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ladybird/Userland/Libraries/LibJS/Runtime/DeclarativeEnvironmentRecord.h

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LibJS: Introduce LexicalEnvironment This patch replaces the old variable lookup logic with a new one based on lexical environments. This brings us closer to the way JavaScript is actually specced, and also gives us some basic support for closures. The interpreter's call stack frames now have a pointer to the lexical environment for that frame. Each lexical environment can have a chain of parent environments. Before calling a Function, we first ask it to create_environment(). This gives us a new LexicalEnvironment for that function, which has the function's lexical parent's environment as its parent. This allows inner functions to access variables in their outer function: function foo() { <-- LexicalEnvironment A var x = 1; function() { <-- LexicalEnvironment B (parent: A) console.log(x); } } If we return the result of a function expression from a function, that new function object will keep a reference to its parent environment, which is how we get closures. :^) I'm pretty sure I didn't get everything right here, but it's a pretty good start. This is quite a bit slower than before, but also correcter!
2020-04-15 21:58:22 +02:00
/*
LibJS: Rename Environment Records so they match the spec :^) This patch makes the following name changes: - ScopeObject => EnvironmentRecord - LexicalEnvironment => DeclarativeEnvironmentRecord - WithScope => ObjectEnvironmentRecord
2021-06-21 23:17:24 +02:00
* Copyright (c) 2020-2021, Andreas Kling <kling@serenityos.org>
LibJS: Introduce LexicalEnvironment This patch replaces the old variable lookup logic with a new one based on lexical environments. This brings us closer to the way JavaScript is actually specced, and also gives us some basic support for closures. The interpreter's call stack frames now have a pointer to the lexical environment for that frame. Each lexical environment can have a chain of parent environments. Before calling a Function, we first ask it to create_environment(). This gives us a new LexicalEnvironment for that function, which has the function's lexical parent's environment as its parent. This allows inner functions to access variables in their outer function: function foo() { <-- LexicalEnvironment A var x = 1; function() { <-- LexicalEnvironment B (parent: A) console.log(x); } } If we return the result of a function expression from a function, that new function object will keep a reference to its parent environment, which is how we get closures. :^) I'm pretty sure I didn't get everything right here, but it's a pretty good start. This is quite a bit slower than before, but also correcter!
2020-04-15 21:58:22 +02:00
*
Everything: Move to SPDX license identifiers in all files. SPDX License Identifiers are a more compact / standardized way of representing file license information. See: https://spdx.dev/resources/use/#identifiers This was done with the `ambr` search and replace tool. ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
2021-04-22 01:24:48 -07:00
* SPDX-License-Identifier: BSD-2-Clause
LibJS: Introduce LexicalEnvironment This patch replaces the old variable lookup logic with a new one based on lexical environments. This brings us closer to the way JavaScript is actually specced, and also gives us some basic support for closures. The interpreter's call stack frames now have a pointer to the lexical environment for that frame. Each lexical environment can have a chain of parent environments. Before calling a Function, we first ask it to create_environment(). This gives us a new LexicalEnvironment for that function, which has the function's lexical parent's environment as its parent. This allows inner functions to access variables in their outer function: function foo() { <-- LexicalEnvironment A var x = 1; function() { <-- LexicalEnvironment B (parent: A) console.log(x); } } If we return the result of a function expression from a function, that new function object will keep a reference to its parent environment, which is how we get closures. :^) I'm pretty sure I didn't get everything right here, but it's a pretty good start. This is quite a bit slower than before, but also correcter!
2020-04-15 21:58:22 +02:00
*/
#pragma once
#include <AK/FlyString.h>
#include <AK/HashMap.h>
LibJS: Rename Environment Records so they match the spec :^) This patch makes the following name changes: - ScopeObject => EnvironmentRecord - LexicalEnvironment => DeclarativeEnvironmentRecord - WithScope => ObjectEnvironmentRecord
2021-06-21 23:17:24 +02:00
#include <LibJS/Runtime/EnvironmentRecord.h>
LibJS: Introduce LexicalEnvironment This patch replaces the old variable lookup logic with a new one based on lexical environments. This brings us closer to the way JavaScript is actually specced, and also gives us some basic support for closures. The interpreter's call stack frames now have a pointer to the lexical environment for that frame. Each lexical environment can have a chain of parent environments. Before calling a Function, we first ask it to create_environment(). This gives us a new LexicalEnvironment for that function, which has the function's lexical parent's environment as its parent. This allows inner functions to access variables in their outer function: function foo() { <-- LexicalEnvironment A var x = 1; function() { <-- LexicalEnvironment B (parent: A) console.log(x); } } If we return the result of a function expression from a function, that new function object will keep a reference to its parent environment, which is how we get closures. :^) I'm pretty sure I didn't get everything right here, but it's a pretty good start. This is quite a bit slower than before, but also correcter!
2020-04-15 21:58:22 +02:00
#include <LibJS/Runtime/Value.h>
namespace JS {
LibJS: Rename Environment Records so they match the spec :^) This patch makes the following name changes: - ScopeObject => EnvironmentRecord - LexicalEnvironment => DeclarativeEnvironmentRecord - WithScope => ObjectEnvironmentRecord
2021-06-21 23:17:24 +02:00
class DeclarativeEnvironmentRecord final : public EnvironmentRecord {
JS_OBJECT(DeclarativeEnvironmentRecord, EnvironmentRecord);
LibJS: Introduce LexicalEnvironment This patch replaces the old variable lookup logic with a new one based on lexical environments. This brings us closer to the way JavaScript is actually specced, and also gives us some basic support for closures. The interpreter's call stack frames now have a pointer to the lexical environment for that frame. Each lexical environment can have a chain of parent environments. Before calling a Function, we first ask it to create_environment(). This gives us a new LexicalEnvironment for that function, which has the function's lexical parent's environment as its parent. This allows inner functions to access variables in their outer function: function foo() { <-- LexicalEnvironment A var x = 1; function() { <-- LexicalEnvironment B (parent: A) console.log(x); } } If we return the result of a function expression from a function, that new function object will keep a reference to its parent environment, which is how we get closures. :^) I'm pretty sure I didn't get everything right here, but it's a pretty good start. This is quite a bit slower than before, but also correcter!
2020-04-15 21:58:22 +02:00
public:
LibJS: Initial class implementation; allow super expressions in object literal methods; add EnvrionmentRecord fields and methods to LexicalEnvironment Adding EnvrionmentRecord's fields and methods lets us throw an exception when |this| is not initialized, which occurs when the super constructor in a derived class has not yet been called, or when |this| has already been initialized (the super constructor was already called).
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enum class ThisBindingStatus {
Lexical,
Initialized,
Uninitialized,
};
enum class EnvironmentRecordType {
Declarative,
Function,
Object,
Module,
};
LibJS: Rename Environment Records so they match the spec :^) This patch makes the following name changes: - ScopeObject => EnvironmentRecord - LexicalEnvironment => DeclarativeEnvironmentRecord - WithScope => ObjectEnvironmentRecord
2021-06-21 23:17:24 +02:00
DeclarativeEnvironmentRecord();
DeclarativeEnvironmentRecord(EnvironmentRecordType);
DeclarativeEnvironmentRecord(HashMap<FlyString, Variable> variables, EnvironmentRecord* parent_scope);
DeclarativeEnvironmentRecord(HashMap<FlyString, Variable> variables, EnvironmentRecord* parent_scope, EnvironmentRecordType);
virtual ~DeclarativeEnvironmentRecord() override;
LibJS: Introduce LexicalEnvironment This patch replaces the old variable lookup logic with a new one based on lexical environments. This brings us closer to the way JavaScript is actually specced, and also gives us some basic support for closures. The interpreter's call stack frames now have a pointer to the lexical environment for that frame. Each lexical environment can have a chain of parent environments. Before calling a Function, we first ask it to create_environment(). This gives us a new LexicalEnvironment for that function, which has the function's lexical parent's environment as its parent. This allows inner functions to access variables in their outer function: function foo() { <-- LexicalEnvironment A var x = 1; function() { <-- LexicalEnvironment B (parent: A) console.log(x); } } If we return the result of a function expression from a function, that new function object will keep a reference to its parent environment, which is how we get closures. :^) I'm pretty sure I didn't get everything right here, but it's a pretty good start. This is quite a bit slower than before, but also correcter!
2020-04-15 21:58:22 +02:00
LibJS: Rename Environment Records so they match the spec :^) This patch makes the following name changes: - ScopeObject => EnvironmentRecord - LexicalEnvironment => DeclarativeEnvironmentRecord - WithScope => ObjectEnvironmentRecord
2021-06-21 23:17:24 +02:00
// ^EnvironmentRecord
LibJS: Convert EnvironmentRecord & friends to east-const style
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virtual Optional<Variable> get_from_scope(FlyString const&) const override;
virtual void put_to_scope(FlyString const&, Variable) override;
LibJS: Support deleting local variables with operator delete To make this cleaner i also moved the logic into Reference::delete_.
2021-06-08 04:00:53 +03:00
virtual bool delete_from_scope(FlyString const&) override;
LibJS: Add a scope object abstraction Both GlobalObject and LexicalEnvironment now inherit from ScopeObject, and the VM's call frames point to a ScopeObject chain rather than just a LexicalEnvironment chain. This gives us much more flexibility to implement things like "with", and also unifies some of the code paths that previously required special handling of the global object. There's a bunch of more cleanup that can be done in the wake of this change, and there might be some oversights in the handling of the "super" keyword, but this generally seems like a good architectural improvement. :^)
2020-11-28 16:02:27 +01:00
virtual bool has_this_binding() const override;
virtual Value get_this_binding(GlobalObject&) const override;
LibJS: Introduce LexicalEnvironment This patch replaces the old variable lookup logic with a new one based on lexical environments. This brings us closer to the way JavaScript is actually specced, and also gives us some basic support for closures. The interpreter's call stack frames now have a pointer to the lexical environment for that frame. Each lexical environment can have a chain of parent environments. Before calling a Function, we first ask it to create_environment(). This gives us a new LexicalEnvironment for that function, which has the function's lexical parent's environment as its parent. This allows inner functions to access variables in their outer function: function foo() { <-- LexicalEnvironment A var x = 1; function() { <-- LexicalEnvironment B (parent: A) console.log(x); } } If we return the result of a function expression from a function, that new function object will keep a reference to its parent environment, which is how we get closures. :^) I'm pretty sure I didn't get everything right here, but it's a pretty good start. This is quite a bit slower than before, but also correcter!
2020-04-15 21:58:22 +02:00
LibJS: Convert EnvironmentRecord & friends to east-const style
2021-06-21 23:26:50 +02:00
HashMap<FlyString, Variable> const& variables() const { return m_variables; }
LibJS: Introduce LexicalEnvironment This patch replaces the old variable lookup logic with a new one based on lexical environments. This brings us closer to the way JavaScript is actually specced, and also gives us some basic support for closures. The interpreter's call stack frames now have a pointer to the lexical environment for that frame. Each lexical environment can have a chain of parent environments. Before calling a Function, we first ask it to create_environment(). This gives us a new LexicalEnvironment for that function, which has the function's lexical parent's environment as its parent. This allows inner functions to access variables in their outer function: function foo() { <-- LexicalEnvironment A var x = 1; function() { <-- LexicalEnvironment B (parent: A) console.log(x); } } If we return the result of a function expression from a function, that new function object will keep a reference to its parent environment, which is how we get closures. :^) I'm pretty sure I didn't get everything right here, but it's a pretty good start. This is quite a bit slower than before, but also correcter!
2020-04-15 21:58:22 +02:00
LibJS: Initial class implementation; allow super expressions in object literal methods; add EnvrionmentRecord fields and methods to LexicalEnvironment Adding EnvrionmentRecord's fields and methods lets us throw an exception when |this| is not initialized, which occurs when the super constructor in a derived class has not yet been called, or when |this| has already been initialized (the super constructor was already called).
2020-06-08 13:31:21 -05:00
void set_home_object(Value object) { m_home_object = object; }
bool has_super_binding() const;
Value get_super_base();
ThisBindingStatus this_binding_status() const { return m_this_binding_status; }
LibJS: Reduce use of Interpreter in LexicalEnvironment
2020-09-29 16:41:28 +02:00
void bind_this_value(GlobalObject&, Value this_value);
LibJS: Initial class implementation; allow super expressions in object literal methods; add EnvrionmentRecord fields and methods to LexicalEnvironment Adding EnvrionmentRecord's fields and methods lets us throw an exception when |this| is not initialized, which occurs when the super constructor in a derived class has not yet been called, or when |this| has already been initialized (the super constructor was already called).
2020-06-08 13:31:21 -05:00
// Not a standard operation.
void replace_this_binding(Value this_value) { m_this_value = this_value; }
Value new_target() const { return m_new_target; };
void set_new_target(Value new_target) { m_new_target = new_target; }
Function* current_function() const { return m_current_function; }
void set_current_function(Function& function) { m_current_function = &function; }
LibJS: Move most of Interpreter into VM This patch moves the exception state, call stack and scope stack from Interpreter to VM. I'm doing this to help myself discover what the split between Interpreter and VM should be, by shuffling things around and seeing what falls where. With these changes, we no longer have a persistent lexical environment for the current global object on the Interpreter's call stack. Instead, we push/pop that environment on Interpreter::run() enter/exit. Since it should only be used to find the global "this", and not for variable storage (that goes directly into the global object instead!), I had to insert some short-circuiting when walking the environment parent chain during variable lookup. Note that this is a "stepping stone" commit, not a final design.
2020-09-27 15:18:55 +02:00
EnvironmentRecordType type() const { return m_environment_record_type; }
LibJS: Introduce LexicalEnvironment This patch replaces the old variable lookup logic with a new one based on lexical environments. This brings us closer to the way JavaScript is actually specced, and also gives us some basic support for closures. The interpreter's call stack frames now have a pointer to the lexical environment for that frame. Each lexical environment can have a chain of parent environments. Before calling a Function, we first ask it to create_environment(). This gives us a new LexicalEnvironment for that function, which has the function's lexical parent's environment as its parent. This allows inner functions to access variables in their outer function: function foo() { <-- LexicalEnvironment A var x = 1; function() { <-- LexicalEnvironment B (parent: A) console.log(x); } } If we return the result of a function expression from a function, that new function object will keep a reference to its parent environment, which is how we get closures. :^) I'm pretty sure I didn't get everything right here, but it's a pretty good start. This is quite a bit slower than before, but also correcter!
2020-04-15 21:58:22 +02:00
private:
LibJS: Rename Environment Records so they match the spec :^) This patch makes the following name changes: - ScopeObject => EnvironmentRecord - LexicalEnvironment => DeclarativeEnvironmentRecord - WithScope => ObjectEnvironmentRecord
2021-06-21 23:17:24 +02:00
virtual bool is_declarative_environment_record() const override { return true; }
LibJS: Rename Cell::visit_children() => Cell::visit_edges() The GC heap is really a graph of cells, so "children" didn't quite feel appropriate here.
2020-11-28 14:33:36 +01:00
virtual void visit_edges(Visitor&) override;
LibJS: Introduce LexicalEnvironment This patch replaces the old variable lookup logic with a new one based on lexical environments. This brings us closer to the way JavaScript is actually specced, and also gives us some basic support for closures. The interpreter's call stack frames now have a pointer to the lexical environment for that frame. Each lexical environment can have a chain of parent environments. Before calling a Function, we first ask it to create_environment(). This gives us a new LexicalEnvironment for that function, which has the function's lexical parent's environment as its parent. This allows inner functions to access variables in their outer function: function foo() { <-- LexicalEnvironment A var x = 1; function() { <-- LexicalEnvironment B (parent: A) console.log(x); } } If we return the result of a function expression from a function, that new function object will keep a reference to its parent environment, which is how we get closures. :^) I'm pretty sure I didn't get everything right here, but it's a pretty good start. This is quite a bit slower than before, but also correcter!
2020-04-15 21:58:22 +02:00
LibJS: Shrink sizeof(LexicalEnvironment) by reorganizing members
2020-10-22 17:03:40 +02:00
EnvironmentRecordType m_environment_record_type : 8 { EnvironmentRecordType::Declarative };
ThisBindingStatus m_this_binding_status : 8 { ThisBindingStatus::Uninitialized };
LibJS: Introduce LexicalEnvironment This patch replaces the old variable lookup logic with a new one based on lexical environments. This brings us closer to the way JavaScript is actually specced, and also gives us some basic support for closures. The interpreter's call stack frames now have a pointer to the lexical environment for that frame. Each lexical environment can have a chain of parent environments. Before calling a Function, we first ask it to create_environment(). This gives us a new LexicalEnvironment for that function, which has the function's lexical parent's environment as its parent. This allows inner functions to access variables in their outer function: function foo() { <-- LexicalEnvironment A var x = 1; function() { <-- LexicalEnvironment B (parent: A) console.log(x); } } If we return the result of a function expression from a function, that new function object will keep a reference to its parent environment, which is how we get closures. :^) I'm pretty sure I didn't get everything right here, but it's a pretty good start. This is quite a bit slower than before, but also correcter!
2020-04-15 21:58:22 +02:00
HashMap<FlyString, Variable> m_variables;
LibJS: Initial class implementation; allow super expressions in object literal methods; add EnvrionmentRecord fields and methods to LexicalEnvironment Adding EnvrionmentRecord's fields and methods lets us throw an exception when |this| is not initialized, which occurs when the super constructor in a derived class has not yet been called, or when |this| has already been initialized (the super constructor was already called).
2020-06-08 13:31:21 -05:00
Value m_home_object;
Value m_this_value;
Value m_new_target;
// Corresponds to [[FunctionObject]]
Function* m_current_function { nullptr };
LibJS: Introduce LexicalEnvironment This patch replaces the old variable lookup logic with a new one based on lexical environments. This brings us closer to the way JavaScript is actually specced, and also gives us some basic support for closures. The interpreter's call stack frames now have a pointer to the lexical environment for that frame. Each lexical environment can have a chain of parent environments. Before calling a Function, we first ask it to create_environment(). This gives us a new LexicalEnvironment for that function, which has the function's lexical parent's environment as its parent. This allows inner functions to access variables in their outer function: function foo() { <-- LexicalEnvironment A var x = 1; function() { <-- LexicalEnvironment B (parent: A) console.log(x); } } If we return the result of a function expression from a function, that new function object will keep a reference to its parent environment, which is how we get closures. :^) I'm pretty sure I didn't get everything right here, but it's a pretty good start. This is quite a bit slower than before, but also correcter!
2020-04-15 21:58:22 +02:00
};
LibJS: Add a bunch of fast_is<T> to avoid slow RTTI in hot code
2021-06-13 11:23:23 +02:00
template<>
LibJS: Rename Environment Records so they match the spec :^) This patch makes the following name changes: - ScopeObject => EnvironmentRecord - LexicalEnvironment => DeclarativeEnvironmentRecord - WithScope => ObjectEnvironmentRecord
2021-06-21 23:17:24 +02:00
inline bool Object::fast_is<DeclarativeEnvironmentRecord>() const { return is_declarative_environment_record(); }
LibJS: Add a bunch of fast_is<T> to avoid slow RTTI in hot code
2021-06-13 11:23:23 +02:00
LibJS: Introduce LexicalEnvironment This patch replaces the old variable lookup logic with a new one based on lexical environments. This brings us closer to the way JavaScript is actually specced, and also gives us some basic support for closures. The interpreter's call stack frames now have a pointer to the lexical environment for that frame. Each lexical environment can have a chain of parent environments. Before calling a Function, we first ask it to create_environment(). This gives us a new LexicalEnvironment for that function, which has the function's lexical parent's environment as its parent. This allows inner functions to access variables in their outer function: function foo() { <-- LexicalEnvironment A var x = 1; function() { <-- LexicalEnvironment B (parent: A) console.log(x); } } If we return the result of a function expression from a function, that new function object will keep a reference to its parent environment, which is how we get closures. :^) I'm pretty sure I didn't get everything right here, but it's a pretty good start. This is quite a bit slower than before, but also correcter!
2020-04-15 21:58:22 +02:00
}
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