public void BinaryExpression_ConstantRight()
{
var left = Expression.Parameter(typeof(bool));
var right = Expression.Constant(true);
var binary = Expression.AndAlso(left, right);
var visitor = new PartialEvaluatingExpressionVisitor();
var result = visitor.Visit(binary);
Assert.AreEqual(binary, result);
}
public void Hashing()
{
var hasher = new HashingExpressionVisitor();
// No closure
Expression <Func <string> > expr1 = () => "hello".ToString().Substring(0, 1);
Expression <Func <string> > expr2 = () => "hello".ToString().Substring(0, 1);
hasher.Visit(expr1);
var hashCode1 = hasher.HashCode;
hasher.Reset();
hasher.Visit(expr2);
var hashCode2 = hasher.HashCode;
hasher.Reset();
Assert.AreNotEqual(expr1, expr2);
Assert.AreEqual(hashCode1, hashCode2);
// Closure
Expression <Func <string> > CreateExpressionWithClosure(int value)
{
Expression <Func <string> > expression = () => "hello".ToString().Substring(value, 1);
return(expression);
}
var expr3 = CreateExpressionWithClosure(0);
var expr4 = CreateExpressionWithClosure(1);
hasher.Visit(expr3);
var hashCode3 = hasher.HashCode;
hasher.Reset();
hasher.Visit(expr4);
var hashCode4 = hasher.HashCode;
hasher.Reset();
Assert.AreNotEqual(expr3, expr4);
Assert.AreEqual(hashCode3, hashCode4);
// Partially evaluated
var evaluator = new PartialEvaluatingExpressionVisitor();
Expression <Func <string> > expr5 = () => "hello".ToString().Substring(0, 1);
var expr6 = CreateExpressionWithClosure(0);
hasher.Visit(evaluator.Visit(expr5));
var hashCode5 = hasher.HashCode;
hasher.Reset();
hasher.Visit(evaluator.Visit(expr6));
var hashCode6 = hasher.HashCode;
hasher.Reset();
Assert.AreNotEqual(expr5, expr6);
Assert.AreEqual(hashCode5, hashCode6);
}
