Update DSL implementation and integration (#4073)

Elsa.sln

@@ -202,6 +202,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Elsa.Environments", "src\mo
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Elsa.EntityFrameworkCore.MySql", "src\modules\Elsa.EntityFrameworkCore.MySql\Elsa.EntityFrameworkCore.MySql.csproj", "{8DC74562-1F06-4AFA-8308-8A779E8812A3}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Elsa.Samples.AspNet.DslWorkflowProvider", "src\samples\aspnet\Elsa.Samples.AspNet.DslWorkflowProvider\Elsa.Samples.AspNet.DslWorkflowProvider.csproj", "{4BC5D3D2-9425-41D7-9804-D145B92520EE}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -516,6 +518,10 @@ Global
 		{8DC74562-1F06-4AFA-8308-8A779E8812A3}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{8DC74562-1F06-4AFA-8308-8A779E8812A3}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{8DC74562-1F06-4AFA-8308-8A779E8812A3}.Release|Any CPU.Build.0 = Release|Any CPU
+		{4BC5D3D2-9425-41D7-9804-D145B92520EE}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{4BC5D3D2-9425-41D7-9804-D145B92520EE}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{4BC5D3D2-9425-41D7-9804-D145B92520EE}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{4BC5D3D2-9425-41D7-9804-D145B92520EE}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(NestedProjects) = preSolution
 		{155227F0-A33B-40AA-A4B4-06F813EB921B} = {61017E64-6D00-49CB-9E81-5002DC8F7D5F}
@@ -606,5 +612,6 @@ Global
 		{165ACC9D-B67C-4B49-A818-ECFD247C899C} = {56C2FFB8-EA54-45B5-A095-4A78142EB4B5}
 		{B5CDF747-8066-40D5-9BAE-CBE397BC9B51} = {5BA4A8FA-F7F4-45B3-AEC8-8886D35AAC79}
 		{8DC74562-1F06-4AFA-8308-8A779E8812A3} = {5BA4A8FA-F7F4-45B3-AEC8-8886D35AAC79}
+		{4BC5D3D2-9425-41D7-9804-D145B92520EE} = {56C2FFB8-EA54-45B5-A095-4A78142EB4B5}
 	EndGlobalSection
 EndGlobal

src/common/Elsa.Features/Implementations/Module.cs

@@ -14,7 +14,7 @@ namespace Elsa.Features.Implementations;
 /// <inheritdoc />
 public class Module : IModule
 {
-    private record HostedServiceDescriptor(int Order, Type HostedServiceType);
+    private record HostedServiceDescriptor(int Order, Type Type);
 
     private IDictionary<Type, IFeature> _features = new Dictionary<Type, IFeature>();
     private readonly ISet<IFeature> _configuredFeatures = new HashSet<IFeature>();
@@ -84,12 +84,12 @@ public void Apply()
         }
 
         foreach (var hostedServiceDescriptor in _hostedServiceDescriptors.OrderBy(x => x.Order))
-            Services.TryAddEnumerable(ServiceDescriptor.Singleton(typeof(IHostedService), hostedServiceDescriptor.HostedServiceType));
+            Services.TryAddEnumerable(ServiceDescriptor.Singleton(typeof(IHostedService), hostedServiceDescriptor.Type));
 
         // Make sure to use the complete list of features when applying them.
         foreach (var feature in _features.Values)
             feature.Apply();
-        
+
         // Add a registry of enabled features to the service collection for client applications to reflect on what features are installed.
         var registry = new InstalledFeatureRegistry();
         foreach (var feature in _features.Values)

src/common/Elsa.Features/Services/IModule.cs

@@ -17,22 +17,22 @@ public interface IModule
     /// A dictionary into which features can stash away values for later use. 
     /// </summary>
     IDictionary<object, object> Properties { get; }
-    
+
     /// <summary>
     /// Creates and configures a feature of the specified type.
     /// </summary>
     T Configure<T>(Action<T>? configure = default) where T : class, IFeature;
-    
+
     /// <summary>
     /// Creates and configures a feature of the specified type.
     /// </summary>
     T Configure<T>(Func<IModule, T> factory, Action<T>? configure = default) where T : class, IFeature;
-    
+
     /// <summary>
     /// Configures a <see cref="IHostedService"/> using an optional priority to control in which order it will be registered with the service container.
     /// </summary>
     IModule ConfigureHostedService<T>(int priority = 0) where T : class, IHostedService;
-    
+
     /// <summary>
     /// Will apply all configured features, causing the <see cref="Services"/> collection to be populated. 
     /// </summary>

src/common/Elsa.Testing.Shared/TestApplicationBuilder.cs

@@ -37,6 +37,7 @@ public TestApplicationBuilder(ITestOutputHelper testOutputHelper)
             .UseScheduling()
             .UseJavaScript()
             .UseLiquid()
+            .UseDsl()
             .UseWorkflows(workflows => workflows
                 .WithStandardOutStreamProvider(_ => new StandardOutStreamProvider(new XunitConsoleTextWriter(_testOutputHelper)))
             );

src/modules/Elsa.Dsl/Contracts/IFunctionActivityRegistry.cs

@@ -1,9 +1,33 @@
+using Elsa.Dsl.Models;
 using Elsa.Workflows.Core.Contracts;
 
 namespace Elsa.Dsl.Contracts;
 
+/// <summary>
+/// Provides a registry for mapping functions to activities that can be invoked from a DSL script.
+/// </summary>
 public interface IFunctionActivityRegistry
 {
-    void RegisterFunction(string functionName, string activityTypeName, IEnumerable<string>? propertyNames = default);
+    /// <summary>
+    /// Registers a function that is mapped to an activity that can be invoked from a DSL script.
+    /// </summary>
+    /// <param name="functionName">The name of the function.</param>
+    /// <param name="activityTypeName">The name of the activity type.</param>
+    /// <param name="propertyNames">The names of the properties that are mapped to the function arguments.</param>
+    /// <param name="configure">An optional action that can be used to configure the activity.</param>
+    void RegisterFunction(string functionName, string activityTypeName, IEnumerable<string>? propertyNames = default, Action<IActivity>? configure = default);
+
+    /// <summary>
+    /// Registers a function that is mapped to an activity that can be invoked from a DSL script.
+    /// </summary>
+    /// <param name="descriptor">The descriptor that describes the function.</param>
+    void RegisterFunction(FunctionActivityDescriptor descriptor);
+
+    /// <summary>
+    /// Resolves a function to an activity that can be invoked from a DSL script.
+    /// </summary>
+    /// <param name="functionName">The name of the function.</param>
+    /// <param name="arguments">The arguments that are passed to the function.</param>
+    /// <returns>An activity that can be invoked from a DSL script.</returns>
     IActivity ResolveFunction(string functionName, IEnumerable<object?>? arguments = default);
 }

src/modules/Elsa.Dsl/Interpreters/WorkflowDefinitionBuilderInterpreter/VisitBrackets.cs

@@ -5,20 +5,21 @@ namespace Elsa.Dsl.Interpreters;
 
 public partial class WorkflowDefinitionBuilderInterpreter
 {
+    /// <inheritdoc />
     public override IWorkflowBuilder VisitBracketsExpr(ElsaParser.BracketsExprContext context)
     {
         var propertyType = _expressionType.Get(context.Parent);
-        var targetElementType = propertyType.GetGenericArguments().First();
+        var targetElementType = propertyType?.GetGenericArguments().First() ?? typeof(object);
         var contents = context.exprList().expr();
 
         var items = contents.Select(x =>
         {
             Visit(x);
-            var objectContext = x.GetChild<ElsaParser.ObjectContext>(0);
-            return _expressionValue.Get(objectContext);
+            var stringContext = x.GetChild<ElsaParser.StringValueExprContext>(0) ?? x;
+            return _expressionValue.Get(stringContext);
         }).ToList();
 
-        var stronglyTypedListType = typeof(ICollection<>).MakeGenericType(targetElementType);
+        var stronglyTypedListType = targetElementType;
         var stronglyTypedList = items.ConvertTo(stronglyTypedListType);
 
         _expressionValue.Put(context, stronglyTypedList);

src/modules/Elsa.Dsl/Interpreters/WorkflowDefinitionBuilderInterpreter/VisitObject.cs

@@ -1,9 +1,12 @@
-using Elsa.Workflows.Core.Contracts;
+using System.Text.Json;
+using Elsa.Workflows.Core.Contracts;
+using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Dsl.Interpreters;
 
 public partial class WorkflowDefinitionBuilderInterpreter
 {
+    /// <inheritdoc />
     public override IWorkflowBuilder VisitObjectExpr(ElsaParser.ObjectExprContext context)
     {
         VisitChildren(context);
@@ -13,6 +16,7 @@ public override IWorkflowBuilder VisitObjectExpr(ElsaParser.ObjectExprContext co
         return DefaultResult;
     }
 
+    /// <inheritdoc />
     public override IWorkflowBuilder VisitObjectStat(ElsaParser.ObjectStatContext context)
     {
         VisitChildren(context);
@@ -22,9 +26,34 @@ public override IWorkflowBuilder VisitObjectStat(ElsaParser.ObjectStatContext co
         return DefaultResult;
     }
 
+    /// <inheritdoc />
     public override IWorkflowBuilder VisitObject(ElsaParser.ObjectContext context)
+    {
+        var @object = GetObject(context);
+
+        _object.Put(context, @object);
+        _expressionValue.Put(context, @object);
+        VisitChildren(context);
+
+        return DefaultResult;
+    }
+
+    private object GetObject(ElsaParser.ObjectContext context)
     {
         var objectTypeName = context.ID().GetText();
+
+        // First, check if the symbol matches an activity type.
+        var activityType = _activityRegistry.Find(x => x.Name == objectTypeName);
+
+        if (activityType != null)
+        {
+            // TODO: Refactor this to remove the dependency on JsonElement and JsonSerializerOptions.
+            // This limits the ability to use this class in other contexts, such as constructing activities from the DSL.
+            var jsonElement = JsonSerializer.Deserialize<JsonElement>("{}");
+            var ctorArgs = new ActivityConstructorContext(jsonElement, new JsonSerializerOptions());
+            return activityType.Constructor(ctorArgs);
+        }
+
         var objectTypeDescriptor = _typeSystem.ResolveTypeName(objectTypeName);
 
         if (objectTypeDescriptor == null)
@@ -35,7 +64,7 @@ public override IWorkflowBuilder VisitObject(ElsaParser.ObjectContext context)
                 _expressionValue.Put(context, definedVariable.Value);
                 return DefaultResult;
             }
-                
+
             // Or a workflow variable?
             var workflowVariableQuery =
                 from container in _containerStack
@@ -50,17 +79,13 @@ from variable in container.Variables
                 _expressionValue.Put(context, workflowVariable);
                 return DefaultResult;
             }
-                
+
             throw new Exception($"Unknown type: {objectTypeName}");
         }
 
         var objectType = objectTypeDescriptor.Type;
         var @object = Activator.CreateInstance(objectType)!;
 
-        _object.Put(context, @object);
-        _expressionValue.Put(context, @object);
-        VisitChildren(context);
-
-        return DefaultResult;
+        return @object;
     }
 }

src/modules/Elsa.Dsl/Interpreters/WorkflowDefinitionBuilderInterpreter/VisitProperty.cs

@@ -1,12 +1,14 @@
 using System.Reflection;
 using Elsa.Expressions.Helpers;
+using Elsa.Expressions.Models;
 using Elsa.Workflows.Core.Contracts;
 using Elsa.Workflows.Core.Models;
 
 namespace Elsa.Dsl.Interpreters;
 
 public partial class WorkflowDefinitionBuilderInterpreter
 {
+    /// <inheritdoc />
     public override IWorkflowBuilder VisitProperty(ElsaParser.PropertyContext context)
     {
         var @object = _object.Get(context.Parent.Parent.Parent);
@@ -21,7 +23,9 @@ public override IWorkflowBuilder VisitProperty(ElsaParser.PropertyContext contex
         VisitChildren(context);
 
         var propertyValue = _expressionValue.Get(context.expr());
-        SetPropertyValue(@object, propertyInfo, propertyValue);
+        var propertyType = propertyInfo.PropertyType;
+        var parsedPropertyValue = typeof(Input).IsAssignableFrom(propertyType) ? propertyValue : propertyValue.ConvertTo(propertyType);
+        SetPropertyValue(@object, propertyInfo, parsedPropertyValue);
 
         return DefaultResult;
     }
@@ -37,19 +41,25 @@ private void SetPropertyValue(object target, PropertyInfo propertyInfo, object?
     private Input CreateInputValue(PropertyInfo propertyInfo, object? propertyValue)
     {
         var underlyingType = propertyInfo.PropertyType.GetGenericArguments().First();
-        var propertyValueType = propertyValue?.GetType();
+        var parsedPropertyValue = propertyValue.ConvertTo(underlyingType);
+        var propertyValueType = parsedPropertyValue?.GetType();
         var inputType = typeof(Input<>).MakeGenericType(underlyingType);
 
         if (propertyValueType != null)
         {
-            var hasCtorWithSpecifiedType = inputType.GetConstructors().Any(x => x.GetParameters().Any(y => y.ParameterType.IsAssignableFrom(propertyValueType)));
+            // Create a literal value.
+            var literalType = typeof(Literal<>).MakeGenericType(underlyingType);
+            var hasCtorWithSpecifiedType = inputType.GetConstructors().Any(x => x.GetParameters().Any(y => y.ParameterType.IsAssignableFrom(literalType)));
 
             if (hasCtorWithSpecifiedType)
-                return (Input)Activator.CreateInstance(inputType, propertyValue)!;
+            {
+                var literalValue = Activator.CreateInstance(literalType, parsedPropertyValue)!;
+                return (Input)Activator.CreateInstance(inputType, literalValue)!;
+            }
         }
 
-        return propertyValue is ExternalExpressionReference externalExpressionReference 
-            ? (Input)Activator.CreateInstance(inputType, externalExpressionReference.Expression, externalExpressionReference.BlockReference)! 
-            : (Input)Activator.CreateInstance(inputType, propertyValue.ConvertTo(underlyingType))!;
+        return parsedPropertyValue is ExternalExpressionReference externalExpressionReference
+            ? (Input)Activator.CreateInstance(inputType, externalExpressionReference.Expression, externalExpressionReference.BlockReference)!
+            : (Input)Activator.CreateInstance(inputType, parsedPropertyValue)!;
     }
 }

src/modules/Elsa.Dsl/Interpreters/WorkflowDefinitionBuilderInterpreter/WorkflowDefinitionBuilderInterpreter.cs

@@ -1,7 +1,6 @@
 using Antlr4.Runtime.Tree;
 using Elsa.Dsl.Contracts;
 using Elsa.Dsl.Models;
-using Elsa.Expressions.Contracts;
 using Elsa.Workflows.Core.Activities;
 using Elsa.Workflows.Core.Contracts;
 
@@ -10,8 +9,8 @@ namespace Elsa.Dsl.Interpreters;
 public partial class WorkflowDefinitionBuilderInterpreter : ElsaParserBaseVisitor<IWorkflowBuilder>
 {
     private readonly ITypeSystem _typeSystem;
+    private readonly IActivityRegistry _activityRegistry;
     private readonly IFunctionActivityRegistry _functionActivityRegistry;
-    private readonly IExpressionHandlerRegistry _expressionHandlerRegistry;
     private readonly IWorkflowBuilder _workflowBuilder;
     private readonly ParseTreeProperty<object> _object = new();
     private readonly ParseTreeProperty<object?> _expressionValue = new();
@@ -22,22 +21,17 @@ public partial class WorkflowDefinitionBuilderInterpreter : ElsaParserBaseVisito
 
     /// <inheritdoc />
     public WorkflowDefinitionBuilderInterpreter(
-        ITypeSystem typeSystem, 
-        IFunctionActivityRegistry functionActivityRegistry, 
-        IExpressionHandlerRegistry expressionHandlerRegistry,
-        IWorkflowBuilderFactory workflowBuilderFactory,
-        WorkflowDefinitionInterpreterSettings settings)
+        ITypeSystem typeSystem,
+        IActivityRegistry activityRegistry,
+        IFunctionActivityRegistry functionActivityRegistry,
+        IWorkflowBuilderFactory workflowBuilderFactory)
     {
         _typeSystem = typeSystem;
+        _activityRegistry = activityRegistry;
         _functionActivityRegistry = functionActivityRegistry;
-        _expressionHandlerRegistry = expressionHandlerRegistry;
         _workflowBuilder = workflowBuilderFactory.CreateBuilder();
     }
 
+    /// <inheritdoc />
     protected override IWorkflowBuilder DefaultResult => _workflowBuilder;
-
-    private void VisitMany(IEnumerable<IParseTree> contexts)
-    {
-        foreach (var parseTree in contexts) Visit(parseTree);
-    }
 }

src/modules/Elsa.Dsl/Models/FunctionActivityDescriptor.cs

@@ -0,0 +1,12 @@
+using Elsa.Workflows.Core.Contracts;
+
+namespace Elsa.Dsl.Models;
+
+/// <summary>
+/// Describes a function that is mapped to an activity that can be invoked from a DSL script.
+/// </summary>
+/// <param name="FunctionName">The name of the function.</param>
+/// <param name="ActivityTypeName">The name of the activity type.</param>
+/// <param name="PropertyNames">The names of the properties that are mapped to the function arguments.</param>
+/// <param name="Configure">An optional action that can be used to configure the activity.</param>
+public record FunctionActivityDescriptor(string FunctionName, string ActivityTypeName, IEnumerable<string>? PropertyNames = default, Action<IActivity>? Configure = default);