Merge pull request #9 from koculu/8-feature-create-an-interface-to-ex…

…tract-meta-information-from-topazfunction

Add ITopazFunction interface to expose function functionality and meta information.

src/Tenray.Topaz.Test/FunctionTests.cs

@@ -247,4 +247,40 @@ function f2(y) {
         Assert.AreEqual(7, model.p);
         Assert.AreEqual(14, model.q);
     }
+
+    [Test]
+    public void FunctionInformation()
+    {
+        var engine = new TopazEngine();
+        dynamic model = new JsObject();
+        engine.SetValue("model", model);
+        engine.ExecuteScript(@"
+function f1(a, b, c)
+{
+}
+function f2(a, b=34, c)
+{
+}
+model.f1 = f1
+model.f2 = f2
+");
+        var f1 = model.f1 as ITopazFunction;
+        var f2 = model.f2 as ITopazFunction;
+
+        Assert.AreEqual("f1", f1.Name);
+        Assert.AreEqual(3, f1.Length);
+        Assert.AreEqual("a", f1[0]);
+        Assert.AreEqual("b", f1[1]);
+        Assert.AreEqual("c", f1[2]);
+
+        Assert.AreEqual("f2", f2.Name);
+        Assert.AreEqual(3, f2.Length);
+        Assert.AreEqual("a", f2[0]);
+        Assert.AreEqual("b", f2[1]);
+        Assert.AreEqual("c", f2[2]);
+        f1.Invoke(new(), 1, 2, 3);
+        f2.Invoke(new(), 1, 2, 5.7);
+        f1.InvokeAsync(new(), 1, true, 3, 5);
+        f2.InvokeAsync(new(), "test", 2, 3);
+    }
 }

src/Tenray.Topaz/Directory.Build.props

@@ -5,8 +5,8 @@
     <Authors>Ahmed Yasin Koculu</Authors>
     <PackageId>Topaz</PackageId>
     <Title>Topaz</Title>
-    <ProductVersion>1.2.7.0</ProductVersion>
-    <Version>1.2.7.0</Version>
+    <ProductVersion>1.2.8.0</ProductVersion>
+    <Version>1.2.8.0</Version>
     <Authors>Ahmed Yasin Koculu</Authors>
     <AssemblyTitle>Topaz</AssemblyTitle>
     <Description>Multithreaded Javascript Engine for .NET</Description>

src/Tenray.Topaz/ITopazEngine.cs

@@ -24,7 +24,7 @@ public interface ITopazEngine
     /// Engine Options.
     /// </summary>
     TopazEngineOptions Options { get; set; }
-    
+
     /// <summary>
     /// Global Scope.
     /// </summary>
@@ -132,14 +132,14 @@ public interface ITopazEngine
     /// <param name="name"></param>
     /// <param name="typeProxy"></param>
     void AddType<T>(string name = null, ITypeProxy typeProxy = null);
-    
+
     /// <summary>
     /// Adds a type to be used in Javascript.
     /// </summary>
     /// <param name="type"></param>
     /// <param name="name"></param>
     /// <param name="typeProxy"></param>
-    void AddType(Type type,string name = null, ITypeProxy typeProxy = null);
+    void AddType(Type type, string name = null, ITypeProxy typeProxy = null);
 
     /// <summary>
     /// Adds extension methods defined in type.

src/Tenray.Topaz/ITopazFunction.cs

@@ -0,0 +1,41 @@
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Tenray.Topaz;
+
+public interface ITopazFunction
+{
+    /// <summary>
+    /// Gets name of the function.
+    /// </summary>
+    string Name { get; }
+
+    /// <summary>
+    /// Gets the number of arguments of the function.
+    /// </summary>
+    int Length { get; }
+
+    /// <summary>
+    /// Gets the nth argument name of the function.
+    /// </summary>
+    /// <param name="index">The index of the argument.</param>
+    /// <returns>Name of the argument.</returns>
+    string this[int index] { get; }
+
+    /// <summary>
+    /// Invokes the function using arguments.
+    /// </summary>    
+    /// <param name="token">CancellationToken.</param>
+    /// <param name="args">Arguments.</param>
+    /// <returns>The object returned from function implementation.</returns>
+    object Invoke(CancellationToken token, params object[] args);
+
+    /// <summary>
+    /// Invokes the function asynchronously using arguments.
+    /// </summary>
+    /// <param name="args">Arguments.</param>
+    /// <param name="token">CancellationToken.</param>
+    /// <returns>The object returned from function implementation.</returns>
+    ValueTask<object> InvokeAsync(CancellationToken token, params object[] args);
+}

src/Tenray.Topaz/Wrappers/TopazFunction.cs

@@ -15,11 +15,15 @@
 
 namespace Tenray.Topaz;
 
-internal sealed class TopazFunction : IConvertible
+internal sealed class TopazFunction : IConvertible, ITopazFunction
 {
     internal ScriptExecutor ScriptExecutor { get; }
 
-    internal string Name { get; private set; }
+    public string Name { get; private set; }
+
+    public int Length => GetArgumentsLength();
+
+    public string this[int index] => GetArgumentName(index);
 
     FunctionDeclaration expr1;
 
@@ -52,7 +56,7 @@ public object Execute(IReadOnlyList<object> args, CancellationToken token)
     {
         token.ThrowIfCancellationRequested();
         var scriptExecutor = ScriptExecutor.NewFunctionInnerBlockScope();
-        var parameters = 
+        var parameters =
             expr1?.Params ??
             expr2?.Params ??
             expr3.Params;
@@ -76,7 +80,7 @@ public object Execute(IReadOnlyList<object> args, CancellationToken token)
                 p = r.Argument;
                 isRest = true;
             }
-            
+
             if (p is ObjectPattern objectPattern)
             {
                 // dont process Object Pattern for missing arguments!
@@ -97,8 +101,8 @@ public object Execute(IReadOnlyList<object> args, CancellationToken token)
             if (isRest)
             {
                 var restLen = args.Count - i;
-                
-                var rested = restLen < 0 ? 
+
+                var rested = restLen < 0 ?
                     Array.Empty<object>() :
                     new object[restLen];
                 for (var j = 0; j < restLen; ++j)
@@ -116,7 +120,7 @@ public object Execute(IReadOnlyList<object> args, CancellationToken token)
                     VariableKind.Var);
             }
         }
-        
+
         var result = scriptExecutor.ExecuteStatement(
             expr1?.Body ??
             expr2?.Body ??
@@ -308,7 +312,7 @@ public object ToType(Type conversionType, IFormatProvider provider)
     {
         if (!conversionType.IsSubclassOf(typeof(Delegate)))
             throw new NotSupportedException();
-        
+
         var topazParameters =
            expr1?.Params ??
            expr2?.Params ??
@@ -324,4 +328,49 @@ public object ToType(Type conversionType, IFormatProvider provider)
         return DynamicDelagateFactory.CreateDynamicDelegate(argTypes, returnType,
             (args) => Execute(args, default), ScriptExecutor.TopazEngine.ValueConverter);
     }
+
+    int GetArgumentsLength()
+    {
+        var parameters =
+            expr1?.Params ??
+            expr2?.Params ??
+            expr3.Params;
+        return parameters.Count;
+    }
+
+    string GetArgumentName(int index)
+    {
+        var parameters =
+            expr1?.Params ??
+            expr2?.Params ??
+            expr3.Params;
+        if (index < 0 || index >= parameters.Count)
+            return null;
+
+        var p = parameters[index];
+        if (p is AssignmentPattern assignmentPattern)
+        {
+            // ex: (x = 1) => x * x
+            p = assignmentPattern.Left;
+        }
+        else if (p is RestElement r)
+        {
+            p = r.Argument;
+        }
+
+        if (p is ObjectPattern)
+        {
+            // Object pattern argument string extraction is not supported!
+            return null;
+        }
+        var id = p as Identifier;
+        if (id == null)
+            return null;
+        return id.Name;
+    }
+
+    public object Invoke(CancellationToken token, params object[] args) => Execute(args, token);
+
+    public ValueTask<object> InvokeAsync(CancellationToken token, params object[] args)
+        => ExecuteAsync(args, token);
 }