Abbasc52/optional fast compile (#570)

* added setting to turn off fast compilation

* added test cases and docs on ReSettings

* added ruleparameter.create method

* updated CHANGELOG

CHANGELOG.md

@@ -5,6 +5,8 @@ All notable changes to this project will be documented in this file.
 ## [5.0.3]
 - Updated dependencies to latest
 - Fixed RulesEngine throwing exception when type name is same as input name
+- Added config to disable FastCompile for expressions
+- Added RuleParameter.Create method for better handling on types when value is null
 
 ## [5.0.2]
 - Fixed Scoped Params returning incorrect results in some corner case scenarios

docs/index.md

@@ -37,6 +37,8 @@ RulesEngine is a highly extensible library to build rule based system using C# e
     - [Steps to use a custom Action](#steps-to-use-a-custom-action)
 - [Standalone Expression Evaluator](#standalone-expression-evaluator)
   - [Usage](#usage-2)
+- [Settings](#settings)
+  - [NestedRuleExecutionMode](#nestedruleexecutionmode)
 
 
 
@@ -555,3 +557,29 @@ This will output "Hello World"
 
 For more advanced usage, refer - https://dotnetfiddle.net/KSX8i0
 
+## Settings
+RulesEngine allows you to pass optional `ReSettings` in constructor to specify certain configuration for RulesEngine.
+
+Here are the all the options available:-
+
+
+| Property | Type | Default Value | Description |
+| --- | --- | --- | --- |
+| `CustomTypes` | `Type[]` | N/A | Custom types to be used in rule expressions. |
+| `CustomActions` | `Dictionary<string, Func<ActionBase>>` | N/A | Custom actions that can be used in the rules. |
+| `EnableExceptionAsErrorMessage` | `bool` | `true` | If `true`, returns any exception occurred while rule execution as an error message. Otherwise, throws an exception. This setting is only applicable if `IgnoreException` is set to `false`. |
+| `IgnoreException` | `bool` | `false` | If `true`, it will ignore any exception thrown with rule compilation/execution. |
+| `EnableFormattedErrorMessage` | `bool` | `true` | Enables error message formatting. |
+| `EnableScopedParams` | `bool` | `true` | Enables global parameters and local parameters for rules. |
+| `IsExpressionCaseSensitive` | `bool` | `false` | Sets whether expressions are case sensitive. |
+| `AutoRegisterInputType` | `bool` | `true` | Auto registers input type in custom type to allow calling method on type. |
+| `NestedRuleExecutionMode` | `NestedRuleExecutionMode` | `All` | Sets the mode for nested rule execution. |
+| `CacheConfig` | `MemCacheConfig` | N/A | Configures the memory cache. |
+| `UseFastExpressionCompiler` | `bool` | `true` | Whether to use FastExpressionCompiler for rule compilation. |
+
+
+### NestedRuleExecutionMode 
+| Value | Description |
+| --- | --- |
+| `All` | Executes all nested rules. |
+| `Performance` | Skips nested rules whose execution does not impact parent rule's result. |

src/RulesEngine/ExpressionBuilders/RuleExpressionParser.cs

@@ -57,10 +57,19 @@ namespace RulesEngine.ExpressionBuilders
             }
             var expressionBody = new List<Expression>() { e };
             var wrappedExpression = WrapExpression<T>(expressionBody, parameterExpressions, new ParameterExpression[] { });
-            return wrappedExpression.CompileFast();
+            return CompileExpression(wrappedExpression);
 
         }
 
+        private Func<object[], T> CompileExpression<T>(Expression<Func<object[], T>> expression)
+        {
+            if(_reSettings.UseFastExpressionCompiler)
+            {
+                return expression.CompileFast();
+            }
+            return expression.Compile();
+        }
+
         private Expression<Func<object[], T>> WrapExpression<T>(List<Expression> expressionList, ParameterExpression[] parameters, ParameterExpression[] variables)
         {
             var argExp = Expression.Parameter(typeof(object[]), "args");
@@ -77,7 +86,7 @@ namespace RulesEngine.ExpressionBuilders
         {
             ruleExpParams = ruleExpParams ?? new RuleExpressionParameter[] { };
             var expression = CreateDictionaryExpression(ruleParams, ruleExpParams);
-            return expression.CompileFast();
+            return CompileExpression(expression);
         }
 
         public T Evaluate<T>(string expression, RuleParameter[] ruleParams)

src/RulesEngine/Models/ReSettings.cs

@@ -27,7 +27,8 @@ namespace RulesEngine.Models
             CacheConfig = reSettings.CacheConfig;
             IsExpressionCaseSensitive = reSettings.IsExpressionCaseSensitive;
             AutoRegisterInputType = reSettings.AutoRegisterInputType;
-    }
+            UseFastExpressionCompiler = reSettings.UseFastExpressionCompiler;
+        }
 
 
         /// <summary>
@@ -79,6 +80,10 @@ namespace RulesEngine.Models
         /// </summary>
         public NestedRuleExecutionMode NestedRuleExecutionMode { get; set; } = NestedRuleExecutionMode.All;
         public MemCacheConfig CacheConfig { get; set; }
+        /// <summary>
+        /// Whether to use FastExpressionCompiler for rule compilation
+        /// </summary>
+        public bool UseFastExpressionCompiler { get; set; } = true;
     }
 
     public enum NestedRuleExecutionMode

src/RulesEngine/Models/RuleParameter.cs

@@ -17,10 +17,13 @@ namespace RulesEngine.Models
             Init(name, Value?.GetType());
         }
 
-        internal RuleParameter(string name, Type type)
+       
+        internal RuleParameter(string name, Type type,object value = null)
         {
+            Value = Utils.GetTypedObject(value);
             Init(name, type);
         }
+
         public Type Type { get; private set; }
         public string Name { get; private set; }
         public object Value { get; private set; }
@@ -33,5 +36,13 @@ namespace RulesEngine.Models
             ParameterExpression = Expression.Parameter(Type, Name);
         }
 
+        public static RuleParameter Create<T>(string name, T value)
+        {
+            var typedValue = Utils.GetTypedObject(value);
+            var type = typedValue?.GetType() ?? typeof(T);
+            return new RuleParameter(name,type,value);
+        }
+
+
     }
 }

test/RulesEngine.UnitTest/BusinessRuleEngineTest.cs

@@ -338,8 +338,9 @@ namespace RulesEngine.UnitTest
         }
 
         [Theory]
-        [InlineData("rules4.json")]
-        public async Task RulesEngine_Execute_Rule_For_Nested_Rule_Params_Returns_Success(string ruleFileName)
+        [InlineData("rules4.json", true)]
+        [InlineData("rules4.json", false)]
+        public async Task RulesEngine_Execute_Rule_For_Nested_Rule_Params_Returns_Success(string ruleFileName,bool fastExpressionEnabled)
         {
             var inputs = GetInputs4();
 
@@ -359,7 +360,9 @@ namespace RulesEngine.UnitTest
             }
 
             var fileData = File.ReadAllText(files[0]);
-            var bre = new RulesEngine(JsonConvert.DeserializeObject<Workflow[]>(fileData), null);
+            var bre = new RulesEngine(JsonConvert.DeserializeObject<Workflow[]>(fileData), new ReSettings {
+                UseFastExpressionCompiler = fastExpressionEnabled
+            });
             var result = await bre.ExecuteAllRulesAsync("inputWorkflow", ruleParams?.ToArray());
             var ruleResult = result?.FirstOrDefault(r => string.Equals(r.Rule.RuleName, "GiveDiscount10", StringComparison.OrdinalIgnoreCase));
             Assert.True(ruleResult.IsSuccess);

test/RulesEngine.UnitTest/RuleExpressionParserTests/RuleExpressionParserTests.cs

@@ -3,14 +3,8 @@
 
 using Newtonsoft.Json.Linq;
 using RulesEngine.ExpressionBuilders;
-using System;
-using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 using Xunit;
-using System.Text.Json;
 
 namespace RulesEngine.UnitTest.RuleExpressionParserTests
 {
@@ -59,5 +53,17 @@ namespace RulesEngine.UnitTest.RuleExpressionParserTests
 
             Assert.Equal("helloworld", value3);
         }
+
+        [Theory]
+        [InlineData(false)]
+        public void TestExpressionWithDifferentCompilerSettings(bool fastExpressionEnabled){
+            var ruleParser = new RuleExpressionParser(new Models.ReSettings() { UseFastExpressionCompiler = fastExpressionEnabled });
+
+            decimal? d1 = null;
+            var result = ruleParser.Evaluate<bool>("d1 < 20", new[] { Models.RuleParameter.Create("d1", d1) });
+            Assert.False(result);
+        }
     }
+
+    
 }