Add 'np(...)' Null Propagating function (#223)

* GenerateAndAlsoMemberExpression

* tests

* refactor

* 1.0.10

* update test

* UserShares

Author: StefH

Directory.Build.props

@@ -4,7 +4,7 @@
   </PropertyGroup>
 
   <PropertyGroup>
-    <VersionPrefix>1.0.9.2</VersionPrefix>
+    <VersionPrefix>1.0.10</VersionPrefix>
   </PropertyGroup>
 
   <Choose>

src-console/ConsoleAppEF2.0.2_InMemory/Program.cs

@@ -11,6 +11,16 @@ namespace ConsoleAppEF2
 {
     class Program
     {
+        class User
+        {
+            public string Name { get; set; }
+
+            public string GetDisplayName(bool a, bool b, bool c)
+            {
+                return Name + "GetDisplayName";
+            }
+        }
+
         class C : AbstractDynamicLinqCustomTypeProvider, IDynamicLinkCustomTypeProvider
         {
             public HashSet<Type> GetCustomTypes()
@@ -69,6 +79,15 @@ static void Main(string[] args)
             };
             Console.WriteLine("all {0}", JsonConvert.SerializeObject(all, Formatting.Indented));
 
+            var projects = new[]
+            {
+                new { UserShares = new [] { new User { Name  = "John" } } }
+            }.AsQueryable();
+
+            var filter = "UserShares.Any(GetDisplayName(true,true,false).Contains(\"John\"))";
+            var filtered = projects.Where(filter);
+            Console.WriteLine("filtered {0}", JsonConvert.SerializeObject(filtered, Formatting.Indented));
+
             var config = new ParsingConfig
             {
                 CustomTypeProvider = new C()
@@ -83,6 +102,9 @@ static void Main(string[] args)
             context.Cars.Add(new Car { Brand = "Alfa", Color = "Black", Vin = "a%bc", Year = "1979", DateLastModified = dateLastModified.AddDays(3) });
             context.SaveChanges();
 
+            var methodTest = context.Cars.Select("it.X(true, \"tst\").Contains(\"Blue\")");
+            Console.WriteLine("methodTest {0}", JsonConvert.SerializeObject(methodTest, Formatting.Indented));
+
             var carSingleOrDefault = context.Cars.SingleOrDefault(config, "Brand = \"Ford\"");
             Console.WriteLine("carSingleOrDefault {0}", JsonConvert.SerializeObject(carSingleOrDefault, Formatting.Indented));
 

src-console/ConsoleAppEF2.0/Database/Car.cs

@@ -23,5 +23,10 @@ public class Car
 
         [Required]
         public DateTime DateLastModified { get; set; }
+
+        public string X(bool b, string s)
+        {
+            return b + s + Color;
+        }
     }
 }

src-console/ConsoleAppEF2.1.1_InMemory/Program.cs

@@ -7,7 +7,6 @@
 using System.Reflection;
 using ConsoleAppEF2.Database;
 using Newtonsoft.Json;
-using Newtonsoft.Json.Linq;
 
 namespace ConsoleAppEF2
 {
@@ -18,11 +17,17 @@ public class NestedDto
             public string Name { get; set; }
 
             public NestedDto2 NestedDto2 { get; set; }
+        }
 
+        public class NestedDto2
+        {
+            public string Name2 { get; set; }
 
+            public int Id { get; set; }
+            public NestedDto3 NestedDto3 { get; set; }
         }
 
-        public class NestedDto2
+        public class NestedDto3
         {
             public string Name2 { get; set; }
 
@@ -50,129 +55,18 @@ public Type ResolveType(string typeName)
             }
         }
 
-        private static object GetObj()
-        {
-            return new
-            {
-                Id = 5,
-                Value = 400
-            };
-        }
-
-        class X : DynamicClass
-        {
-
-        }
-
-        private static IQueryable GetQueryable()
-        {
-            var random = new Random((int)DateTime.Now.Ticks);
-
-            var jt = typeof(JToken);
-
-            var em = jt.GetTypeInfo().GetDeclaredMethods("op_Explicit");
-            var im = jt.GetTypeInfo().GetDeclaredMethods("op_Explicit");
-
-            var j = new JObject
-            {
-                { "Id", new JValue(9) },
-                { "Name", new JValue("Test") }
-            };
-
-            //(j["Id"] as JValue).Value
-
-            IQueryable jarray = new[] { j }.AsQueryable();
-            var jresult = jarray.Select("new (int(Id) as Id, string(Name) as Name)");
-
-            var an = jresult.Any("Id > 4");
-
-
-            var dx = new X();
-            dx["Id"] = 5;
-
-            IQueryable srcDX = new[] { dx }.AsQueryable();
-            var b = srcDX.Select("new (Id.ToString() as Id)");
-            var anyDX = b.Any("int.Parse(Id) > 4");
-
-            var x = Enumerable.Range(0, 10).Select(i => new
-            {
-                Id = i,
-                Value = random.Next()
-            }).AsQueryable();
-
-            //var any = x.Any("Id > 4");
-
-            //var obj = new
-            //{
-            //    Id = 5,
-            //    Value = random.Next()
-            //};
-            //var x2 = Enumerable.Range(0, 1).Select(_ => obj).AsQueryable();
-            //var any2 = x.Any("Id > 4");
-
-            //var o = GetObj();
-            //var t = o.GetType();
-            //IQueryable source = new[] { o }.AsQueryable();
-            //// source.ElementType = t;
-
-            //var x2b = new[] { o }.AsQueryable();
-            //var any2function = x2b.Any(null, "Id > 4", t);
-
-            //var any2b = x2b.Any("Id > 4");
-
-            //var x3 = new[] { obj }.AsQueryable();
-            //var any3 = x3.Any("Id > 4");
-
-            return x.Select("new (it as Id, @0 as Value)", random.Next());
-            // return x.AsQueryable(); //x.AsQueryable().Select("new (Id, Value)");
-        }
-
-        public static IQueryable Transform(this IQueryable source, Type resultType)
+        static void Main(string[] args)
         {
-            var resultProperties = resultType.GetProperties().Where(p => p.CanWrite);
+            var q = new[] { new NestedDto(), new NestedDto { NestedDto2 = new NestedDto2 { NestedDto3 = new NestedDto3 { Id = 42 } } } }.AsQueryable();
 
-            ParameterExpression s = Expression.Parameter(source.ElementType, "s");
+            var np1 = q.Select("np(it.NestedDto2.NestedDto3.Id, 0)");
+            var npResult1 = np1.ToDynamicList<int>();
+            Console.WriteLine("npResult1 {0}", JsonConvert.SerializeObject(npResult1, Formatting.Indented));
 
-            var memberBindings =
-                resultProperties.Select(p =>
-                    Expression.Bind(resultType.GetMember(p.Name)[0], Expression.Property(s, p.Name))).OfType<MemberBinding>();
+            var np2 = q.Select("np(it.NestedDto2.NestedDto3.Id)");
+            var npResult2 = np2.ToDynamicList<int?>();
+            Console.WriteLine("npResult2 {0}", JsonConvert.SerializeObject(npResult2, Formatting.Indented));
 
-            Expression memberInit = Expression.MemberInit(
-                Expression.New(resultType),
-                memberBindings
-            );
-
-            var memberInitLambda = Expression.Lambda(memberInit, s);
-
-            var typeArgs = new[]
-            {
-                source.ElementType,
-                memberInit.Type
-            };
-
-            var mc = Expression.Call(typeof(Queryable), "Select", typeArgs, source.Expression, memberInitLambda);
-
-            var query = source.Provider.CreateQuery(mc);
-
-            return query;
-        }
-
-        public static IQueryable<T> EmptyQueryByExample<T>(this T _) => Enumerable.Empty<T>().AsQueryable();
-
-
-        private static TResult Execute<TResult>(MethodInfo operatorMethodInfo, IQueryable source, Expression expression, Type t = null)
-        {
-            operatorMethodInfo = operatorMethodInfo.GetGenericArguments().Length == 2
-                ? operatorMethodInfo.MakeGenericMethod(t == null ? source.ElementType : t, typeof(TResult))
-                : operatorMethodInfo.MakeGenericMethod(t == null ? source.ElementType : t);
-
-            var optimized = Expression.Call(null, operatorMethodInfo, source.Expression, expression);
-            return source.Provider.Execute<TResult>(optimized);
-        }
-
-        static void Main(string[] args)
-        {
-            var q = new[] { new NestedDto(), new NestedDto { NestedDto2 = new NestedDto2 { Id = 42 } } }.AsQueryable();
             var r1 = q.Select("it != null && it.NestedDto2 != null ? it.NestedDto2.Id : null");
             var list1 = r1.ToDynamicList<int?>();
 
@@ -191,18 +85,6 @@ static void Main(string[] args)
             Console.WriteLine(projectedData.First().Name);
             Console.WriteLine(projectedData.Last().Name);
 
-            IQueryable qry = GetQueryable();
-
-            var result = qry.Select("it").OrderBy("Value");
-            try
-            {
-                Console.WriteLine("result {0}", JsonConvert.SerializeObject(result, Formatting.Indented));
-            }
-            catch (Exception)
-            {
-                // Console.WriteLine(e);
-            }
-
             var all = new
             {
                 test1 = new List<int> { 1, 2, 3 }.ToDynamicList(typeof(int)),

src/System.Linq.Dynamic.Core/Parser/ExpressionHelper.cs

@@ -1,4 +1,5 @@
 using JetBrains.Annotations;
+using System.Collections.Generic;
 using System.Globalization;
 using System.Linq.Dynamic.Core.Validation;
 using System.Linq.Expressions;
@@ -234,5 +235,79 @@ private void WrapConstantExpressions(ref Expression left, ref Expression right)
                 _constantExpressionWrapper.Wrap(ref right);
             }
         }
+
+        public Expression GenerateAndAlsoNotNullExpression(Expression sourceExpression)
+        {
+            var expresssions = CollectExpressions(sourceExpression);
+            if (!expresssions.Any())
+            {
+                return null;
+            }
+
+            // Reverse the list
+            expresssions.Reverse();
+
+            // Convert all expressions into '!= null'
+            var binaryExpressions = expresssions.Select(expression => Expression.NotEqual(expression, Constants.NullLiteral)).ToArray();
+
+            // Convert all binary expressions into `AndAlso(...)`
+            var andAlsoExpression = binaryExpressions[0];
+            for (int i = 1; i < binaryExpressions.Length; i++)
+            {
+                andAlsoExpression = Expression.AndAlso(andAlsoExpression, binaryExpressions[i]);
+            }
+
+            return andAlsoExpression;
+        }
+
+        private static Expression GetMemberExpression(Expression expression)
+        {
+            if (expression is ParameterExpression parameterExpression)
+            {
+                return parameterExpression;
+            }
+
+            if (expression is MemberExpression memberExpression)
+            {
+                return memberExpression;
+            }
+
+            if (expression is LambdaExpression lambdaExpression)
+            {
+                if (lambdaExpression.Body is MemberExpression bodyAsMemberExpression)
+                {
+                    return bodyAsMemberExpression;
+                }
+
+                if (lambdaExpression.Body is UnaryExpression bodyAsunaryExpression)
+                {
+                    return bodyAsunaryExpression.Operand;
+                }
+            }
+
+            return null;
+        }
+
+        private static List<Expression> CollectExpressions(Expression sourceExpression)
+        {
+            var list = new List<Expression>();
+            Expression expression = GetMemberExpression(sourceExpression);
+
+            while (expression is MemberExpression memberExpression)
+            {
+                expression = GetMemberExpression(memberExpression.Expression);
+                if (expression is MemberExpression)
+                {
+                    list.Add(expression);
+                }
+            }
+
+            if (expression is ParameterExpression)
+            {
+                list.Add(expression);
+            }
+
+            return list;
+        }
     }
 }