Add support for constructors.

skinny85 · Feb 18, 2024 · 51b591e · 51b591e
1 parent 9ff5126
commit 51b591e
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Showing 3 changed files with 60 additions and 13 deletions.
diff --git a/part-13/src/jmh/java/com/endoflineblog/truffle/part_13/CounterThisBenchmark.java b/part-13/src/jmh/java/com/endoflineblog/truffle/part_13/CounterThisBenchmark.java
@@ -7,8 +7,11 @@ public class CounterThisBenchmark extends TruffleBenchmark {
 
     private static final String COUNTER_CLASS = "" +
             "class Counter { " +
-            "    setCount(count) { " +
-            "        this.count = count; " +
+            "    constructor() { " +
+            "        this.count = 0; " +
+            "    } " +
+            "    increment() { " +
+            "        this.count = this.count + 1; " +
             "    } " +
             "    getCount() { " +
             "        return this.count; " +
@@ -29,8 +32,8 @@ public void setup() {
     private static final String COUNT_WITH_THIS_IN_FOR = "" +
             "function countWithThisInFor(n) { " +
             "    const counter = new Counter(); " +
-            "    for (let i = 1; i <= n; i = i + 1) { " +
-            "        counter['setCount'](i); " +
+            "    for (let i = 0; i < n; i = i + 1) { " +
+            "        counter['increment'](); " +
             "    } " +
             "    return counter['getCount'](); " +
             "}";

diff --git a/part-13/src/main/java/com/endoflineblog/truffle/part_13/nodes/exprs/objects/NewExprNode.java b/part-13/src/main/java/com/endoflineblog/truffle/part_13/nodes/exprs/objects/NewExprNode.java
@@ -2,14 +2,18 @@
 
 import com.endoflineblog.truffle.part_13.exceptions.EasyScriptException;
 import com.endoflineblog.truffle.part_13.nodes.exprs.EasyScriptExprNode;
+import com.endoflineblog.truffle.part_13.nodes.exprs.functions.FunctionDispatchNode;
+import com.endoflineblog.truffle.part_13.nodes.exprs.functions.FunctionDispatchNodeGen;
 import com.endoflineblog.truffle.part_13.runtime.ClassPrototypeObject;
+import com.endoflineblog.truffle.part_13.runtime.FunctionObject;
 import com.endoflineblog.truffle.part_13.runtime.JavaScriptObject;
 import com.oracle.truffle.api.dsl.Executed;
 import com.oracle.truffle.api.dsl.Fallback;
 import com.oracle.truffle.api.dsl.Specialization;
 import com.oracle.truffle.api.frame.VirtualFrame;
+import com.oracle.truffle.api.library.CachedLibrary;
 import com.oracle.truffle.api.nodes.ExplodeLoop;
-import com.oracle.truffle.api.object.Shape;
+import com.oracle.truffle.api.object.DynamicObjectLibrary;
 
 import java.util.List;
 
@@ -24,19 +28,33 @@ public abstract class NewExprNode extends EasyScriptExprNode {
     @Children
     private final EasyScriptExprNode[] args;
 
+    @SuppressWarnings("FieldMayBeFinal")
+    @Child
+    private FunctionDispatchNode constructorDispatchNode;
+
     protected NewExprNode(EasyScriptExprNode constructorExpr, List<EasyScriptExprNode> args) {
         this.constructorExpr = constructorExpr;
         this.args = args.toArray(EasyScriptExprNode[]::new);
+        this.constructorDispatchNode = FunctionDispatchNodeGen.create();
     }
 
     /**
      * The specialization for when the constructor expression evaluates to a
      * {@link ClassPrototypeObject}.
      */
-    @Specialization
-    protected Object instantiateObject(VirtualFrame frame, ClassPrototypeObject classPrototypeObject) {
-        this.consumeArguments(frame);
-        return new JavaScriptObject(this.currentLanguageContext().shapesAndPrototypes.rootShape, classPrototypeObject);
+    @Specialization(limit = "2")
+    protected Object instantiateObject(VirtualFrame frame, ClassPrototypeObject classPrototypeObject,
+            @CachedLibrary("classPrototypeObject") DynamicObjectLibrary dynamicObjectLibrary) {
+        var object = new JavaScriptObject(this.currentLanguageContext().shapesAndPrototypes.rootShape, classPrototypeObject);
+        var constructor = dynamicObjectLibrary.getOrDefault(classPrototypeObject, "constructor", null);
+        if (constructor == null) {
+            this.consumeArguments(frame);
+        } else {
+            var args = this.executeArguments(frame);
+            FunctionObject boundConstructor = (FunctionObject) constructor;
+            this.constructorDispatchNode.executeDispatch(boundConstructor, args, object);
+        }
+        return object;
     }
 
     /**
@@ -60,4 +78,13 @@ private void consumeArguments(VirtualFrame frame) {
             this.args[i].executeGeneric(frame);
         }
     }
+
+    @ExplodeLoop
+    private Object[] executeArguments(VirtualFrame frame) {
+        var args = new Object[this.args.length];
+        for (int i = 0; i < this.args.length; i++) {
+            args[i] = this.args[i].executeGeneric(frame);
+        }
+        return args;
+    }
 }
diff --git a/part-13/src/test/java/com/endoflineblog/truffle/part_13/FieldsTest.java b/part-13/src/test/java/com/endoflineblog/truffle/part_13/FieldsTest.java
@@ -170,17 +170,20 @@ public void benchmark_returns_its_input() {
         var input = 100;
         Value result = this.context.eval("ezs", "" +
                 "class Counter { " +
-                "    setCount(count) { " +
-                "        this.count = count; " +
+                "    constructor() { " +
+                "        this.count = 0; " +
+                "    } " +
+                "    increment() { " +
+                "        this.count = this.count + 1; " +
                 "    } " +
                 "    getCount() { " +
                 "        return this.count; " +
                 "    } " +
                 "} " +
                 "function countWithThisInFor(n) { " +
                 "    const counter = new Counter(); " +
-                "    for (let i = 1; i <= n; i = i + 1) { " +
-                "        counter['setCount'](i); " +
+                "    for (let i = 0; i < n; i = i + 1) { " +
+                "        counter['increment'](); " +
                 "    } " +
                 "    return counter['getCount'](); " +
                 "} " +
@@ -266,4 +269,18 @@ public void negative_array_indexes_are_converted_to_strings() {
         );
         assertEquals(45, result.asInt());
     }
+
+    @Test
+    public void constructors_are_invoked_through_new() {
+        Value result = this.context.eval("ezs", "" +
+                "class A { " +
+                "    constructor(x) { " +
+                "        this.x = x; " +
+                "    } " +
+                "} " +
+                "let a = new A(13); " +
+                "a.x"
+        );
+        assertEquals(13, result.asInt());
+    }
 }