Standard constants (variables)

Custom variables

ExpressionEvaluatorevaluator=newExpressionEvaluator();evaluator.Variables=newDictionary<string,object>(){{"x",2.5},{"y",-3.6},{"myVar","Hello World"},{"myArray",newobject[]{3.5,"Test",false}},};

x+y-1.1myVar + " !!!"Hello World !!!myArray.Length3myArray[0]3.5myArray[1].Length4myArray[2] || trueTrue

ExpressionEvaluatorevaluator=newExpressionEvaluator();evaluator.Variables=newDictionary<string,object>(){{"Add",newFunc<int,int,int>((x,y)=>x+y)},{"SayHelloTo",newAction<string>(name=>Console.WriteLine($"Hello{name} !!!"))},};

Add(5, 9)14SayHelloTo("John")Hello John !!!{null}

SubExpression variable

ExpressionEvaluatorevaluator=newExpressionEvaluator();evaluator.Variables["a"]=1;evaluator.Variables["b"]=2;evaluator.Variables["c"]=newSubExpression("a+b");evaluator.Variables["d"]=newSubExpression("c+3");evaluator.Variables["e"]="c+3";

a1b2c3d6d-a5ec+3

Context object

publicclassPerson{publicstringname;publicstringLastName{get;set;}publicDateTimeBirthDate{get;set;}publicintGetTheAgeIfTodayIs(DateTimedate){varage=date.Year-BirthDate.Year;if(BirthDate.Date>date.AddYears(-age))age--;returnage;}}// ...evaluator.Context=newPerson(){name="John",LastName="Smith",BirthDate=newDateTime(1985,09,11)};

name + " " + LastNameJohn SmithGetTheAgeIfTodayIs(new DateTime(2016, 5, 14))30

Standard functions

On the fly variables and functions evaluation

ExpressionEvaluatorevaluator=newExpressionEvaluator();// always evaluated before other var and func evaluationsevaluator.PreEvaluateVariable+=Evaluator_PreEvaluateVariable;evaluator.PreEvaluateFunction+=Evaluator_PreEvaluateFunction;// evaluated if no existing var or func existsevaluator.EvaluateVariable+=Evaluator_EvaluateVariable;evaluator.EvaluateFunction+=Evaluator_EvaluateFunction;//...privatestaticvoidEvaluator_PreEvaluateVariable(objectsender,VariablePreEvaluationEventArge){if(e.Name.Equals("myvar1")){e.Value=5;}elseif(e.Name.StartsWith("P")){e.CancelEvaluation=true;}}privatestaticvoidEvaluator_PreEvaluateFunction(objectsender,FunctionPreEvaluationEventArge){if(e.Name.Equals("Test")&&e.Args.Count==1){e.Value=$"It is a test for{e.EvaluateArg(0)}";}elseif(e.Name.StartsWith("A")){e.CancelEvaluation=true;}}privatestaticvoidEvaluator_EvaluateVariable(objectsender,VariableEvaluationEventArge){if(e.Name.ToLower().Equals("myvar2")){e.Value=8;}elseif(e.Name.Equals("MultipliedBy2")&&e.ThisisintintValue){e.Value=intValue*2;}elseif(e.Name.Equals("GenericAssembly")&&e.HasGenericTypes){// e.EvaluateGenericTypes() return a Type[]e.Value=e.EvaluateGenericTypes()[0].Assembly.GetName().Name;}}privatestaticvoidEvaluator_EvaluateFunction(objectsender,FunctionEvaluationEventArge){if(e.Name.ToLower().Equals("sayhello")&&e.Args.Count==1){e.Value=$"Hello{e.EvaluateArg(0)}";}elseif(e.Name.Equals("Add")&&e.ThisisintintValue){e.Value=intValue+(int)e.EvaluateArg(0);}elseif(e.Name.Equals("GenericNamespace")&&e.HasGenericTypes){// e.EvaluateGenericTypes() return a Type[]e.Value=e.EvaluateGenericTypes()[0].Namespace;}}

myvar1 + 27Pithrow an exception (Pi not found)Test(5)It is a test for 5Abs(-3)throw an exception (Abs not found)myVar2 + 210SayHello("Bob")Hello Bob3.MultipliedBy263.Add(2)5GenericNamespace<List<string>>()System.Collections.GenericGenericAssembly<string>mscorlib

Extension methods

publicstaticclassStringExtendedMethods{publicstaticstringAddExtended(thisstringstr){returnstr+" extended";}}// ...ExpressionEvaluatorevaluator=newExpressionEvaluator(newDictionary<string,object>(){{"x","Test"}});evaluator.StaticTypesForExtensionsMethods.Add(typeof(StringExtendedMethods));

x.AddExtended()Test extended

usingSystem.Collections.Generic;usingSystem.Linq;usingSystem.Reflection;usingSystem.Runtime.CompilerServices;// ...foreach(AssemblyassemblyinAppDomain.CurrentDomain.GetAssemblies()){foreach(Typetypeinassembly.GetTypes()){if(type.IsSealed&&!type.IsGenericType&&!type.IsNested&&type.GetMethods(BindingFlags.Static|BindingFlags.Public|BindingFlags.NonPublic).ToList().Any(method=>method.IsDefined(typeof(ExtensionAttribute),false))){evaluator.StaticTypesForExtensionsMethods.Add(type);}}}

Go fluid with a simple methods prefixing convention

// Example Add on ListList("hello","bye").FluidAdd("test").Count3List("hello","bye").Select(x=>x.ToUpper()).ToList().FluentAdd("test")[0]HELLOList("hello","bye").Select(x=>x.ToUpper()).ToList().FluentAdd("test")[1]BYEList("hello","bye").Select(x=>x.ToUpper()).ToList().FluentAdd("test")[2]testList("hello","bye").Select(x=>x.ToUpper()).ToList().FluentAdd("test").FluidForEach(t=>Console.WriteLine(t)).CountHELLOBYEtest3

evaluator.OptionFluidPrefixingActive = false;

Declare and init variables in scripts

// Only supported from version 1.4.3.0intx=2;stringtext="hello";List<string>myList=newList<string>();for(inti=0;i<10;i++)...// If you have an older version. Write this instead :// Still available (for old script compatibility)x=2;text="hello";myList=newList<string>();for(i=0;i<10;i++)...// From version 1.4.0.0 you can also write// Still available (for old script compatibility)var x=2;vartext="hello";varmyList=newList<string>();for(vari=0;i<10;i++)

// This code remove all strongly typed variables of the Variable dictionnary.evaluator.Variables.ToList().FindAll(kvp=>kvp.ValueisStronglyTypedVariable).ForEach(kvp=>evaluator.Variables.Remove(kvp.Key));

Simulate function and methods declaration with lambda and multiline lambda

--------------------------------------------Add = (x, y) => x+y;Add(3, 2);---------------- Result --------------------5--------------------------------------------SayHelloTo = (name) =>{    hello = "Hye";    return $"{hello} {name}";};SayHelloTo("Joe");---------------- Result --------------------Hye Joe