X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/733fb7c593486846eca5a60d1e3ff6880ce358d7..66c209cf435b5bfc5cf982d8df9cc3ef05b4546b:/data/variant.hh?ds=sidebyside

diff --git a/data/variant.hh b/data/variant.hh
index 1b033886..91548d84 100644
--- a/data/variant.hh
+++ b/data/variant.hh
@@ -72,7 +72,6 @@ m4_map([      b4_symbol_tag_comment], [$@])dnl
 # The needed includes for variants support.
 m4_define([b4_variant_includes],
 [b4_parse_assert_if([[#include <typeinfo>]])[
-#include <cstdlib>  // abort
 #ifndef YYASSERT
 # include <cassert>
 # define YYASSERT assert
@@ -96,19 +95,31 @@ m4_define([b4_variant_define],
 
     /// Empty construction.
     variant ()]b4_parse_assert_if([
-      : built (false)
-      , tname (YY_NULL)])[
+      : 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>
     T&
     build ()
     {]b4_parse_assert_if([
-      //YYASSERT (!built);
-      //YYASSERT (!tname);
+      YYASSERT (!tname);
       YYASSERT (sizeof (T) <= S);
-      built = true;
       tname = typeid (T).name ();])[
       return *new (buffer.raw) T;
     }
@@ -118,33 +129,23 @@ m4_define([b4_variant_define],
     T&
     build (const T& t)
     {]b4_parse_assert_if([
-      //YYASSERT (!built);
-      //YYASSERT (!tname);
+      YYASSERT (!tname);
       YYASSERT (sizeof (T) <= S);
-      built = true;
       tname = typeid (T).name ();])[
       return *new (buffer.raw) T (t);
     }
 
-    /// Construct and fill.
-    template <typename T>
-    variant (const T& t)]b4_parse_assert_if([
-      : built (true)
-      , tname (typeid (T).name ())])[
-    {
-      YYASSERT (sizeof (T) <= S);
-      new (buffer.raw) T (t);
-    }
-
     /// Accessor to a built \a T.
     template <typename T>
     T&
     as ()
     {]b4_parse_assert_if([
-      YYASSERT (built);
       YYASSERT (tname == typeid (T).name ());
       YYASSERT (sizeof (T) <= S);])[
-      return reinterpret_cast<T&> (buffer.raw);
+      {
+        void *dummy = buffer.raw;
+        return *static_cast<T*> (dummy);
+      }
     }
 
     /// Const accessor to a built \a T (for %printer).
@@ -152,46 +153,48 @@ m4_define([b4_variant_define],
     const T&
     as () const
     {]b4_parse_assert_if([
-      YYASSERT (built);
       YYASSERT (tname == typeid (T).name ());
       YYASSERT (sizeof (T) <= S);])[
-      return reinterpret_cast<const T&> (buffer.raw);
+      {
+        const void *dummy = buffer.raw;
+        return *static_cast<const T*> (dummy);
+      }
     }
 
     /// 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
+    /// Swapping between built and (possibly) non-built is done with
     /// variant::move ().
     template <typename T>
     void
-    swap (variant<S>& other)
+    swap (self_type& other)
     {]b4_parse_assert_if([
-      YYASSERT (built);
-      YYASSERT (other.built);
+      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>
     void
-    move (variant<S>& other)
+    move (self_type& other)
     {]b4_parse_assert_if([
-      YYASSERT (! built);])[
+      YYASSERT (!tname);])[
       build<T>();
       swap<T>(other);
       other.destroy<T>();
     }
 
     /// Copy the content of \a other to this.
-    /// Destroys \a other.
     template <typename T>
     void
-    copy (const variant<S>& other)
+    copy (const self_type& other)
     {
       build<T> (other.as<T> ());
     }
@@ -202,23 +205,14 @@ m4_define([b4_variant_define],
     destroy ()
     {
       as<T> ().~T ();]b4_parse_assert_if([
-      built = false;
       tname = YY_NULL;])[
     }
 
+  private:
     /// Prohibit blind copies.
-    private:
-    self_type& operator=(const self_type&)
-    {
-      abort ();
-    }
-
-    variant (const self_type&)
-    {
-      abort ();
-    }
+    self_type& operator=(const self_type&);
+    variant (const self_type&);
 
-  private:
     /// A buffer large enough to store any of the semantic values.
     /// Long double is chosen as it has the strongest alignment
     /// constraints.
@@ -227,10 +221,9 @@ m4_define([b4_variant_define],
       long double align_me;
       char raw[S];
     } buffer;]b4_parse_assert_if([
-    /// Whether something is contained.
-    bool built;
-    /// If defined, the name of the stored type.
-    const char* tname;])[
+
+    /// Whether the content is built: if defined, the name of the stored type.
+    const char *tname;])[
   };
 ]])
 
@@ -317,11 +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.