diff --git a/doomsday/libdeng2/include/de/data/numbervalue.h b/doomsday/libdeng2/include/de/data/numbervalue.h
index 719b828059..180a2811c8 100644
--- a/doomsday/libdeng2/include/de/data/numbervalue.h
+++ b/doomsday/libdeng2/include/de/data/numbervalue.h
@@ -22,6 +22,8 @@
 
 #include "../Value"
 
+#include <QFlags>
+
 namespace de
 {
     /**
@@ -40,12 +42,18 @@ namespace de
         /// Truth values for logical operations. They are treated as
         /// number values.
         enum {
-            VALUE_FALSE = 0,
-            VALUE_TRUE = 1
+            False = 0,
+            True  = 1
+        };
+
+        enum SemanticHint {
+            Boolean = 0x1,      ///< The number is intended to be a boolean value.
+            DefaultSemantic = 0
         };
+        Q_DECLARE_FLAGS(SemanticHints, SemanticHint)
         
     public:
-        NumberValue(Number initialValue = 0);
+        NumberValue(Number initialValue = 0, SemanticHints semantic = DefaultSemantic);
 
         /**
          * Conversion template that forces a cast to another type.
@@ -71,7 +79,10 @@ namespace de
         
     private:
         Number _value;
+        SemanticHints _semantic;
     };
+
+    Q_DECLARE_OPERATORS_FOR_FLAGS(NumberValue::SemanticHints)
 }
 
 #endif /* LIBDENG2_NUMBERVALUE_H */
diff --git a/doomsday/libdeng2/src/data/numbervalue.cpp b/doomsday/libdeng2/src/data/numbervalue.cpp
index 25198d977c..7f344fac21 100644
--- a/doomsday/libdeng2/src/data/numbervalue.cpp
+++ b/doomsday/libdeng2/src/data/numbervalue.cpp
@@ -26,13 +26,13 @@
 
 using namespace de;
 
-NumberValue::NumberValue(Number initialValue)
-    : _value(initialValue) 
+NumberValue::NumberValue(Number initialValue, SemanticHints semantic)
+    : _value(initialValue), _semantic(semantic)
 {}
 
 Value *NumberValue::duplicate() const
 {
-    return new NumberValue(_value);
+    return new NumberValue(_value, _semantic);
 }
 
 Value::Number NumberValue::asNumber() const
@@ -44,7 +44,14 @@ Value::Text NumberValue::asText() const
 {
     Text result;
     QTextStream s(&result);
-    s << _value;
+    if(_semantic.testFlag(Boolean) && (_value == True || _value == False))
+    {
+        s << (isTrue()? "True" : "False");
+    }
+    else
+    {
+        s << _value;
+    }
     return result;
 }
 
@@ -128,9 +135,14 @@ void NumberValue::modulo(Value const &divisor)
     _value = int(_value) % int(other->_value);
 }
 
+// Flags for serialization:
+static duint8 const SEMANTIC_BOOLEAN = 0x01;
+
 void NumberValue::operator >> (Writer &to) const
 {
-    to << SerialId(NUMBER) << _value;
+    duint8 flags = (_semantic.testFlag(Boolean)? SEMANTIC_BOOLEAN : 0);
+
+    to << SerialId(NUMBER) << flags << _value;
 }
 
 void NumberValue::operator << (Reader &from)
@@ -143,5 +155,8 @@ void NumberValue::operator << (Reader &from)
         /// serialized value was invalid.
         throw DeserializationError("NumberValue::operator <<", "Invalid ID");
     }
-    from >> _value;
+    duint8 flags;
+    from >> flags >> _value;
+
+    _semantic = SemanticHints(flags & SEMANTIC_BOOLEAN? Boolean : 0);
 }
diff --git a/doomsday/libdeng2/src/scriptsys/constantexpression.cpp b/doomsday/libdeng2/src/scriptsys/constantexpression.cpp
index ed5060b6da..ce52f00f8a 100644
--- a/doomsday/libdeng2/src/scriptsys/constantexpression.cpp
+++ b/doomsday/libdeng2/src/scriptsys/constantexpression.cpp
@@ -50,12 +50,12 @@ ConstantExpression *ConstantExpression::None()
 
 ConstantExpression *ConstantExpression::True()
 {
-    return new ConstantExpression(new NumberValue(NumberValue::VALUE_TRUE));
+    return new ConstantExpression(new NumberValue(NumberValue::True, NumberValue::Boolean));
 }
 
 ConstantExpression *ConstantExpression::False()
 {
-    return new ConstantExpression(new NumberValue(NumberValue::VALUE_FALSE));
+    return new ConstantExpression(new NumberValue(NumberValue::False, NumberValue::Boolean));
 }
 
 ConstantExpression *ConstantExpression::Pi()
diff --git a/doomsday/libdeng2/src/scriptsys/operatorexpression.cpp b/doomsday/libdeng2/src/scriptsys/operatorexpression.cpp
index 76dff9f71c..900336b8a4 100644
--- a/doomsday/libdeng2/src/scriptsys/operatorexpression.cpp
+++ b/doomsday/libdeng2/src/scriptsys/operatorexpression.cpp
@@ -31,9 +31,6 @@
 
 using namespace de;
 
-#define HAS_LEFT_OPERAND    0x80
-#define OPERATOR_MASK       0x7f
-
 OperatorExpression::OperatorExpression() : _op(NONE), _leftOperand(0), _rightOperand(0)
 {}
 
@@ -86,7 +83,8 @@ void OperatorExpression::push(Evaluator &evaluator, Record *names) const
 
 Value *OperatorExpression::newBooleanValue(bool isTrue)
 {
-    return new NumberValue(isTrue? NumberValue::VALUE_TRUE : NumberValue::VALUE_FALSE);
+    return new NumberValue(isTrue? NumberValue::True : NumberValue::False,
+                           NumberValue::Boolean);
 }
 
 void OperatorExpression::verifyAssignable(Value *value)
@@ -256,6 +254,10 @@ Value *OperatorExpression::evaluate(Evaluator &evaluator) const
     return result;
 }
 
+// Flags for serialization:
+static duint8 const HAS_LEFT_OPERAND = 0x80;
+static duint8 const OPERATOR_MASK    = 0x7f;
+
 void OperatorExpression::operator >> (Writer &to) const
 {
     to << SerialId(OPERATOR);
diff --git a/doomsday/libdeng2/src/scriptsys/parser.cpp b/doomsday/libdeng2/src/scriptsys/parser.cpp
index e273bd121f..959f8e18a9 100644
--- a/doomsday/libdeng2/src/scriptsys/parser.cpp
+++ b/doomsday/libdeng2/src/scriptsys/parser.cpp
@@ -852,15 +852,15 @@ Expression *Parser::parseTokenExpression(TokenRange const &range, Expression::Fl
 Operator Parser::findLowestOperator(TokenRange const &range, TokenRange &leftSide, TokenRange &rightSide)
 {
     enum {
-        MAX_RANK            = 0x7fffffff,
-        RANK_MEMBER         = 13,
-        RANK_CALL           = 14,
-        RANK_INDEX          = 14,
-        RANK_SLICE          = 14,
-        RANK_DOT            = 15,
-        RANK_ARRAY          = MAX_RANK - 1,
-        RANK_DICTIONARY     = RANK_ARRAY,
-        RANK_PARENTHESIS    = MAX_RANK - 1
+        MAX_RANK         = 0x7fffffff,
+        RANK_MEMBER      = 13,
+        RANK_CALL        = 14,
+        RANK_INDEX       = 14,
+        RANK_SLICE       = 14,
+        RANK_DOT         = 15,
+        RANK_ARRAY       = MAX_RANK - 1,
+        RANK_DICTIONARY  = RANK_ARRAY,
+        RANK_PARENTHESIS = MAX_RANK - 1
     };
     enum Direction {
         LEFT_TO_RIGHT,