[
-      return reinterpret_cast<T&>(buffer.raw);
+      YYASSERT (tname == typeid (T).name ());
+      YYASSERT (sizeof (T) <= S);])[
+      {
+        void *dummy = buffer.raw;
+        return *static_cast<T*> (dummy);
+      }
     }
 
     /// Const accessor to a built \a T (for %printer).
     template <typename T>
-    inline const T&
+    const T&
     as () const
     {]b4_parse_assert_if([
-      assert(built);])[
-      return reinterpret_cast<const T&>(buffer.raw);
+      YYASSERT (tname == typeid (T).name ());
+      YYASSERT (sizeof (T) <= S);])[
+      {
+        const void *dummy = buffer.raw;
+        return *static_cast<const T*> (dummy);
+      }
     }
 
-    /// Swap the content with \a other.
+    /// Swap the content with \a other, of same type.
+    ///
+    /// Both variants must be built beforehand, because swapping the actual
+    /// data requires reading it (with as()), and this is not possible on
+    /// unconstructed variants: it would require some dynamic testing, which
+    /// should not be the variant's responsability.
+    /// Swapping between built and (possibly) non-built is done with
+    /// variant::move ().
     template <typename T>
-    inline void
-    swap (variant<S>& other)
-    {
+    void
+    swap (self_type& other)
+    {]b4_parse_assert_if([
+      YYASSERT (tname);
+      YYASSERT (tname == other.tname);])[
       std::swap (as<T>(), other.as<T>());
     }
 
-    /// Assign the content of \a other to this.
+    /// Move the content of \a other to this.
+    ///
     /// Destroys \a other.
     template <typename T>
-    inline void
-    build (variant<S>& other)
-    {
+    void
+    move (self_type& other)
+    {]b4_parse_assert_if([
+      YYASSERT (!tname);])[
       build<T>();
       swap<T>(other);
       other.destroy<T>();
     }
 
+    /// Copy the content of \a other to this.
+    template <typename T>
+    void
+    copy (const self_type& other)
+    {
+      build<T> (other.as<T> ());
+    }
+
     /// Destroy the stored \a T.
     template <typename T>
-    inline void
+    void
     destroy ()
     {
-      as<T>().~T();]b4_parse_assert_if([
-      built = false;])[
+      as<T> ().~T ();]b4_parse_assert_if([
+      tname = YY_NULL;])[
     }
 
+  private:
+    /// Prohibit blind copies.
+    self_type& operator=(const self_type&);
+    variant (const self_type&);
+
     /// A buffer large enough to store any of the semantic values.
     /// Long double is chosen as it has the strongest alignment
     /// constraints.
@@ -178,7 +220,10 @@ m4_define([b4_variant_define],
     {
       long double align_me;
       char raw[S];
-    } buffer;
+    } buffer;]b4_parse_assert_if([
+
+    /// Whether the content is built: if defined, the name of the stored type.
+    const char *tname;])[
   };
 ]])
 
@@ -197,7 +242,8 @@ m4_define([b4_semantic_type_declare],
     {]b4_type_foreach([b4_char_sizeof])[};
 
     /// Symbol semantic values.
-    typedef variant<sizeof(union_type)> semantic_type;])
+    typedef variant<sizeof(union_type)> semantic_type;dnl
+])
 
 
 # How the semantic value is extracted when using variants.
@@ -264,11 +310,39 @@ b4_join(b4_symbol_if([$1], [has_type],
     return symbol_type (b4_join([token::b4_symbol([$1], [id])],
                                 b4_symbol_if([$1], [has_type], [v]),
                                 b4_locations_if([l])));
+
   }
 
 ])])])
 
 
+# b4_basic_symbol_constructor_declare
+# ----------------------------------
+# Generate a constructor declaration for basic_symbol from given type.
+m4_define([b4_basic_symbol_constructor_declare],
+[[
+  basic_symbol (]b4_join(
+          [typename Base::kind_type t],
+          b4_symbol_if([$1], [has_type], const b4_symbol([$1], [type])[ v]),
+          b4_locations_if([const location_type& l]))[);
+]])
+
+# b4_basic_symbol_constructor_define
+# ----------------------------------
+# Generate a constructor implementation for basic_symbol from given type.
+m4_define([b4_basic_symbol_constructor_define],
+[[
+  template <typename Base>
+  ]b4_parser_class_name[::basic_symbol<Base>::basic_symbol (]b4_join(
+          [typename Base::kind_type t],
+          b4_symbol_if([$1], [has_type], const b4_symbol([$1], [type])[ v]),
+          b4_locations_if([const location_type& l]))[)
+    : Base (t)
+    , value (]b4_symbol_if([$1], [has_type], [v])[)]b4_locations_if([
+    , location (l)])[
+  {}
+]])
+
 # b4_symbol_constructor_define
 # ----------------------------
 # Define the overloaded versions of make_symbol for all the value types.