Added explicit_bool type and cleaned up all the convert-to-booleans i…

…n this list

FabricSplice.h

@@ -1604,6 +1604,7 @@ Class Outline
 
 #include <stdint.h>
 #include <stdio.h>
+#include "explicit_bool.h"
 
 #if defined(_MSC_VER) || defined(SWIGWIN)
 # if defined(__cplusplus)
@@ -2350,10 +2351,10 @@ namespace FabricSplice
       }
 
       // bool conversion operator
-      operator bool() const
-      {
-        return isValid();
-      }
+	  operator explicit_bool::type() const
+	  {
+	    return explicit_bool::get(isValid());
+	  }
 
       // returns the index of this symbol
       unsigned int index() const
@@ -2511,9 +2512,9 @@ namespace FabricSplice
       }
 
       // bool conversion operator
-      operator bool() const
+      operator explicit_bool::type() const
       {
-        return isValid();
+        return explicit_bool::get(isValid());
       }
 
       // returns the symbol of this KLConstant
@@ -2593,11 +2594,11 @@ namespace FabricSplice
         return mRef != NULL;
       }
 
-      // bool conversion operator
-      operator bool() const
-      {
-        return isValid();
-      }
+	  // bool conversion operator
+	  operator explicit_bool::type() const
+	  {
+		  return explicit_bool::get(isValid());
+	  }
 
       // returns the symbol of this KLVariable
       KLSymbol symbol() const
@@ -2660,11 +2661,11 @@ namespace FabricSplice
         return mRef != NULL;
       }
 
-      // bool conversion operator
-      operator bool() const
-      {
-        return isValid();
-      }
+	  // bool conversion operator
+	  operator explicit_bool::type() const
+	  {
+		  return explicit_bool::get(isValid());
+	  }
 
       // returns the symbol of this KLStruct
       KLSymbol symbol() const
@@ -2777,11 +2778,11 @@ namespace FabricSplice
         return mRef != NULL;
       }
 
-      // bool conversion operator
-      operator bool() const
-      {
-        return isValid();
-      }
+	  // bool conversion operator
+	  operator explicit_bool::type() const
+	  {
+		  return explicit_bool::get(isValid());
+	  }
 
       // returns number of arguments in this KLArgumentList
       unsigned int nbArgs() const
@@ -2852,11 +2853,11 @@ namespace FabricSplice
         return mRef != NULL;
       }
 
-      // bool conversion operator
-      operator bool() const
-      {
-        return isValid();
-      }
+	  // bool conversion operator
+	  operator explicit_bool::type() const
+	  {
+		  return explicit_bool::get(isValid());
+	  }
 
       // returns the symbol of this KLOperator
       KLSymbol symbol() const
@@ -2959,11 +2960,11 @@ namespace FabricSplice
         return mRef != NULL;
       }
 
-      // bool conversion operator
-      operator bool() const
-      {
-        return isValid();
-      }
+	  // bool conversion operator
+	  operator explicit_bool::type() const
+	  {
+		  return explicit_bool::get(isValid());
+	  }
 
       // returns the symbol of this KLFunction
       KLSymbol symbol() const
@@ -3066,11 +3067,11 @@ namespace FabricSplice
         return mRef != NULL;
       }
 
-      // bool conversion operator
-      operator bool() const
-      {
-        return isValid();
-      }
+	  // bool conversion operator
+	  operator explicit_bool::type() const
+	  {
+		  return explicit_bool::get(isValid());
+	  }
 
       // returns the symbol of this KLInterface
       KLSymbol symbol() const
@@ -3161,10 +3162,10 @@ namespace FabricSplice
     }
 
     // bool conversion operator
-    operator bool() const
-    {
-      return isValid();
-    }
+	operator explicit_bool::type() const
+	{
+	  return explicit_bool::get(isValid());
+	}
 
     // returns the owner of the parser
     const char * owner() const 
@@ -3491,12 +3492,6 @@ namespace FabricSplice
     friend class DGGraph;
     friend class SceneManagement;
 
-	// Useful defines taken from 
-	// http://site.zorba.io/documentation/3.0/cxx/classzorba_1_1internal_1_1ztd_1_1explicit__bool.html
-	// to prevent converting this class to an int accidentally
-	typedef void (DGPort::*bool_type)() const;
-	void this_type_does_not_support_comparisons() const {}
-
   public:
 
     DGPort()
@@ -3533,9 +3528,9 @@ namespace FabricSplice
 	// bool conversion operator
 	// returning bool_type prevents the automatic
 	// conversion to int
-	operator bool_type() const
+	operator explicit_bool::type() const
 	{
-		return isValid() ? &DGPort::this_type_does_not_support_comparisons : 0;
+		return explicit_bool::get(isValid());
 	}
 
     // empties the content of the port
@@ -4008,10 +4003,10 @@ namespace FabricSplice
     }
 
     // bool conversion operator
-    operator bool() const
-    {
-      return isValid();
-    }
+	operator explicit_bool::type() const
+	{
+	  return explicit_bool::get(isValid());
+	}
 
     // empties the content of the graph
     void clear()

explicit_bool.h

@@ -0,0 +1,37 @@
+//
+// This template class allows for defining explicit boolean
+// version operators without C++0x
+//
+// This code is taken (mostly) verbatim from 
+// http://en.wikibooks.org/wiki/More_C%2B%2B_Idioms/Safe_bool
+// modified so the actual conversion operators is no hidden on the base class 
+//
+// Usage is like so
+//
+//
+//  class YourClass : 
+//    public safe_bool <YourClass> // CRTP idiom
+//  {
+//  public:
+//    // Define boolean conversion
+//    operator explicit_bool::type() const {
+//      return explicit_bool::get(SomeLogicHere()); 
+//    }
+//  };
+//
+//   This will allow
+// if (yourClass)
+//   but not
+// int var = yourClass;
+
+#pragma once
+
+class explicit_bool {
+  public:
+    typedef void (explicit_bool::*type)() const;
+    void this_type_does_not_support_comparisons() const {}
+
+    static type get(bool condition) {
+        return condition ? &explicit_bool::this_type_does_not_support_comparisons : 0;
+    }
+};