This includes:
- Parsing proper LabelledStatements with try_parse_labelled_statement()
- Removing LabelableStatement
- Implementing the LoopEvaluation semantics via loop_evaluation() in
each IterationStatement subclass; and IterationStatement evaluation
via {For,ForIn,ForOf,ForAwaitOf,While,DoWhile}Statement::execute()
- Updating ReturnStatement, BreakStatement and ContinueStatement to
return the appropriate completion types
- Basically reimplementing TryStatement and SwitchStatement according to
the spec, using completions
- Honoring result completion types in AsyncBlockStart and
OrdinaryCallEvaluateBody
- Removing any uses of the VM unwind mechanism - most importantly,
VM::throw_exception() now exclusively sets an exception and no longer
triggers any unwinding mechanism.
However, we already did a good job updating all of LibWeb and userland
applications to not use it, and the few remaining uses elsewhere don't
rely on unwinding AFAICT.
This fixes all failing Date.UTC test262 tests, which failed due to not
handling invalid input and evaluating inputs out of order. But this also
avoids using timegm(), which doesn't work on macOS for years before 1900
(they simply return -1 for those years).
Partially addresses #4651. Date.parse.js still fails.
We currently use Core::DateTime create, which internally uses mktime().
This has the issues pointed out by the (now removed) FIXME, but also has
an issue on macOS where years before 1900 are not supported.
As noted in the prototype comments, this implementation becomes less
accurate as the precision approaches the limit of 100. For example:
(3).toPrecision(100)
Should result in "3." followed by 99 "0"s. However, due to the loss of
accuracy in the floating point computations, we currently result in
"2.9999999...".
This is another major milestone on our journey towards removing global
VM exception state :^)
Does pretty much exactly what it says on the tin: updating
ASTNode::execute() to return a Completion instead of a plain value. This
will *also* allow us to eventually remove the non-standard unwinding
mechanism and purely rely on the various completion types.
In the end this is a nicer API than having separate has_{value,target}()
and having to check those first, and then making another Optional from
the unwrapped value:
completion.has_value() ? completion.value() : Optional<Value> {}
// ^^^^^^^^^^^^^^^^^^
// Implicit creation of non-empty Optional<Value>
This way we need to unwrap the optional ourselves, but can easily pass
it to something else as well.
This is in anticipation of the AST using completions :^)
It also needs to be able to take what the spec calls 'empty', which is
an Optional<Value> in this case (*not* an empty JS::Value). The common
use case is updating a completion with another completion, that may also
have an empty [[Value]] slot.
This is a normative change in the Intl spec:
f0f66cf
There are two main changes here:
1. Converting BigInt/Number objects to mathematical values.
2. A change in how ToRawPrecision computes its exponent and significant
digits.
For (1), we do not yet support BigInt number formatting, thus already
have coerced Number objects to a double. When BigInt is supported, the
number passed into these methods will likely still be a Value, thus can
be coereced then.
For (2), our implementation already returns the expected edge-case
results pointed out on the spec PR.
This is a normative change in the Intl spec:
f0f66cf
Our implementation is unaffected by this change. LibUnicode pre-computes
positive, negative, and signless format patterns, so we already format
negative infinity correctly. Also, the CLDR does not contain specific
locale-dependent strings for negative infinity anyways.
This matches the text of the spec, and is more correct since the
variable is being updated, not defined it.
See: 5ab1822
---
I also changed `test_year += 1` to `test_year++` for consistency with
step 11.c that has the same description.
The spec has a note stating that resolve binding will always return a
reference whose [[ReferencedName]] field is name. However this is not
correct as the underlying method GetIdentifierReference may throw on
env.HasBinding(name) thus it can throw. However, there are some
scenarios where it cannot throw because the reference is known to exist
in that case we use MUST with a comment.
The this value is only supposed to be set via the BindThisValue and
accessed via the GetThisBinding AOs, so exposing a direct getter/setter
would only lead to potentially non-spec-compliant behavior down the
line.
...for now - the reason being that the AST breaks 'completion bubbling'
and returns a plain Value, and code at the call site relies on the VM
having an exception set when converting the plain value back into a
completion.
Fixes#11301.
