feat(dotnet): handling optional and variadic parameters

packages/jsii-pacmak/lib/targets/dotnet/dotnetgenerator.ts

@@ -229,26 +229,20 @@ export class DotNetGenerator extends Generator {
         this.code.openBlock(`public${inner}${absPrefix} class ${className}${implementsExpr}`);
 
         // Compute the class parameters
-        // TODO: add the support for optional parameters
-        // Not achievable as of today and not supported by the current generator
-        // https://github.com/awslabs/jsii/issues/210
         let parametersDefinition = '';
         let parametersBase = '';
         const initializer = cls.initializer;
         if (initializer) {
             this.dotnetDocGenerator.emitDocs(initializer);
             this.dotnetRuntimeGenerator.emitDeprecatedAttributeIfNecessary(initializer);
             if (initializer.parameters) {
+                parametersDefinition = this.renderParametersString(initializer.parameters);
                 for (const p of initializer.parameters) {
-                    const pType = this.typeresolver.toDotNetType(p.type);
-                    const isOptionalPrimitive = this.isOptionalPrimitive(p) ? '?' : '';
-                    if (parametersDefinition !== '') {
-                        parametersDefinition += ', ';
+                    parametersBase += `${this.nameutils.convertParameterName(p.name)}`;
+                    // If this is not the last parameter, append ,
+                    if (initializer.parameters.indexOf(p) !== initializer.parameters.length - 1) {
                         parametersBase += ', ';
                     }
-                    parametersDefinition += `${pType}${isOptionalPrimitive} ${this.nameutils.convertParameterName(p.name)}`;
-                    parametersBase += `${this.nameutils.convertParameterName(p.name)}`;
-
                 }
             }
 
@@ -443,18 +437,36 @@ export class DotNetGenerator extends Generator {
         }
     }
 
-    // TODO: I uncovered an issue with optional parameters and ordering them
-    // They are currently not supported by the generator.
-    // In C#, optional parameters need to be declared after required parameters
-    // We could make changes to the parameters ordering in the jsii model to support them
-    // But then an optional parameter becoming non optional would create a mess
-    // https://github.com/awslabs/jsii/issues/210
+    /**
+     * Renders method parameters string
+     */
     private renderMethodParameters(method: spec.Method): string {
+        return this.renderParametersString(method.parameters);
+    }
+
+    /**
+     * Renders parameters string for methods or constructors
+     */
+    private renderParametersString(parameters: spec.Parameter[] | undefined): string {
         const params = [];
-        if (method.parameters) {
-            for (const p of method.parameters) {
-                const isOptionalPrimitive = this.isOptionalPrimitive(p) ? '?' : '';
-                const st = `${this.typeresolver.toDotNetType(p.type)}${isOptionalPrimitive} ${this.nameutils.convertParameterName(p.name)}`;
+        if (parameters) {
+            for (const p of parameters) {
+                let optionalPrimitive = '';
+                let optionalKeyword = '';
+                let type = this.typeresolver.toDotNetType(p.type);
+                if (p.optional) {
+                    if (this.isOptionalPrimitive(p)) {
+                        optionalPrimitive = '?';
+                        optionalKeyword = ' = null';
+                    } else {
+                        optionalKeyword = ' = null';
+                    }
+                }
+                if (p.variadic) {
+                    type = `params ${type}[]`;
+                }
+                const st =
+                    `${type}${optionalPrimitive} ${this.nameutils.convertParameterName(p.name)}${optionalKeyword}`;
                 params.push(st);
             }
         }
@@ -637,7 +649,6 @@ export class DotNetGenerator extends Generator {
         let isVirtualKeyWord = '';
         // If the prop parent is a class
         if (cls.kind === spec.TypeKind.Class) {
-
             const implementedInBase = this.isMemberDefinedOnAncestor(cls as spec.ClassType, prop);
             if (implementedInBase || datatype || proxy) {
                 // Override if the property is in a datatype or proxy class or declared in a parent class

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/Calculator.cs

@@ -14,7 +14,7 @@ public class Calculator : Amazon.JSII.Tests.CalculatorNamespace.composition.Comp
         /// <remarks>
         /// stability: Experimental
         /// </remarks>
-        public Calculator(Amazon.JSII.Tests.CalculatorNamespace.ICalculatorProps props): base(new DeputyProps(new object[]{props}))
+        public Calculator(Amazon.JSII.Tests.CalculatorNamespace.ICalculatorProps props = null): base(new DeputyProps(new object[]{props}))
         {
         }
 

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/DataRenderer.cs

@@ -28,7 +28,7 @@ protected DataRenderer(DeputyProps props): base(props)
         /// stability: Experimental
         /// </remarks>
         [JsiiMethod(name: "render", returnsJson: "{\"type\":{\"primitive\":\"string\"}}", parametersJson: "[{\"name\":\"data\",\"optional\":true,\"type\":{\"fqn\":\"@scope/jsii-calc-lib.MyFirstStruct\"}}]")]
-        public virtual string Render(Amazon.JSII.Tests.CalculatorNamespace.LibNamespace.IMyFirstStruct data)
+        public virtual string Render(Amazon.JSII.Tests.CalculatorNamespace.LibNamespace.IMyFirstStruct data = null)
         {
             return InvokeInstanceMethod<string>(new object[]{data});
         }

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/DefaultedConstructorArgument.cs

@@ -11,7 +11,7 @@ public class DefaultedConstructorArgument : DeputyBase
         /// <remarks>
         /// stability: Experimental
         /// </remarks>
-        public DefaultedConstructorArgument(double? arg1, string arg2, System.DateTime? arg3): base(new DeputyProps(new object[]{arg1, arg2, arg3}))
+        public DefaultedConstructorArgument(double? arg1 = null, string arg2 = null, System.DateTime? arg3 = null): base(new DeputyProps(new object[]{arg1, arg2, arg3}))
         {
         }
 

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/DeprecatedClass.cs

@@ -13,7 +13,7 @@ public class DeprecatedClass : DeputyBase
         /// stability: Deprecated
         /// </remarks>
         [System.Obsolete("this constructor is \"just\" okay")]
-        public DeprecatedClass(string readonlyString, double? mutableNumber): base(new DeputyProps(new object[]{readonlyString, mutableNumber}))
+        public DeprecatedClass(string readonlyString, double? mutableNumber = null): base(new DeputyProps(new object[]{readonlyString, mutableNumber}))
         {
         }
 

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/DoNotRecognizeAnyAsOptional.cs

@@ -25,7 +25,7 @@ protected DoNotRecognizeAnyAsOptional(DeputyProps props): base(props)
         /// stability: Experimental
         /// </remarks>
         [JsiiMethod(name: "method", parametersJson: "[{\"name\":\"_requiredAny\",\"type\":{\"primitive\":\"any\"}},{\"name\":\"_optionalAny\",\"optional\":true,\"type\":{\"primitive\":\"any\"}},{\"name\":\"_optionalString\",\"optional\":true,\"type\":{\"primitive\":\"string\"}}]")]
-        public virtual void Method(object requiredAny, object optionalAny, string optionalString)
+        public virtual void Method(object requiredAny, object optionalAny = null, string optionalString = null)
         {
             InvokeInstanceVoidMethod(new object[]{requiredAny, optionalAny, optionalString});
         }

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/DocumentedClass.cs

@@ -36,7 +36,7 @@ protected DocumentedClass(DeputyProps props): base(props)
         /// stability: Stable
         /// </remarks>
         [JsiiMethod(name: "greet", returnsJson: "{\"type\":{\"primitive\":\"number\"}}", parametersJson: "[{\"docs\":{\"summary\":\"The person to be greeted.\"},\"name\":\"greetee\",\"optional\":true,\"type\":{\"fqn\":\"jsii-calc.Greetee\"}}]")]
-        public virtual double Greet(Amazon.JSII.Tests.CalculatorNamespace.IGreetee greetee)
+        public virtual double Greet(Amazon.JSII.Tests.CalculatorNamespace.IGreetee greetee = null)
         {
             return InvokeInstanceMethod<double>(new object[]{greetee});
         }

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/DontComplainAboutVariadicAfterOptional.cs

@@ -24,7 +24,7 @@ protected DontComplainAboutVariadicAfterOptional(DeputyProps props): base(props)
         /// stability: Experimental
         /// </remarks>
         [JsiiMethod(name: "optionalAndVariadic", returnsJson: "{\"type\":{\"primitive\":\"string\"}}", parametersJson: "[{\"name\":\"optional\",\"optional\":true,\"type\":{\"primitive\":\"string\"}},{\"name\":\"things\",\"type\":{\"primitive\":\"string\"},\"variadic\":true}]")]
-        public virtual string OptionalAndVariadic(string optional, string things)
+        public virtual string OptionalAndVariadic(string optional = null, params string[] things)
         {
             return InvokeInstanceMethod<string>(new object[]{optional, things});
         }

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/ExperimentalClass.cs

@@ -11,7 +11,7 @@ public class ExperimentalClass : DeputyBase
         /// <remarks>
         /// stability: Experimental
         /// </remarks>
-        public ExperimentalClass(string readonlyString, double? mutableNumber): base(new DeputyProps(new object[]{readonlyString, mutableNumber}))
+        public ExperimentalClass(string readonlyString, double? mutableNumber = null): base(new DeputyProps(new object[]{readonlyString, mutableNumber}))
         {
         }
 

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/IIInterfaceWithOptionalMethodArguments.cs

@@ -13,6 +13,6 @@ public interface IIInterfaceWithOptionalMethodArguments
         /// stability: Experimental
         /// </remarks>
         [JsiiMethod(name: "hello", parametersJson: "[{\"name\":\"arg1\",\"type\":{\"primitive\":\"string\"}},{\"name\":\"arg2\",\"optional\":true,\"type\":{\"primitive\":\"number\"}}]")]
-        void Hello(string arg1, double? arg2);
+        void Hello(string arg1, double? arg2 = null);
     }
 }

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/IInterfaceWithOptionalMethodArgumentsProxy.cs

@@ -17,7 +17,7 @@ private IInterfaceWithOptionalMethodArgumentsProxy(ByRefValue reference): base(r
         /// stability: Experimental
         /// </remarks>
         [JsiiMethod(name: "hello", parametersJson: "[{\"name\":\"arg1\",\"type\":{\"primitive\":\"string\"}},{\"name\":\"arg2\",\"optional\":true,\"type\":{\"primitive\":\"number\"}}]")]
-        public void Hello(string arg1, double? arg2)
+        public void Hello(string arg1, double? arg2 = null)
         {
             InvokeInstanceVoidMethod(new object[]{arg1, arg2});
         }

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/NullShouldBeTreatedAsUndefined.cs

@@ -12,7 +12,7 @@ public class NullShouldBeTreatedAsUndefined : DeputyBase
         /// <remarks>
         /// stability: Experimental
         /// </remarks>
-        public NullShouldBeTreatedAsUndefined(string param1, object optional): base(new DeputyProps(new object[]{param1, optional}))
+        public NullShouldBeTreatedAsUndefined(string param1, object optional = null): base(new DeputyProps(new object[]{param1, optional}))
         {
         }
 
@@ -28,7 +28,7 @@ protected NullShouldBeTreatedAsUndefined(DeputyProps props): base(props)
         /// stability: Experimental
         /// </remarks>
         [JsiiMethod(name: "giveMeUndefined", parametersJson: "[{\"name\":\"value\",\"optional\":true,\"type\":{\"primitive\":\"any\"}}]")]
-        public virtual void GiveMeUndefined(object @value)
+        public virtual void GiveMeUndefined(object @value = null)
         {
             InvokeInstanceVoidMethod(new object[]{@value});
         }

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/OptionalConstructorArgument.cs

@@ -11,7 +11,7 @@ public class OptionalConstructorArgument : DeputyBase
         /// <remarks>
         /// stability: Experimental
         /// </remarks>
-        public OptionalConstructorArgument(double arg1, string arg2, System.DateTime? arg3): base(new DeputyProps(new object[]{arg1, arg2, arg3}))
+        public OptionalConstructorArgument(double arg1, string arg2, System.DateTime? arg3 = null): base(new DeputyProps(new object[]{arg1, arg2, arg3}))
         {
         }
 

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/OptionalStructConsumer.cs

@@ -11,7 +11,7 @@ public class OptionalStructConsumer : DeputyBase
         /// <remarks>
         /// stability: Experimental
         /// </remarks>
-        public OptionalStructConsumer(Amazon.JSII.Tests.CalculatorNamespace.IOptionalStruct optionalStruct): base(new DeputyProps(new object[]{optionalStruct}))
+        public OptionalStructConsumer(Amazon.JSII.Tests.CalculatorNamespace.IOptionalStruct optionalStruct = null): base(new DeputyProps(new object[]{optionalStruct}))
         {
         }
 

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/RuntimeTypeChecking.cs

@@ -24,7 +24,7 @@ protected RuntimeTypeChecking(DeputyProps props): base(props)
         /// stability: Experimental
         /// </remarks>
         [JsiiMethod(name: "methodWithDefaultedArguments", parametersJson: "[{\"name\":\"arg1\",\"optional\":true,\"type\":{\"primitive\":\"number\"}},{\"name\":\"arg2\",\"optional\":true,\"type\":{\"primitive\":\"string\"}},{\"name\":\"arg3\",\"optional\":true,\"type\":{\"primitive\":\"date\"}}]")]
-        public virtual void MethodWithDefaultedArguments(double? arg1, string arg2, System.DateTime? arg3)
+        public virtual void MethodWithDefaultedArguments(double? arg1 = null, string arg2 = null, System.DateTime? arg3 = null)
         {
             InvokeInstanceVoidMethod(new object[]{arg1, arg2, arg3});
         }
@@ -33,7 +33,7 @@ public virtual void MethodWithDefaultedArguments(double? arg1, string arg2, Syst
         /// stability: Experimental
         /// </remarks>
         [JsiiMethod(name: "methodWithOptionalAnyArgument", parametersJson: "[{\"name\":\"arg\",\"optional\":true,\"type\":{\"primitive\":\"any\"}}]")]
-        public virtual void MethodWithOptionalAnyArgument(object arg)
+        public virtual void MethodWithOptionalAnyArgument(object arg = null)
         {
             InvokeInstanceVoidMethod(new object[]{arg});
         }
@@ -43,7 +43,7 @@ public virtual void MethodWithOptionalAnyArgument(object arg)
         /// stability: Experimental
         /// </remarks>
         [JsiiMethod(name: "methodWithOptionalArguments", parametersJson: "[{\"name\":\"arg1\",\"type\":{\"primitive\":\"number\"}},{\"name\":\"arg2\",\"type\":{\"primitive\":\"string\"}},{\"name\":\"arg3\",\"optional\":true,\"type\":{\"primitive\":\"date\"}}]")]
-        public virtual void MethodWithOptionalArguments(double arg1, string arg2, System.DateTime? arg3)
+        public virtual void MethodWithOptionalArguments(double arg1, string arg2, System.DateTime? arg3 = null)
         {
             InvokeInstanceVoidMethod(new object[]{arg1, arg2, arg3});
         }

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/StableClass.cs

@@ -11,7 +11,7 @@ public class StableClass : DeputyBase
         /// <remarks>
         /// stability: Stable
         /// </remarks>
-        public StableClass(string readonlyString, double? mutableNumber): base(new DeputyProps(new object[]{readonlyString, mutableNumber}))
+        public StableClass(string readonlyString, double? mutableNumber = null): base(new DeputyProps(new object[]{readonlyString, mutableNumber}))
         {
         }
 

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/StructPassing.cs

@@ -25,7 +25,7 @@ protected StructPassing(DeputyProps props): base(props)
         /// stability: External
         /// </remarks>
         [JsiiMethod(name: "howManyVarArgsDidIPass", returnsJson: "{\"type\":{\"primitive\":\"number\"}}", parametersJson: "[{\"name\":\"_positional\",\"type\":{\"primitive\":\"number\"}},{\"name\":\"inputs\",\"type\":{\"fqn\":\"jsii-calc.TopLevelStruct\"},\"variadic\":true}]")]
-        public static double HowManyVarArgsDidIPass(double positional, Amazon.JSII.Tests.CalculatorNamespace.ITopLevelStruct inputs)
+        public static double HowManyVarArgsDidIPass(double positional, params Amazon.JSII.Tests.CalculatorNamespace.ITopLevelStruct[] inputs)
         {
             return InvokeStaticMethod<double>(typeof(Amazon.JSII.Tests.CalculatorNamespace.StructPassing), new object[]{positional, inputs});
         }

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/VariadicMethod.cs

@@ -12,7 +12,7 @@ public class VariadicMethod : DeputyBase
         /// <remarks>
         /// stability: Experimental
         /// </remarks>
-        public VariadicMethod(double prefix): base(new DeputyProps(new object[]{prefix}))
+        public VariadicMethod(params double[] prefix): base(new DeputyProps(new object[]{prefix}))
         {
         }
 
@@ -30,7 +30,7 @@ protected VariadicMethod(DeputyProps props): base(props)
         /// stability: Experimental
         /// </remarks>
         [JsiiMethod(name: "asArray", returnsJson: "{\"type\":{\"collection\":{\"elementtype\":{\"primitive\":\"number\"},\"kind\":\"array\"}}}", parametersJson: "[{\"docs\":{\"summary\":\"the first element of the array to be returned (after the `prefix` provided at construction time).\"},\"name\":\"first\",\"type\":{\"primitive\":\"number\"}},{\"docs\":{\"summary\":\"other elements to be included in the array.\"},\"name\":\"others\",\"type\":{\"primitive\":\"number\"},\"variadic\":true}]")]
-        public virtual double[] AsArray(double first, double others)
+        public virtual double[] AsArray(double first, params double[] others)
         {
             return InvokeInstanceMethod<double[]>(new object[]{first, others});
         }

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/WithPrivatePropertyInConstructor.cs

@@ -12,7 +12,7 @@ public class WithPrivatePropertyInConstructor : DeputyBase
         /// <remarks>
         /// stability: Experimental
         /// </remarks>
-        public WithPrivatePropertyInConstructor(string privateField): base(new DeputyProps(new object[]{privateField}))
+        public WithPrivatePropertyInConstructor(string privateField = null): base(new DeputyProps(new object[]{privateField}))
         {
         }