RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-25 21:27:35 +00:00
Code Issues Activity Actions

LibJS: Add function default arguments

Browse source 
Adds the ability for function arguments to have default values. This
works for standard functions as well as arrow functions. Default values
are not printed in a <function>.toString() call, as nodes cannot print
their source string representation.
This commit is contained in:
Matthew Olsson 2020-05-02 11:46:39 -07:00 • committed by Andreas Kling
parent 751f813f6a
commit 5e66f1900b
8 changed files with 184 additions and 35 deletions
Download patch file Download diff file Expand all files Collapse all files

13
Libraries/LibJS/Runtime/FunctionPrototype.cpp
View file

@ -136,9 +136,18 @@ Value FunctionPrototype::to_string(Interpreter& interpreter)
if (this_object->is_native_function() || this_object->is_bound_function()) {
function_body = String::format(" [%s]", this_object->class_name());
} else {
auto& parameters = static_cast<ScriptFunction*>(this_object)->parameters();
StringBuilder parameters_builder;
parameters_builder.join(", ", parameters);
auto first = true;
for (auto& parameter : static_cast<ScriptFunction*>(this_object)->parameters()) {
if (!first)
parameters_builder.append(", ");
first = false;
parameters_builder.append(parameter.name);
if (parameter.default_value) {
// FIXME: See note below
parameters_builder.append(" = TODO");
}
}
function_parameters = parameters_builder.build();
// FIXME: ASTNodes should be able to dump themselves to source strings - something like this:
// auto& body = static_cast<ScriptFunction*>(this_object)->body();

17
Libraries/LibJS/Runtime/ScriptFunction.cpp
View file

@ -46,12 +46,12 @@ static ScriptFunction* script_function_from(Interpreter& interpreter)
return static_cast<ScriptFunction*>(this_object);
}
ScriptFunction* ScriptFunction::create(GlobalObject& global_object, const FlyString& name, const Statement& body, Vector<FlyString> parameters, LexicalEnvironment* parent_environment)
ScriptFunction* ScriptFunction::create(GlobalObject& global_object, const FlyString& name, const Statement& body, Vector<FunctionNode::Parameter> parameters, LexicalEnvironment* parent_environment)
{
return global_object.heap().allocate<ScriptFunction>(name, body, move(parameters), parent_environment, *global_object.function_prototype());
}
ScriptFunction::ScriptFunction(const FlyString& name, const Statement& body, Vector<FlyString> parameters, LexicalEnvironment* parent_environment, Object& prototype)
ScriptFunction::ScriptFunction(const FlyString& name, const Statement& body, Vector<FunctionNode::Parameter> parameters, LexicalEnvironment* parent_environment, Object& prototype)
: Function(prototype)
, m_name(name)
, m_body(body)
@ -77,7 +77,7 @@ LexicalEnvironment* ScriptFunction::create_environment()
{
HashMap<FlyString, Variable> variables;
for (auto& parameter : m_parameters) {
variables.set(parameter, { js_undefined(), DeclarationKind::Var });
variables.set(parameter.name, { js_undefined(), DeclarationKind::Var });
}
if (body().is_scope_node()) {
@ -97,12 +97,15 @@ Value ScriptFunction::call(Interpreter& interpreter)
auto& argument_values = interpreter.call_frame().arguments;
ArgumentVector arguments;
for (size_t i = 0; i < m_parameters.size(); ++i) {
auto name = parameters()[i];
auto parameter = parameters()[i];
auto value = js_undefined();
if (i < argument_values.size())
if (i < argument_values.size() && !argument_values[i].is_undefined()) {
value = argument_values[i];
arguments.append({ name, value });
interpreter.current_environment()->set(name, { value, DeclarationKind::Var });
} else if (parameter.default_value) {
value = parameter.default_value->execute(interpreter);
}
arguments.append({ parameter.name, value });
interpreter.current_environment()->set(parameter.name, { value, DeclarationKind::Var });
}
return interpreter.run(m_body, arguments, ScopeType::Function);
}

9
Libraries/LibJS/Runtime/ScriptFunction.h
View file

@ -26,19 +26,20 @@
#pragma once
#include <LibJS/AST.h>
#include <LibJS/Runtime/Function.h>
namespace JS {
class ScriptFunction final : public Function {
public:
static ScriptFunction* create(GlobalObject&, const FlyString& name, const Statement& body, Vector<FlyString> parameters, LexicalEnvironment* parent_environment);
static ScriptFunction* create(GlobalObject&, const FlyString& name, const Statement& body, Vector<FunctionNode::Parameter> parameters, LexicalEnvironment* parent_environment);
ScriptFunction(const FlyString& name, const Statement& body, Vector<FlyString> parameters, LexicalEnvironment* parent_environment, Object& prototype);
ScriptFunction(const FlyString& name, const Statement& body, Vector<FunctionNode::Parameter> parameters, LexicalEnvironment* parent_environment, Object& prototype);
virtual ~ScriptFunction();
const Statement& body() const { return m_body; }
const Vector<FlyString>& parameters() const { return m_parameters; };
const Vector<FunctionNode::Parameter>& parameters() const { return m_parameters; };
virtual Value call(Interpreter&) override;
virtual Value construct(Interpreter&) override;
@ -56,7 +57,7 @@ private:
FlyString m_name;
NonnullRefPtr<Statement> m_body;
const Vector<FlyString> m_parameters;
const Vector<FunctionNode::Parameter> m_parameters;
LexicalEnvironment* m_parent_environment { nullptr };
};