Some of the code assumed that chars were always signed while that is
not the case on ARM hosts.
Also, some of the code tried to use EOF (-1) in a way similar to what
fgetc() does, however instead of storing the characters in an int
variable a char was used.
While this seemed to work it also meant that character 0xFF would be
incorrectly seen as an end-of-file.
Careful reading of fgetc() reveals that fgetc() stores character
data in an int where valid characters are in the range of 0-255 and
the EOF value is explicitly outside of that range (usually -1).
As mentioned on Discord earlier, we'll add these to all new functions
going forward - this is the backfill. Reasons:
- It makes you look at the spec, implementing based on MDN or V8
behavior is a no-go
- It makes finding the various functions that are non-compliant easier,
in the future everything should either have such a comment or, if it's
not from the spec at all, a comment explaining why that is the case
- It makes it easier to check whether a certain abstract operation is
implemented in LibJS, not all of them use the same name as the spec.
E.g. RejectPromise() is Promise::reject()
- It makes it easier to reason about vm.arguments(), e.g. when the
function has a rest parameter
- It makes it easier to see whether a certain function is from a
proposal or Annex B
Also:
- Add arguments to all functions and abstract operations that already
had a comment
- Fix some outdated section numbers
- Replace some ecma-international.org URLs with tc39.es
While this implementation should be complete it is based on HashMap's
iterator, which currently follows bucket-order instead of the required
insertion order. This can be simply fixed by replacing the underlying
HashMap member in Map with an enhanced one that maintains a linked
list in insertion order.
This will allow us to use these traits for other hash-based containers
(like Map). This commit also adds a special case for negative zero
values, because while the equality check used same_value_zero which is
negative/positive zero insensitive, the hash was not.
This counter is increased each time a synchronous execution sequence
completes, and will allow us to emulate the abstract operations
AddToKeptObjects & ClearKeptObjects efficiently.
This is very similar to Object::define_native_property, but here the
native functions are exported as standalone JS getter and setter
functions, instead of being transparently called by interactions with
the property.
The fact that they *are* subclasses is an implementation detail and
should not be highlighted. The spec calls these NativeErrors, so let's
use that.
Also added a comment explaining *why* they inherit from Error - I was
about to change that :^)
20.5.1.1 Error ( message )
When the Error function is called with argument message, the
following steps are taken:
[...]
3b. Let msgDesc be the PropertyDescriptor {
[[Value]]: msg,
[[Writable]]: true,
[[Enumerable]]: false,
[[Configurable]]: true
}.
3c. Perform ! DefinePropertyOrThrow(O, "message", msgDesc).
The FunctionPrototype is correct for ErrorConstructor itself:
20.5.2 Properties of the Error Constructor
The Error constructor:
- has a [[Prototype]] internal slot whose value is
%Function.prototype%.
However, not for all the other "NativeError" constructors:
20.5.6.2 Properties of the NativeError Constructors
Each NativeError constructor:
- has a [[Prototype]] internal slot whose value is %Error%.
Non-RangeError exceptions can be thrown by user implementations of
valueOf (which are called by to_index), and the specification disallows
changing the type of the thrown error.
The second argument (the default constructor) and the return value have
to be constructors (as a result functions), so we can require that
explicitly by using appropriate types.
