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ladybird/Libraries/LibJS/Runtime/Object.h

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LibJS: Start building a JavaScript engine for SerenityOS :^) I always tell people to start building things by working on the thing that seems the most interesting right now. The most interesting thing here was an AST + simple interpreter, so that's where we start! There is no lexer or parser yet, we build an AST directly and then execute it in the interpreter, producing a return value. This seems like the start of something interesting. :^)
2020-03-07 19:42:11 +01:00
/*
* 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 <AK/HashMap.h>
LibJS: Loosen type system This commits makes effort towards tolerating some of javascript's quirks when it comes to its type system, note that the interpreter's way of handling type coercion is still not mature at all, for example, we still have to implement NaN instead of just crashing when trying to parse a string and failing.
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#include <AK/String.h>
LibJS: Start building a JavaScript engine for SerenityOS :^) I always tell people to start building things by working on the thing that seems the most interesting right now. The most interesting thing here was an AST + simple interpreter, so that's where we start! There is no lexer or parser yet, we build an AST directly and then execute it in the interpreter, producing a return value. This seems like the start of something interesting. :^)
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#include <LibJS/Forward.h>
LibJS: Add "Heap" and "Runtime" subdirectories Let's try to keep LibJS tidy as it expands. :^)
2020-03-16 14:20:30 +01:00
#include <LibJS/Runtime/Cell.h>
#include <LibJS/Runtime/PrimitiveString.h>
#include <LibJS/Runtime/Value.h>
LibJS: Start building a JavaScript engine for SerenityOS :^) I always tell people to start building things by working on the thing that seems the most interesting right now. The most interesting thing here was an AST + simple interpreter, so that's where we start! There is no lexer or parser yet, we build an AST directly and then execute it in the interpreter, producing a return value. This seems like the start of something interesting. :^)
2020-03-07 19:42:11 +01:00
namespace JS {
LibJS: Add a basic mark&sweep garbage collector :^) Objects can now be allocated via the interpreter's heap. Objects that are allocated in this way will need to be provably reachable from at least one of the known object graph roots. The roots are currently determined by Heap::collect_roots(). Anything that wants be collectable garbage should inherit from Cell, the fundamental atom of the GC heap. This is pretty neat! :^)
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class Object : public Cell {
LibJS: Start building a JavaScript engine for SerenityOS :^) I always tell people to start building things by working on the thing that seems the most interesting right now. The most interesting thing here was an AST + simple interpreter, so that's where we start! There is no lexer or parser yet, we build an AST directly and then execute it in the interpreter, producing a return value. This seems like the start of something interesting. :^)
2020-03-07 19:42:11 +01:00
public:
LibJS: Add a basic mark&sweep garbage collector :^) Objects can now be allocated via the interpreter's heap. Objects that are allocated in this way will need to be provably reachable from at least one of the known object graph roots. The roots are currently determined by Heap::collect_roots(). Anything that wants be collectable garbage should inherit from Cell, the fundamental atom of the GC heap. This is pretty neat! :^)
2020-03-08 19:23:58 +01:00
Object();
virtual ~Object();
LibJS: Start building a JavaScript engine for SerenityOS :^) I always tell people to start building things by working on the thing that seems the most interesting right now. The most interesting thing here was an AST + simple interpreter, so that's where we start! There is no lexer or parser yet, we build an AST directly and then execute it in the interpreter, producing a return value. This seems like the start of something interesting. :^)
2020-03-07 19:42:11 +01:00
LibJS: Allow function calls with missing arguments We were interpreting "undefined" as a variable lookup failure in some cases and throwing a ReferenceError exception instead of treating it as the valid value "undefined". This patch wraps the result of variable lookup in Optional<>, which allows us to only throw ReferenceError when lookup actually fails.
2020-03-27 12:54:18 +01:00
Optional<Value> get(const FlyString& property_name) const;
LibJS: Use FlyString for identifiers This makes variable and property lookups a lot faster since comparing two FlyStrings is O(1).
2020-03-22 11:07:55 +01:00
void put(const FlyString& property_name, Value);
LibJS: Virtualize access to an Object's own properties Object now has virtual get_own_property() and put_own_property() member functions that can be overridden to provide custom behavior. We use these virtuals to move Array-specific access behavior to Array.
2020-03-21 14:37:34 +01:00
LibJS: Use correct |this| value when getting/setting native properties
2020-03-24 14:46:05 +01:00
virtual Optional<Value> get_own_property(const Object& this_object, const FlyString& property_name) const;
virtual bool put_own_property(Object& this_object, const FlyString& property_name, Value);
LibJS: Start building a JavaScript engine for SerenityOS :^) I always tell people to start building things by working on the thing that seems the most interesting right now. The most interesting thing here was an AST + simple interpreter, so that's where we start! There is no lexer or parser yet, we build an AST directly and then execute it in the interpreter, producing a return value. This seems like the start of something interesting. :^)
2020-03-07 19:42:11 +01:00
LibJS: Rework how native functions are called to improve |this| value Native functions now only get the Interpreter& as an argument. They can then extract |this| along with any indexed arguments it wants from it. This forces functions that want |this| to actually deal with calling interpreter.this_value().to_object(), and dealing with the possibility of a non-object |this|. This is still not great but let's keep massaging it forward.
2020-03-28 22:48:35 +01:00
void put_native_function(const FlyString& property_name, AK::Function<Value(Interpreter&)>);
LibJS+LibWeb: Move native properties to separate getters/setters This was a bit cumbersome now, but it gets us closer to a format suited for code generation.
2020-03-29 00:37:33 +01:00
void put_native_property(const FlyString& property_name, AK::Function<Value(Interpreter&)> getter, AK::Function<void(Interpreter&, Value)> setter);
LibJS: Add Object::put_native_function() for convenience This makes it a little bit nicer to add native function properties to JavaScript objects. Thanks to Sergey for suggesting it! :^)
2020-03-13 11:06:32 +01:00
LibJS: Parse ArrayExpression and start implementing Array objects Note that property lookup is not functional yet.
2020-03-20 20:29:57 +01:00
virtual bool is_array() const { return false; }
LibJS: Start implementing Date :^) This adds: - A global Date object (with `length` property and `now` function) - The Date constructor (no arguments yet) - The Date prototype (with `get*` functions)
2020-03-30 00:21:56 +01:00
virtual bool is_date() const { return false; }
virtual bool is_error() const { return false; }
LibJS: Start building a JavaScript engine for SerenityOS :^) I always tell people to start building things by working on the thing that seems the most interesting right now. The most interesting thing here was an AST + simple interpreter, so that's where we start! There is no lexer or parser yet, we build an AST directly and then execute it in the interpreter, producing a return value. This seems like the start of something interesting. :^)
2020-03-07 19:42:11 +01:00
virtual bool is_function() const { return false; }
LibJS: Add NativeFunction, a callable wrapper around a C++ lambda This can be used to implement arbitrary functionality, callable from JavaScript. To make this work, I had to change the way CallExpression passes arguments to the callee. Instead of a HashMap<String, Value>, we now pass an ordered list of Argument { String name; Value value; }. This patch includes a native "print(argument)" function. :^)
2020-03-12 19:53:31 +01:00
virtual bool is_native_function() const { return false; }
LibJS: Add a mechanism for callback-based object properties This patch adds NativeProperty, which can be used to implement object properties that have C++ getters and/or setters. Use this to move String.prototype.length to its correct place. :^)
2020-03-15 18:15:44 +01:00
virtual bool is_native_property() const { return false; }
LibJS: Start implementing Date :^) This adds: - A global Date object (with `length` property and `now` function) - The Date constructor (no arguments yet) - The Date prototype (with `get*` functions)
2020-03-30 00:21:56 +01:00
virtual bool is_string_object() const { return false; }
LibJS: Start building a JavaScript engine for SerenityOS :^) I always tell people to start building things by working on the thing that seems the most interesting right now. The most interesting thing here was an AST + simple interpreter, so that's where we start! There is no lexer or parser yet, we build an AST directly and then execute it in the interpreter, producing a return value. This seems like the start of something interesting. :^)
2020-03-07 19:42:11 +01:00
LibJS: Add a basic mark&sweep garbage collector :^) Objects can now be allocated via the interpreter's heap. Objects that are allocated in this way will need to be provably reachable from at least one of the known object graph roots. The roots are currently determined by Heap::collect_roots(). Anything that wants be collectable garbage should inherit from Cell, the fundamental atom of the GC heap. This is pretty neat! :^)
2020-03-08 19:23:58 +01:00
virtual const char* class_name() const override { return "Object"; }
LibJS: Make the GC marking phase cycle-proof Don't visit cells that are already marked. This prevents the marking phase from looping forever when two cells refer to each other. Also do the marking directly from the CellVisitor, removing another unnecessary phase of the collector. :^)
2020-03-09 22:11:22 +01:00
virtual void visit_children(Cell::Visitor&) override;
LibJS: Start building a JavaScript engine for SerenityOS :^) I always tell people to start building things by working on the thing that seems the most interesting right now. The most interesting thing here was an AST + simple interpreter, so that's where we start! There is no lexer or parser yet, we build an AST directly and then execute it in the interpreter, producing a return value. This seems like the start of something interesting. :^)
2020-03-07 19:42:11 +01:00
LibJS: Add basic prototype support Object will now traverse up the prototype chain when doing a get(). When a function is called on an object, that object will now also be the "this" value inside the function. This stuff is probably not very correct, but we will improve things as we go! :^)
2020-03-15 15:01:10 +01:00
Object* prototype() { return m_prototype; }
const Object* prototype() const { return m_prototype; }
void set_prototype(Object* prototype) { m_prototype = prototype; }
LibJS: Oops, "instanceof" was backwards! Fix the "instanceof" operator to check if the constructor's prototype property occurs anywhere in the prototype chain of the instance object. This patch also adds Object.setPrototypeOf() to make it possible to create a test for this bug. Thanks to DexesTTP for pointing this out! :^)
2020-03-28 19:48:12 +01:00
bool has_prototype(const Object* prototype) const;
LibJS: Add basic prototype support Object will now traverse up the prototype chain when doing a get(). When a function is called on an object, that object will now also be the "this" value inside the function. This stuff is probably not very correct, but we will improve things as we go! :^)
2020-03-15 15:01:10 +01:00
LibJS: Use FlyString for identifiers This makes variable and property lookups a lot faster since comparing two FlyStrings is O(1).
2020-03-22 11:07:55 +01:00
bool has_own_property(const FlyString& property_name) const;
LibJS: Loosen type system This commits makes effort towards tolerating some of javascript's quirks when it comes to its type system, note that the interpreter's way of handling type coercion is still not mature at all, for example, we still have to implement NaN instead of just crashing when trying to parse a string and failing.
2020-03-16 00:19:41 +02:00
enum class PreferredType {
Default,
String,
Number,
};
virtual Value value_of() const { return Value(const_cast<Object*>(this)); }
virtual Value to_primitive(PreferredType preferred_type = PreferredType::Default) const;
virtual Value to_string() const;
LibJS: Add ObjectPrototype and implement hasOwnProperty() All Objects will now have ObjectPrototype as their prototype, unless overridden.
2020-03-15 15:25:43 +01:00
LibJS: Add Object::own_properties() convenience accessor
2020-03-26 12:19:01 +01:00
const HashMap<FlyString, Value>& own_properties() const { return m_properties; }
LibJS: Start building a JavaScript engine for SerenityOS :^) I always tell people to start building things by working on the thing that seems the most interesting right now. The most interesting thing here was an AST + simple interpreter, so that's where we start! There is no lexer or parser yet, we build an AST directly and then execute it in the interpreter, producing a return value. This seems like the start of something interesting. :^)
2020-03-07 19:42:11 +01:00
private:
LibJS: Use FlyString for identifiers This makes variable and property lookups a lot faster since comparing two FlyStrings is O(1).
2020-03-22 11:07:55 +01:00
HashMap<FlyString, Value> m_properties;
LibJS: Add basic prototype support Object will now traverse up the prototype chain when doing a get(). When a function is called on an object, that object will now also be the "this" value inside the function. This stuff is probably not very correct, but we will improve things as we go! :^)
2020-03-15 15:01:10 +01:00
Object* m_prototype { nullptr };
LibJS: Start building a JavaScript engine for SerenityOS :^) I always tell people to start building things by working on the thing that seems the most interesting right now. The most interesting thing here was an AST + simple interpreter, so that's where we start! There is no lexer or parser yet, we build an AST directly and then execute it in the interpreter, producing a return value. This seems like the start of something interesting. :^)
2020-03-07 19:42:11 +01:00
};
}
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