Before this we used an ad-hoc combination of references and 'variables'
stored in a hashmap. This worked in most cases but is not spec like.
Additionally hoisting, dynamically naming functions and scope analysis
was not done properly.
This patch fixes all of that by:
- Implement BindingInitialization for destructuring assignment.
- Implementing a new ScopePusher which tracks the lexical and var
scoped declarations. This hoists functions to the top level if no
lexical declaration name overlaps. Furthermore we do checking of
redeclarations in the ScopePusher now requiring less checks all over
the place.
- Add methods for parsing the directives and statement lists instead
of having that code duplicated in multiple places. This allows
declarations to pushed to the appropriate scope more easily.
- Remove the non spec way of storing 'variables' in
DeclarativeEnvironment and make Reference follow the spec instead of
checking both the bindings and 'variables'.
- Remove all scoping related things from the Interpreter. And instead
use environments as specified by the spec. This also includes fixing
that NativeFunctions did not produce a valid FunctionEnvironment
which could cause issues with callbacks and eval. All
FunctionObjects now have a valid NewFunctionEnvironment
implementation.
- Remove execute_statements from Interpreter and instead use
ASTNode::execute everywhere this simplifies AST.cpp as you no longer
need to worry about which method to call.
- Make ScopeNodes setup their own environment. This uses four
different methods specified by the spec
{Block, Function, Eval, Global}DeclarationInstantiation with the
annexB extensions.
- Implement and use NamedEvaluation where specified.
Additionally there are fixes to things exposed by these changes to eval,
{for, for-in, for-of} loops and assignment.
Finally it also fixes some tests in test-js which where passing before
but not now that we have correct behavior :^).
We need both a GlobalObject and Realm now, but can get the former from
the latter (once initialized).
This also fixes JS execution in LibWeb, as we failed to set the Realm of
the newly created Interpreter in this function.
To better follow the spec, we need to distinguish between the current
execution context's lexical environment and variable environment.
This patch moves us to having two record pointers, although both of
them point at the same environment records for now.
This patch adds FunctionEnvironmentRecord as a subclass of the existing
DeclarativeEnvironmentRecord. Things that are specific to function
environment records move into there, simplifying the base.
Most of the abstract operations related to function environment records
are rewritten to match the spec exactly. I also had to implement
GetThisEnvironment() and GetSuperConstructor() to keep tests working
after the changes, so that's nice as well. :^)
This patch makes the following name changes:
- ScopeObject => EnvironmentRecord
- LexicalEnvironment => DeclarativeEnvironmentRecord
- WithScope => ObjectEnvironmentRecord
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
With one small exception, this is how we've been using this API already,
and it makes sense: a Program is just a ScopeNode with any number of
statements, which are executed one by one. There's no explicit return
value at the end, only a completion value of the last value-producing
statement, which we then access using VM::last_value() if needed (e.g.
in the REPL).
