This patch adds JS::Shape, which implements a transition tree for our
Object class. Object property keys, prototypes and attributes are now
stored in a Shape, and each Object has a Shape.
When adding a property to an Object, we make a transition from the old
Shape to a new Shape. If we've made the same exact transition in the
past (with another Object), we reuse the same transition and both
objects may now share a Shape.
This will become the foundation of inline caching and other engine
optimizations in the future. :^)
This adds:
- A global Date object (with `length` property and `now` function)
- The Date constructor (no arguments yet)
- The Date prototype (with `get*` functions)
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.
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! :^)
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.
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! :^)
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.
