public static Expression FoldConditional(ConditionalExpression inputExpression)
{
Expression test = ConstantFolding.Fold(inputExpression.Test);
Expression ifTrue = ConstantFolding.Fold(inputExpression.IfTrue);
Expression ifFalse = ConstantFolding.Fold(inputExpression.IfFalse);
Expression resultExpression;
if (test != inputExpression.Test || ifTrue != inputExpression.IfTrue || ifFalse != inputExpression.IfFalse)
{
resultExpression = Expression.Condition(test, ifTrue, ifFalse);
}
else
{
resultExpression = inputExpression;
}
if (IsConstant(test))
{
object value = ExpressionSimplifier.Evaluate(test);
bool bValue = (bool)value;
if (bValue)
{
// ifTrue is already folded
resultExpression = ifTrue;
}
else
{
resultExpression = ifFalse;
}
}
return(resultExpression);
}
public static Expression FoldInvocation(InvocationExpression inputExpression)
{
IEnumerable <Expression> args = ConstantFolding.FoldExpressionList(inputExpression.Arguments);
Expression expr = ConstantFolding.Fold(inputExpression.Expression);
Expression resultExpression;
if (args != inputExpression.Arguments || expr != inputExpression.Expression)
{
resultExpression = Expression.Invoke(expr, args);
}
else
{
resultExpression = inputExpression;
}
#if zero
if (!IsConstant(expr))
{
return(retval);
}
// lambdas are constant
#endif
foreach (Expression arg in args)
{
if (!IsConstant(arg))
{
return(resultExpression);
}
}
resultExpression = ExpressionSimplifier.EvaluateToExpression(resultExpression);
return(resultExpression);
}
public static Expression FoldBinary(BinaryExpression inputExpression)
{
Expression left = ConstantFolding.Fold(inputExpression.Left);
Expression right = ConstantFolding.Fold(inputExpression.Right);
LambdaExpression conversion = ConstantFolding.FoldLambda(inputExpression.Conversion);
Expression resultExpression;
if (left != inputExpression.Left || right != inputExpression.Right || conversion != inputExpression.Conversion)
{
if (inputExpression.NodeType == ExpressionType.Coalesce)
{
resultExpression = Expression.Coalesce(left, right, conversion);
}
else
{
resultExpression = Expression.MakeBinary(inputExpression.NodeType, left, right, inputExpression.IsLiftedToNull, inputExpression.Method);
}
}
else
{
resultExpression = inputExpression;
}
if (IsConstant(left) && inputExpression.NodeType == ExpressionType.Coalesce)
{
object leftValue = ExpressionSimplifier.Evaluate(left);
if (leftValue == null)
{
resultExpression = right;
}
else
{
resultExpression = Expression.Constant(leftValue);
}
}
else if (IsConstant(left) && IsConstant(right))
{
resultExpression = ExpressionSimplifier.EvaluateToExpression(resultExpression);
}
return(resultExpression);
}
public static Expression FoldMemberAccess(MemberExpression inputExpression)
{
Expression expr = ConstantFolding.Fold(inputExpression.Expression);
Expression resultExpression;
if (expr != inputExpression.Expression)
{
resultExpression = Expression.MakeMemberAccess(expr, inputExpression.Member);
}
else
{
resultExpression = inputExpression;
}
if (IsConstant(expr))
{
resultExpression = ExpressionSimplifier.EvaluateToExpression(resultExpression);
}
return(resultExpression);
}
public static Expression FoldTypeIs(TypeBinaryExpression inputExpression)
{
Expression expr = ConstantFolding.Fold(inputExpression.Expression);
Expression resultExpression;
if (expr != inputExpression.Expression)
{
resultExpression = Expression.TypeIs(expr, inputExpression.TypeOperand);
}
else
{
resultExpression = inputExpression;
}
if (IsConstant(expr))
{
resultExpression = ExpressionSimplifier.EvaluateToExpression(resultExpression);
}
return(resultExpression);
}
public static Expression FoldUnary(UnaryExpression inputExpression)
{
Expression operand = ConstantFolding.Fold(inputExpression.Operand);
Expression resultExpression;
if (operand != inputExpression.Operand)
{
resultExpression = Expression.MakeUnary(inputExpression.NodeType, operand, inputExpression.Type, inputExpression.Method);
}
else
{
resultExpression = inputExpression;
}
if (IsConstant(operand))
{
resultExpression = ExpressionSimplifier.EvaluateToExpression(resultExpression);
}
return(resultExpression);
}
public static Expression FoldMethodCall(MethodCallExpression inputExpression)
{
Expression obj = ConstantFolding.Fold(inputExpression.Object);
ReadOnlyCollection <Expression> args = ConstantFolding.FoldExpressionList(inputExpression.Arguments);
Expression resultExpression;
if (obj != inputExpression.Object || args != inputExpression.Arguments)
{
resultExpression = Expression.Call(obj, inputExpression.Method, args);
}
else
{
resultExpression = inputExpression;
}
if (!IsConstant(obj))
{
return(resultExpression);
}
foreach (Expression arg in args)
{
if (!IsConstant(arg))
{
return(resultExpression);
}
}
// skip simplifying .Take(Constant)
if (inputExpression.Method.IsStatic &&
inputExpression.Method.DeclaringType.IsAssignableFrom(typeof(Queryable)) &&
inputExpression.Method.Name.Equals("Take"))
{
return(resultExpression);
}
resultExpression = ExpressionSimplifier.EvaluateToExpression(resultExpression);
return(resultExpression);
}