Add "%define assert" to variants.

[bison.git] / data / lalr1-fusion.cc

diff --git a/data/lalr1-fusion.cc b/data/lalr1-fusion.cc
index bae0c49e64f10ae0fe555aa3afb2173fa71c66da..1f1129ae8a4ea4200127924adbec16a2ef539325 100644 (file)
--- a/data/lalr1-fusion.cc
+++ b/data/lalr1-fusion.cc
@@ -40,6 +40,12 @@ b4_variant_if([
 ]) # b4_variant_if
 
 
+# b4_assert_if([IF-ASSERTIONS-ARE-USED], [IF-NOT])
+# ----------------------------------------------------
+m4_define([b4_assert_if],
+[b4_percent_define_ifdef([[assert]], [$1], [$2])])
+
+
 # b4_rhs_value(RULE-LENGTH, NUM, [TYPE])
 # --------------------------------------
 # Expansion of $<TYPE>NUM, where the current rule has RULE-LENGTH
@@ -85,13 +91,13 @@ m4_define([b4_symbol_action_],
 ])])
 
 
-# b4_symbol_variant(YYTYPE, YYVAL, ACTION)
-# ----------------------------------------
+# b4_symbol_variant(YYTYPE, YYVAL, ACTION, [ARGS])
+# ------------------------------------------------
 # Run some ACTION ("build", or "destroy") on YYVAL of symbol type
 # YYTYPE.
 m4_define([b4_symbol_variant],
 [m4_pushdef([b4_dollar_dollar],
-            [$2.$3<$][3>()])dnl
+            [$2.$3<$][3>(m4_shift3($@))])dnl
   switch ($1)
     {
 m4_map([b4_symbol_action_], m4_defn([b4_type_names]))
@@ -161,6 +167,7 @@ dnl FIXME: This is wrong, we want computed header guards.
 
 ]b4_percent_code_get([[requires]])[
 
+]b4_assert_if([#include <cassert>])[
 #include <string>
 #include <iostream>
 #include "stack.hh"
@@ -177,28 +184,31 @@ dnl FIXME: This is wrong, we want computed header guards.
   /// via the current state.
   template <size_t S>
   struct variant
-  {
+  {]b4_assert_if([
+    /// Whether something is contained.
+    bool built;
+
+    /// Initially uninitialized.
+    variant ()
+      : built(false)
+    {}])[
+
     /// Instantiate a \a T in here.
     template <typename T>
     inline T&
     build()
-    {
+    {]b4_assert_if([
+      assert(!built);
+      built = true;])[
       return *new (buffer) T;
     }
 
-    /// Destroy the stored \a T.
-    template <typename T>
-    inline void
-    destroy()
-    {
-      reinterpret_cast<T&>(buffer).~T();
-    }
-
     /// Accessor to a built \a T.
     template <typename T>
     inline T&
     as()
-    {
+    {]b4_assert_if([
+      assert(built);])[
       return reinterpret_cast<T&>(buffer);
     }
 
@@ -206,10 +216,39 @@ dnl FIXME: This is wrong, we want computed header guards.
     template <typename T>
     inline const T&
     as() const
-    {
+    {]b4_assert_if([
+      assert(built);])[
       return reinterpret_cast<const T&>(buffer);
     }
 
+    /// Swap the content with \a other.
+    template <typename T>
+    inline void
+    swap(variant<S>& other)
+    {
+      std::swap(as<T>(), other.as<T>());
+    }
+
+    /// Assign the content of \a other to this.
+    /// Destroys \a other.
+    template <typename T>
+    inline void
+    build(variant<S>& other)
+    {
+      build<T>();
+      swap<T>(other);
+      other.destroy<T>();
+    }
+
+    /// Destroy the stored \a T.
+    template <typename T>
+    inline void
+    destroy()
+    {
+      as<T>().~T();]b4_assert_if([
+      built = false;])[
+    }
+
     /// A buffer large enough to store any of the semantic values.
     char buffer[S];
   };
@@ -520,26 +559,26 @@ b4_percent_code_get[]dnl
 # define YYCDEBUG if (yydebug_) (*yycdebug_)
 
 # define YY_SYMBOL_PRINT(Title, Type, Value, Location) \
-do {                                                   \
-  if (yydebug_)                                                \
+  do {                                                 \
+    if (yydebug_)                                       \
     {                                                  \
       *yycdebug_ << Title << ' ';                      \
       yy_symbol_print_ ((Type), (Value), (Location));  \
       *yycdebug_ << std::endl;                         \
     }                                                  \
-} while (false)
+  } while (false)
 
 # define YY_REDUCE_PRINT(Rule)         \
-do {                                   \
-  if (yydebug_)                                \
-    yy_reduce_print_ (Rule);           \
-} while (false)
+  do {                                 \
+    if (yydebug_)                       \
+      yy_reduce_print_ (Rule);         \
+  } while (false)
 
 # define YY_STACK_PRINT()              \
-do {                                   \
-  if (yydebug_)                                \
-    yystack_print_ ();                 \
-} while (false)
+  do {                                 \
+    if (yydebug_)                       \
+      yystack_print_ ();                \
+  } while (false)
 
 #else /* !YYDEBUG */
 
@@ -683,7 +722,10 @@ do {                                       \
   ]b4_parser_class_name[::yypush_ (state_type s,
                            semantic_type& v, const location_type& l)
   {
-    yystack_.push (data_type (s, v, l));
+]b4_variant_if(
+[[    yystack_.push (data_type (s, semantic_type(), l));
+    ]b4_symbol_variant([[yystos_[s]]], [[yystack_[0].value]], [build], [v])],
+[    yystack_.push (data_type (s, v, l));])[
   }
 
   void
@@ -928,9 +970,9 @@ m4_ifdef([b4_lex_param], [, ]b4_lex_param))[;
 
        if (yychar <= yyeof_)
          {
-         /* Return failure if at end of input.  */
-         if (yychar == yyeof_)
-           YYABORT;
+            /* Return failure if at end of input.  */
+            if (yychar == yyeof_)
+              YYABORT;
          }
        else
          {