private static Expression <TObject> Compose <TObject>(this Expression <TObject> firstExpression,
Expression <TObject> secondExpression, Func <Expression, Expression, Expression> mergeFunction)
{
var map = firstExpression.Parameters
.Select((first, i) => new { first, second = secondExpression.Parameters[i] })
.ToDictionary(p => p.second, p => p.first);
var secondExpressionBody = ParameterRebinder.Rebind(map, secondExpression.Body);
var newExpressionBody = mergeFunction(firstExpression.Body, secondExpressionBody);
return(Expression.Lambda <TObject>(newExpressionBody, firstExpression.Parameters));
}
