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ladybird/Libraries/LibJS/Interpreter.cpp

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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.
*/
LibJS: Make sure we mark everything reachable from the scope stack This ensures that local variables survive GC.
2020-03-09 21:29:22 +01:00
#include <AK/Badge.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
#include <LibJS/AST.h>
#include <LibJS/Interpreter.h>
LibJS: Add ArrayPrototype and implement Array.prototype.push() This function is ultimately supposed to be generic and allow any |this| that has a length property, but for now it only works on our own Array object type.
2020-03-20 21:01:36 +01:00
#include <LibJS/Runtime/ArrayPrototype.h>
LibJS: Implement basic exception throwing You can now throw exceptions by calling Interpreter::throw_exception(). Anyone who calls ASTNode::execute() needs to check afterwards if the Interpreter now has an exception(), and if so, stop what they're doing and simply return. When catching an exception, we'll first execute the CatchClause node if present. After that, we'll execute the finalizer block if present. This is unlikely to be completely correct, but it's a start! :^)
2020-03-24 14:37:39 +01:00
#include <LibJS/Runtime/Error.h>
#include <LibJS/Runtime/ErrorPrototype.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/GlobalObject.h>
#include <LibJS/Runtime/NativeFunction.h>
#include <LibJS/Runtime/Object.h>
#include <LibJS/Runtime/ObjectPrototype.h>
#include <LibJS/Runtime/StringPrototype.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 {
Interpreter::Interpreter()
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
: m_heap(*this)
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 ObjectPrototype and implement hasOwnProperty() All Objects will now have ObjectPrototype as their prototype, unless overridden.
2020-03-15 15:25:43 +01:00
m_object_prototype = heap().allocate<ObjectPrototype>();
LibJS: Use the same StringPrototype globally To make sure that everyone has the same instance of StringPrototype, hang a global prototype off of the Interpreter that can be fetched when constructing new StringObjects.
2020-03-15 15:11:13 +01:00
m_string_prototype = heap().allocate<StringPrototype>();
LibJS: Add ArrayPrototype and implement Array.prototype.push() This function is ultimately supposed to be generic and allow any |this| that has a length property, but for now it only works on our own Array object type.
2020-03-20 21:01:36 +01:00
m_array_prototype = heap().allocate<ArrayPrototype>();
LibJS: Implement basic exception throwing You can now throw exceptions by calling Interpreter::throw_exception(). Anyone who calls ASTNode::execute() needs to check afterwards if the Interpreter now has an exception(), and if so, stop what they're doing and simply return. When catching an exception, we'll first execute the CatchClause node if present. After that, we'll execute the finalizer block if present. This is unlikely to be completely correct, but it's a start! :^)
2020-03-24 14:37:39 +01:00
m_error_prototype = heap().allocate<ErrorPrototype>();
LibJS: Add a global "Object" constructor This patch adds an "Object" constructor to the global object. The only function it implements so far is Object.getPrototypeOf().
2020-03-28 17:23:54 +01:00
m_global_object = heap().allocate<GlobalObject>();
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
}
Interpreter::~Interpreter()
{
}
LibJS: Implement "else" parsing We can now handle scripts with if/else in LibJS. Most of the changes are about fixing IfStatement to store the consequent and alternate node as Statements. Interpreter now also runs Statements, rather than running ScopeNodes.
2020-03-23 16:46:41 +01:00
Value Interpreter::run(const Statement& statement, Vector<Argument> arguments, ScopeType scope_type)
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: Implement "else" parsing We can now handle scripts with if/else in LibJS. Most of the changes are about fixing IfStatement to store the consequent and alternate node as Statements. Interpreter now also runs Statements, rather than running ScopeNodes.
2020-03-23 16:46:41 +01:00
if (!statement.is_scope_node())
return statement.execute(*this);
auto& block = static_cast<const BlockStatement&>(statement);
enter_scope(block, move(arguments), scope_type);
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
Value last_value = js_undefined();
LibJS: Implement "else" parsing We can now handle scripts with if/else in LibJS. Most of the changes are about fixing IfStatement to store the consequent and alternate node as Statements. Interpreter now also runs Statements, rather than running ScopeNodes.
2020-03-23 16:46:41 +01:00
for (auto& node : block.children()) {
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
last_value = node.execute(*this);
LibJS: Actually leave the current function scope on "return" We now unwind until the nearest function-level scope on the scope stack when executing a return statement.
2020-03-23 19:19:03 +01:00
if (m_unwind_until != ScopeType::None)
break;
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: Actually leave the current function scope on "return" We now unwind until the nearest function-level scope on the scope stack when executing a return statement.
2020-03-23 19:19:03 +01:00
if (m_unwind_until == scope_type)
m_unwind_until = ScopeType::None;
LibJS: Implement "else" parsing We can now handle scripts with if/else in LibJS. Most of the changes are about fixing IfStatement to store the consequent and alternate node as Statements. Interpreter now also runs Statements, rather than running ScopeNodes.
2020-03-23 16:46:41 +01:00
exit_scope(block);
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
return last_value;
}
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
void Interpreter::enter_scope(const ScopeNode& scope_node, Vector<Argument> arguments, ScopeType scope_type)
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: 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, Variable> scope_variables_with_declaration_type;
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
for (auto& argument : arguments) {
scope_variables_with_declaration_type.set(argument.name, { argument.value, DeclarationType::Var });
LibJS: Implement const variable declarations This also tightens the means of redeclaration of a variable by proxy, since we now have a way of knowing how a variable was initially declared, we can check if it was declared using `let` or `const` and not tolerate redeclaration like we did previously.
2020-03-12 14:24:34 +02:00
}
m_scope_stack.append({ scope_type, scope_node, move(scope_variables_with_declaration_type) });
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
}
void Interpreter::exit_scope(const ScopeNode& scope_node)
{
LibJS: Actually pop frames off of the scope stack when exiting a scope
2020-03-27 11:34:58 +01:00
while (!m_scope_stack.is_empty()) {
auto popped_scope = m_scope_stack.take_last();
if (popped_scope.scope_node.ptr() == &scope_node)
break;
}
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: Actually leave the current function scope on "return" We now unwind until the nearest function-level scope on the scope stack when executing a return statement.
2020-03-23 19:19:03 +01:00
// If we unwind all the way, just reset m_unwind_until so that future "return" doesn't break.
if (m_scope_stack.is_empty())
m_unwind_until = ScopeType::None;
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: 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 Interpreter::declare_variable(const FlyString& name, DeclarationType declaration_type)
LibJS: Add basic support for (scoped) variables It's now possible to assign expressions to variables. The variables are put into the current scope of the interpreter. Variable lookup follows the scope chain, ending in the global object.
2020-03-09 21:13:55 +01:00
{
LibJS: Allow the choice of a scope of declaration for a variable (#1408) Previously, we were assuming all declared variables were bound to a block scope, now, with the addition of declaration types, we can bind a variable to a block scope using `let`, or a function scope (the scope of the inner-most enclosing function of a `var` declaration) using `var`.
2020-03-11 21:09:20 +02:00
switch (declaration_type) {
case DeclarationType::Var:
for (ssize_t i = m_scope_stack.size() - 1; i >= 0; --i) {
auto& scope = m_scope_stack.at(i);
if (scope.type == ScopeType::Function) {
LibJS: Implement const variable declarations This also tightens the means of redeclaration of a variable by proxy, since we now have a way of knowing how a variable was initially declared, we can check if it was declared using `let` or `const` and not tolerate redeclaration like we did previously.
2020-03-12 14:24:34 +02:00
if (scope.variables.get(name).has_value() && scope.variables.get(name).value().declaration_type != DeclarationType::Var)
ASSERT_NOT_REACHED();
scope.variables.set(move(name), { js_undefined(), declaration_type });
LibJS: Allow the choice of a scope of declaration for a variable (#1408) Previously, we were assuming all declared variables were bound to a block scope, now, with the addition of declaration types, we can bind a variable to a block scope using `let`, or a function scope (the scope of the inner-most enclosing function of a `var` declaration) using `var`.
2020-03-11 21:09:20 +02:00
return;
}
}
global_object().put(move(name), js_undefined());
break;
case DeclarationType::Let:
LibJS: Implement const variable declarations This also tightens the means of redeclaration of a variable by proxy, since we now have a way of knowing how a variable was initially declared, we can check if it was declared using `let` or `const` and not tolerate redeclaration like we did previously.
2020-03-12 14:24:34 +02:00
case DeclarationType::Const:
LibJS: Don't allow the redeclaration of a `var` variable using let/const Previously, we were allowing the redeclaration of a variable with `let` or `const` if it was declared initially using `var`, we should not tolerate any form of variable redeclaration using let/const.
2020-03-13 20:16:37 +02:00
if (m_scope_stack.last().variables.get(name).has_value())
LibJS: Implement const variable declarations This also tightens the means of redeclaration of a variable by proxy, since we now have a way of knowing how a variable was initially declared, we can check if it was declared using `let` or `const` and not tolerate redeclaration like we did previously.
2020-03-12 14:24:34 +02:00
ASSERT_NOT_REACHED();
m_scope_stack.last().variables.set(move(name), { js_undefined(), declaration_type });
LibJS: Allow the choice of a scope of declaration for a variable (#1408) Previously, we were assuming all declared variables were bound to a block scope, now, with the addition of declaration types, we can bind a variable to a block scope using `let`, or a function scope (the scope of the inner-most enclosing function of a `var` declaration) using `var`.
2020-03-11 21:09:20 +02:00
break;
}
LibJS: Add basic support for (scoped) variables It's now possible to assign expressions to variables. The variables are put into the current scope of the interpreter. Variable lookup follows the scope chain, ending in the global object.
2020-03-09 21:13:55 +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
void Interpreter::set_variable(const FlyString& name, Value value, bool first_assignment)
LibJS: Add basic support for (scoped) variables It's now possible to assign expressions to variables. The variables are put into the current scope of the interpreter. Variable lookup follows the scope chain, ending in the global object.
2020-03-09 21:13:55 +01:00
{
for (ssize_t i = m_scope_stack.size() - 1; i >= 0; --i) {
auto& scope = m_scope_stack.at(i);
LibJS: Implement const variable declarations This also tightens the means of redeclaration of a variable by proxy, since we now have a way of knowing how a variable was initially declared, we can check if it was declared using `let` or `const` and not tolerate redeclaration like we did previously.
2020-03-12 14:24:34 +02:00
auto possible_match = scope.variables.get(name);
if (possible_match.has_value()) {
LibJS: Fix assignment of const variable on declaration We were previously assuming that we were reassigning a variable even when we were not, oops, my bad. :/
2020-03-15 23:57:54 +02:00
if (!first_assignment && possible_match.value().declaration_type == DeclarationType::Const)
LibJS: Implement const variable declarations This also tightens the means of redeclaration of a variable by proxy, since we now have a way of knowing how a variable was initially declared, we can check if it was declared using `let` or `const` and not tolerate redeclaration like we did previously.
2020-03-12 14:24:34 +02:00
ASSERT_NOT_REACHED();
scope.variables.set(move(name), { move(value), possible_match.value().declaration_type });
LibJS: Add basic support for (scoped) variables It's now possible to assign expressions to variables. The variables are put into the current scope of the interpreter. Variable lookup follows the scope chain, ending in the global object.
2020-03-09 21:13:55 +01:00
return;
}
}
global_object().put(move(name), move(value));
}
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> Interpreter::get_variable(const FlyString& name)
LibJS: Add basic support for (scoped) variables It's now possible to assign expressions to variables. The variables are put into the current scope of the interpreter. Variable lookup follows the scope chain, ending in the global object.
2020-03-09 21:13:55 +01:00
{
LibJS: Make it possible to reference the "this" value in JavaScript
2020-03-28 16:32:46 +01:00
if (name == "this")
return this_value();
LibJS: Add basic support for (scoped) variables It's now possible to assign expressions to variables. The variables are put into the current scope of the interpreter. Variable lookup follows the scope chain, ending in the global object.
2020-03-09 21:13:55 +01:00
for (ssize_t i = m_scope_stack.size() - 1; i >= 0; --i) {
auto& scope = m_scope_stack.at(i);
auto value = scope.variables.get(name);
if (value.has_value())
LibJS: Implement const variable declarations This also tightens the means of redeclaration of a variable by proxy, since we now have a way of knowing how a variable was initially declared, we can check if it was declared using `let` or `const` and not tolerate redeclaration like we did previously.
2020-03-12 14:24:34 +02:00
return value.value().value;
LibJS: Add basic support for (scoped) variables It's now possible to assign expressions to variables. The variables are put into the current scope of the interpreter. Variable lookup follows the scope chain, ending in the global object.
2020-03-09 21:13:55 +01:00
}
return global_object().get(name);
}
LibJS: Rename collect_roots() => gather_roots() Since this is about finding the things we should *not* garabge collect, it seemed wrong to call it "collect_something" :^)
2020-03-15 15:12:34 +01:00
void Interpreter::gather_roots(Badge<Heap>, HashTable<Cell*>& roots)
LibJS: Make sure we mark everything reachable from the scope stack This ensures that local variables survive GC.
2020-03-09 21:29:22 +01:00
{
roots.set(m_global_object);
LibJS: Use the same StringPrototype globally To make sure that everyone has the same instance of StringPrototype, hang a global prototype off of the Interpreter that can be fetched when constructing new StringObjects.
2020-03-15 15:11:13 +01:00
roots.set(m_string_prototype);
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
roots.set(m_object_prototype);
LibJS: Add ArrayPrototype and implement Array.prototype.push() This function is ultimately supposed to be generic and allow any |this| that has a length property, but for now it only works on our own Array object type.
2020-03-20 21:01:36 +01:00
roots.set(m_array_prototype);
LibJS: Implement basic exception throwing You can now throw exceptions by calling Interpreter::throw_exception(). Anyone who calls ASTNode::execute() needs to check afterwards if the Interpreter now has an exception(), and if so, stop what they're doing and simply return. When catching an exception, we'll first execute the CatchClause node if present. After that, we'll execute the finalizer block if present. This is unlikely to be completely correct, but it's a start! :^)
2020-03-24 14:37:39 +01:00
roots.set(m_error_prototype);
roots.set(m_exception);
LibJS: Make sure we mark everything reachable from the scope stack This ensures that local variables survive GC.
2020-03-09 21:29:22 +01:00
for (auto& scope : m_scope_stack) {
for (auto& it : scope.variables) {
LibJS: Implement const variable declarations This also tightens the means of redeclaration of a variable by proxy, since we now have a way of knowing how a variable was initially declared, we can check if it was declared using `let` or `const` and not tolerate redeclaration like we did previously.
2020-03-12 14:24:34 +02:00
if (it.value.value.is_cell())
roots.set(it.value.value.as_cell());
LibJS: Make sure we mark everything reachable from the scope stack This ensures that local variables survive GC.
2020-03-09 21:29:22 +01:00
}
}
LibJS: Interpreter should make sure that the "this" stack gets marked
2020-03-15 15:07:49 +01:00
LibJS: Protect function call "this" and arguments from GC This patch adds a CallFrame stack to Interpreter, which keeps track of the "this" value and all argument values passed in function calls. Interpreter::gather_roots() scans the call stack, making sure that all argument values get marked. :^)
2020-03-17 11:00:09 +01:00
for (auto& call_frame : m_call_stack) {
if (call_frame.this_value.is_cell())
roots.set(call_frame.this_value.as_cell());
for (auto& argument : call_frame.arguments) {
if (argument.is_cell())
roots.set(argument.as_cell());
}
LibJS: Interpreter should make sure that the "this" stack gets marked
2020-03-15 15:07:49 +01:00
}
LibJS: Make sure we mark everything reachable from the scope stack This ensures that local variables survive GC.
2020-03-09 21:29:22 +01:00
}
LibJS: Add Interpreter::call(Function*, this_value, arguments) This helper function takes care of pushing/popping a call frame so you don't need to worry about it.
2020-03-18 15:20:49 +01:00
Value Interpreter::call(Function* function, Value this_value, const Vector<Value>& arguments)
{
auto& call_frame = push_call_frame();
call_frame.this_value = this_value;
call_frame.arguments = arguments;
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
auto result = function->call(*this);
LibJS: Add Interpreter::call(Function*, this_value, arguments) This helper function takes care of pushing/popping a call frame so you don't need to worry about it.
2020-03-18 15:20:49 +01:00
pop_call_frame();
return result;
}
LibJS: Implement "throw" You can now throw an expression to the nearest catcher! :^) To support throwing arbitrary values, I added an Exception class that sits as a wrapper around whatever is thrown. In the future it will be a logical place to store a call stack.
2020-03-24 22:03:50 +01:00
Value Interpreter::throw_exception(Exception* exception)
LibJS: Implement basic exception throwing You can now throw exceptions by calling Interpreter::throw_exception(). Anyone who calls ASTNode::execute() needs to check afterwards if the Interpreter now has an exception(), and if so, stop what they're doing and simply return. When catching an exception, we'll first execute the CatchClause node if present. After that, we'll execute the finalizer block if present. This is unlikely to be completely correct, but it's a start! :^)
2020-03-24 14:37:39 +01:00
{
m_exception = exception;
unwind(ScopeType::Try);
return {};
}
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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