LibJS: Add basic Array constructor

We only support Array() with 0 or 1 parameters so far.

Libraries/LibJS/Makefile

@@ -7,6 +7,7 @@ OBJS = \
     Lexer.o \
     Parser.o \
     Runtime/Array.o \
+    Runtime/ArrayConstructor.o \
     Runtime/ArrayPrototype.o \
     Runtime/Cell.o \
     Runtime/ConsoleObject.o \

Libraries/LibJS/Runtime/ArrayConstructor.cpp

@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <AK/Function.h>
+#include <LibJS/Heap/Heap.h>
+#include <LibJS/Interpreter.h>
+#include <LibJS/Runtime/Array.h>
+#include <LibJS/Runtime/ArrayConstructor.h>
+#include <LibJS/Runtime/Shape.h>
+
+namespace JS {
+
+ArrayConstructor::ArrayConstructor()
+{
+    put("prototype", interpreter().array_prototype());
+    put("length", Value(1));
+}
+
+ArrayConstructor::~ArrayConstructor()
+{
+}
+
+Value ArrayConstructor::call(Interpreter& interpreter)
+{
+    if (interpreter.argument_count() == 0)
+        return interpreter.heap().allocate<Array>();
+
+    if (interpreter.argument_count() == 1) {
+        auto* array = interpreter.heap().allocate<Array>();
+        array->elements().resize(interpreter.argument(0).to_i32());
+        return array;
+    }
+
+    // FIXME: Handle "new Array(element0, element1, ...)"
+    ASSERT_NOT_REACHED();
+}
+
+Value ArrayConstructor::construct(Interpreter& interpreter)
+{
+    return call(interpreter);
+}
+
+}

Libraries/LibJS/Runtime/ArrayConstructor.h

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <LibJS/Runtime/NativeFunction.h>
+
+namespace JS {
+
+class ArrayConstructor final : public NativeFunction {
+public:
+    ArrayConstructor();
+    virtual ~ArrayConstructor() override;
+
+    virtual Value call(Interpreter&) override;
+    virtual Value construct(Interpreter&) override;
+
+private:
+    virtual bool has_constructor() const override { return true; }
+    virtual const char* class_name() const override { return "ArrayConstructor"; }
+};
+
+}

Libraries/LibJS/Runtime/ArrayPrototype.cpp

@@ -38,6 +38,7 @@ ArrayPrototype::ArrayPrototype()
     put_native_function("shift", shift);
     put_native_function("pop", pop);
     put_native_function("push", push, 1);
+    put("length", Value(0));
 }
 
 ArrayPrototype::~ArrayPrototype()

Libraries/LibJS/Runtime/GlobalObject.cpp

@@ -2,6 +2,7 @@
 #include <AK/String.h>
 #include <LibJS/Heap/Heap.h>
 #include <LibJS/Interpreter.h>
+#include <LibJS/Runtime/ArrayConstructor.h>
 #include <LibJS/Runtime/ConsoleObject.h>
 #include <LibJS/Runtime/DateConstructor.h>
 #include <LibJS/Runtime/ErrorConstructor.h>
@@ -30,6 +31,7 @@ GlobalObject::GlobalObject()
     put("Function", heap().allocate<FunctionConstructor>());
     put("Math", heap().allocate<MathObject>());
     put("Object", heap().allocate<ObjectConstructor>());
+    put("Array", heap().allocate<ArrayConstructor>());
 }
 
 GlobalObject::~GlobalObject()

Libraries/LibJS/Tests/Array.js

@@ -0,0 +1,16 @@
+function assert(x) { if (!x) throw 1; }
+
+try {
+    assert(Array.length === 1);
+    assert(Array.prototype.length === 0);
+    assert(typeof Array() === "object");
+    assert(typeof new Array() === "object");
+
+    x = new Array(5);
+
+    assert(x.length === 5);
+
+    console.log("PASS");
+} catch (e) {
+    console.log("FAIL: " + e.message);
+}