support cast function (#98)

* support cast function

Author: ZEXSM

README.md

@@ -24,6 +24,8 @@ Library for creating complex OData queries (OData version 4.01) based on data mo
         * [`indexof`](#indexof)
         * [`startswith`](#startswith)
         * [`length`](#length)
+    * type
+        * [`cast`](#cast)
   * sorting by several fields with indication of direction
 
 ## Installation
@@ -329,6 +331,15 @@ var constValue = 3;
 ```
 > $filter=length(ODataKind/ODataCode/Code) gt 0
 
+## Usage type functions
+
+#### <a name="cast"/> cast
+
+```csharp
+.Filter((s, f) => f.Contains(f.Cast(s.ODataKindNew.ODataCode.Code, "Edm.String"), "55"))
+```
+> $filter=contains(cast(ODataKindNew/ODataCode/Code,Edm.String),'55')
+
 ## Usage other functions
 
 #### ConvertEnumToString

src/OData.QueryBuilder/Conventions/Functions/IConvertFunction.cs

@@ -0,0 +1,36 @@
+using System;
+using System.Collections.Generic;
+
+namespace OData.QueryBuilder.Conventions.Functions
+{
+    /// <summary>
+    /// Custom functions
+    /// </summary>
+    public interface ICustomFunction
+    {
+        /// <summary>
+        /// Convert enum to string
+        /// </summary>
+        T ConvertEnumToString<T>(T value) where T : Enum;
+
+        /// <summary>
+        /// Convert datetime to string
+        /// </summary>
+        DateTime ConvertDateTimeToString(DateTime value, string format);
+
+        /// <summary>
+        /// Convert datetimeoffset to string
+        /// </summary>
+        DateTimeOffset ConvertDateTimeOffsetToString(DateTimeOffset value, string format);
+
+        /// <summary>
+        /// Replace characters
+        /// </summary>
+        string ReplaceCharacters(string value, IDictionary<string, string> keyValuePairs);
+
+        /// <summary>
+        /// Replace characters
+        /// </summary>
+        IEnumerable<string> ReplaceCharacters(IEnumerable<string> values, IDictionary<string, string> keyValuePairs);
+    }
+}

src/OData.QueryBuilder/Conventions/Functions/ICustomFunction.cs

@@ -2,7 +2,10 @@
 
 namespace OData.QueryBuilder.Conventions.Functions
 {
-    public interface IODataDateFunction
+    /// <summary>
+    /// https://docs.oasis-open.org/odata/odata/v4.01/odata-v4.01-part2-url-conventions.html#sec_DateandTimeFunctions
+    /// </summary>
+    public interface IODataDateTimeFunction
     {
         /// <summary>
         /// http://docs.oasis-open.org/odata/odata/v4.01/odata-v4.01-part2-url-conventions.html#sec_date

src/OData.QueryBuilder/Conventions/Functions/IODataDateFunction.cs

@@ -1,6 +1,9 @@
 namespace OData.QueryBuilder.Conventions.Functions
 {
-    public interface IODataFunction : IODataStringAndCollectionFunction, IODataDateFunction, IConvertFunction, IReplaceFunction
+    /// <summary>
+    /// OData functions
+    /// </summary>
+    public interface IODataFunction : IODataStringAndCollectionFunction, IODataDateTimeFunction, ICustomFunction, ITypeFunction
     {
     }
 }

src/OData.QueryBuilder/Conventions/Functions/IODataFunction.cs

@@ -40,6 +40,7 @@ public interface IODataStringAndCollectionFunction
 
         /// <summary>
         /// http://docs.oasis-open.org/odata/odata/v4.01/odata-v4.01-part2-url-conventions.html#sec_startswith
+        /// </summary>
         bool StartsWith(string columnName, string value);
 
         /// <summary>

src/OData.QueryBuilder/Conventions/Functions/IODataStringAndCollectionFunction.cs

@@ -1,9 +1,18 @@
 namespace OData.QueryBuilder.Conventions.Functions
 {
+    /// <summary>
+    /// Sort functions
+    /// </summary>
     public interface ISortFunction
     {
+        /// <summary>
+        /// Sort ascending
+        /// </summary>
         ISortFunction Ascending<T>(T column);
 
+        /// <summary>
+        /// Sort descending
+        /// </summary>
         ISortFunction Descending<T>(T column);
     }
 }

src/OData.QueryBuilder/Conventions/Functions/IReplaceFunction.cs

@@ -0,0 +1,16 @@
+namespace OData.QueryBuilder.Conventions.Functions
+{
+    /// <summary>
+    /// https://docs.oasis-open.org/odata/odata/v4.01/odata-v4.01-part2-url-conventions.html#sec_TypeFunctions
+    /// </summary>
+    public interface ITypeFunction
+    {
+        /// <summary>
+        /// https://docs.oasis-open.org/odata/odata/v4.01/odata-v4.01-part2-url-conventions.html#sec_cast
+        /// </summary>
+        /// <param name="columnName">Column name</param>
+        /// <param name="type">https://docs.microsoft.com/en-us/dotnet/framework/data/adonet/entity-data-model-primitive-data-types#primitive-data-types-supported-in-the-entity-data-model</param>
+        /// <returns></returns>
+        string Cast(string columnName, string type);
+    }
+}

src/OData.QueryBuilder/Conventions/Functions/ISortFunction.cs

@@ -74,7 +74,7 @@ protected virtual object GetValueOfMethodCallExpression(MethodCallExpression met
         {
             switch (methodCallExpression.Method.Name)
             {
-                case nameof(IReplaceFunction.ReplaceCharacters):
+                case nameof(ICustomFunction.ReplaceCharacters):
                     var @symbol0 = GetValue(methodCallExpression.Arguments[0]) as ICollection<string>;
                     var @symbol1 = GetValue(methodCallExpression.Arguments[1]) as IDictionary<string, string>;