RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-31 12:38:12 +00:00
Code Issues Activity Actions

LibJS: Support array holes, encoded as empty JS::Value

Browse source 
This patch adds a new kind of JS::Value, the empty value.
It's what you get when you do JSValue() (or most commonly, {} in C++.)

An empty Value signifies the absence of a value, and should never be
visible to JavaScript itself. As of right now, it's used for array
holes and as a return value when an exception has been thrown and we
just want to unwind.

This patch is a bit of a mess as I had to fix a whole bunch of code
that was relying on JSValue() being undefined, etc.
This commit is contained in:
Andreas Kling 2020-04-06 20:24:45 +02:00
parent 5495f06af5
commit bdffc9e7fb
9 changed files with 102 additions and 35 deletions
Download patch file Download diff file Expand all files Collapse all files

14
Libraries/LibJS/Runtime/Value.cpp
View file

@ -39,6 +39,14 @@
namespace JS {
Value::Value()
: m_type(Type::Empty)
{
// dbg() << "Create empty value";
// dump_backtrace();
}
bool Value::is_array() const
{
return is_object() && as_object().is_array();
@ -119,6 +127,9 @@ Object* Value::to_object(Heap& heap) const
Value Value::to_number() const
{
switch (m_type) {
case Type::Empty:
ASSERT_NOT_REACHED();
return {};
case Type::Boolean:
return Value(m_value.as_bool ? 1 : 0);
case Type::Number:
@ -280,6 +291,9 @@ Value typed_eq(Value lhs, Value rhs)
return Value(false);
switch (lhs.type()) {
case Value::Type::Empty:
ASSERT_NOT_REACHED();
return {};
case Value::Type::Undefined:
return Value(true);
case Value::Type::Null: