protected override void Initialize(EvaluationContext context)
{
_lhsKind = LhsKind.Assignment;
var engine = context.Engine;
if (_leftNode is VariableDeclaration variableDeclaration)
{
_lhsKind = variableDeclaration.Kind == VariableDeclarationKind.Var
? LhsKind.VarBinding
: LhsKind.LexicalBinding;
var variableDeclarationDeclaration = variableDeclaration.Declarations[0];
var id = variableDeclarationDeclaration.Id;
if (_lhsKind == LhsKind.LexicalBinding)
{
_tdzNames = new List <string>(1);
id.GetBoundNames(_tdzNames);
}
if (id is BindingPattern bindingPattern)
{
_destructuring = true;
_assignmentPattern = bindingPattern;
}
else
{
var identifier = (Identifier)id;
_expr = new JintIdentifierExpression(identifier);
}
}
else if (_leftNode is BindingPattern bindingPattern)
{
_destructuring = true;
_assignmentPattern = bindingPattern;
}
else if (_leftNode is MemberExpression memberExpression)
{
_expr = new JintMemberExpression(memberExpression);
}
else
{
_expr = new JintIdentifierExpression((Identifier)_leftNode);
}
_body = Build(_forBody);
_right = JintExpression.Build(engine, _rightExpression);
}
/// <summary>
/// https://tc39.es/ecma262/#sec-runtime-semantics-forin-div-ofbodyevaluation-lhs-stmt-iterator-lhskind-labelset
/// </summary>
private Completion BodyEvaluation(
JintExpression lhs,
JintStatement stmt,
IIterator iteratorRecord,
IterationKind iterationKind,
LhsKind lhsKind,
IteratorKind iteratorKind = IteratorKind.Sync)
{
var oldEnv = _engine.ExecutionContext.LexicalEnvironment;
var v = Undefined.Instance;
var destructuring = _destructuring;
string lhsName = null;
var completionType = CompletionType.Normal;
var close = false;
try
{
while (true)
{
LexicalEnvironment iterationEnv = null;
if (!iteratorRecord.TryIteratorStep(out var nextResult))
{
close = true;
return(new Completion(CompletionType.Normal, v, null, Location));
}
if (iteratorKind == IteratorKind.Async)
{
// nextResult = await nextResult;
}
var nextValue = nextResult.Get(CommonProperties.Value);
close = true;
Reference lhsRef = null;
if (lhsKind != LhsKind.LexicalBinding)
{
if (!destructuring)
{
lhsRef = (Reference)lhs.Evaluate();
}
}
else
{
iterationEnv = LexicalEnvironment.NewDeclarativeEnvironment(_engine, oldEnv);
if (_tdzNames != null)
{
BindingInstantiation(iterationEnv);
}
_engine.UpdateLexicalEnvironment(iterationEnv);
if (!destructuring)
{
if (lhsName == null)
{
lhsName = ((Identifier)((VariableDeclaration)_leftNode).Declarations[0].Id).Name;
}
lhsRef = _engine.ResolveBinding(lhsName);
}
}
if (!destructuring)
{
// If lhsRef is an abrupt completion, then
// Let status be lhsRef.
if (lhsKind == LhsKind.LexicalBinding)
{
lhsRef.InitializeReferencedBinding(nextValue);
}
else
{
_engine.PutValue(lhsRef, nextValue);
}
}
else
{
BindingPatternAssignmentExpression.ProcessPatterns(
_engine,
_assignmentPattern,
nextValue,
iterationEnv,
checkObjectPatternPropertyReference: _lhsKind != LhsKind.VarBinding);
if (lhsKind == LhsKind.Assignment)
{
// DestructuringAssignmentEvaluation of assignmentPattern using nextValue as the argument.
}
else if (lhsKind == LhsKind.VarBinding)
{
// BindingInitialization for lhs passing nextValue and undefined as the arguments.
}
else
{
// BindingInitialization for lhs passing nextValue and iterationEnv as arguments
}
}
var result = stmt.Execute();
_engine.UpdateLexicalEnvironment(oldEnv);
if (!ReferenceEquals(result.Value, null))
{
v = result.Value;
}
if (result.Type == CompletionType.Break && (result.Identifier == null || result.Identifier == _statement?.LabelSet?.Name))
{
return(new Completion(CompletionType.Normal, v, null, Location));
}
if (result.Type != CompletionType.Continue || (result.Identifier != null && result.Identifier != _statement?.LabelSet?.Name))
{
if (result.Type != CompletionType.Normal)
{
return(result);
}
}
}
}
catch
{
completionType = CompletionType.Throw;
throw;
}
finally
{
if (close)
{
iteratorRecord.Close(completionType);
}
_engine.UpdateLexicalEnvironment(oldEnv);
}
}
/// <summary>
/// https://tc39.es/ecma262/#sec-runtime-semantics-forin-div-ofbodyevaluation-lhs-stmt-iterator-lhskind-labelset
/// </summary>
private Completion BodyEvaluation(
EvaluationContext context,
JintExpression lhs,
JintStatement stmt,
IteratorInstance iteratorRecord,
IterationKind iterationKind,
LhsKind lhsKind,
IteratorKind iteratorKind = IteratorKind.Sync)
{
var engine = context.Engine;
var oldEnv = engine.ExecutionContext.LexicalEnvironment;
var v = Undefined.Instance;
var destructuring = _destructuring;
string lhsName = null;
var completionType = CompletionType.Normal;
var close = false;
try
{
while (true)
{
EnvironmentRecord iterationEnv = null;
if (!iteratorRecord.TryIteratorStep(out var nextResult))
{
close = true;
return(new Completion(CompletionType.Normal, v, null, Location));
}
if (iteratorKind == IteratorKind.Async)
{
// nextResult = await nextResult;
ExceptionHelper.ThrowNotImplementedException("await");
}
var nextValue = nextResult.Get(CommonProperties.Value);
close = true;
var lhsRef = new ExpressionResult();
if (lhsKind != LhsKind.LexicalBinding)
{
if (!destructuring)
{
lhsRef = lhs.Evaluate(context);
}
}
else
{
iterationEnv = JintEnvironment.NewDeclarativeEnvironment(engine, oldEnv);
if (_tdzNames != null)
{
BindingInstantiation(iterationEnv);
}
engine.UpdateLexicalEnvironment(iterationEnv);
if (!destructuring)
{
var identifier = (Identifier)((VariableDeclaration)_leftNode).Declarations[0].Id;
lhsName ??= identifier.Name;
lhsRef = new ExpressionResult(ExpressionCompletionType.Normal, engine.ResolveBinding(lhsName), identifier.Location);
}
}
if (context.DebugMode)
{
context.Engine.DebugHandler.OnStep(_leftNode);
}
var status = new Completion();
if (!destructuring)
{
if (lhsRef.IsAbrupt())
{
close = true;
status = new Completion(lhsRef);
}
else if (lhsKind == LhsKind.LexicalBinding)
{
((Reference)lhsRef.Value).InitializeReferencedBinding(nextValue);
}
else
{
engine.PutValue((Reference)lhsRef.Value, nextValue);
}
}
else
{
status = BindingPatternAssignmentExpression.ProcessPatterns(
context,
_assignmentPattern,
nextValue,
iterationEnv,
checkObjectPatternPropertyReference: _lhsKind != LhsKind.VarBinding);
if (lhsKind == LhsKind.Assignment)
{
// DestructuringAssignmentEvaluation of assignmentPattern using nextValue as the argument.
}
else if (lhsKind == LhsKind.VarBinding)
{
// BindingInitialization for lhs passing nextValue and undefined as the arguments.
}
else
{
// BindingInitialization for lhs passing nextValue and iterationEnv as arguments
}
}
if (status.IsAbrupt())
{
engine.UpdateLexicalEnvironment(oldEnv);
if (_iterationKind == IterationKind.AsyncIterate)
{
iteratorRecord.Close(status.Type);
return(status);
}
if (iterationKind == IterationKind.Enumerate)
{
return(status);
}
iteratorRecord.Close(status.Type);
return(status);
}
var result = stmt.Execute(context);
engine.UpdateLexicalEnvironment(oldEnv);
if (!ReferenceEquals(result.Value, null))
{
v = result.Value;
}
if (result.Type == CompletionType.Break && (result.Target == null || result.Target == _statement?.LabelSet?.Name))
{
completionType = CompletionType.Normal;
return(new Completion(CompletionType.Normal, v, null, Location));
}
if (result.Type != CompletionType.Continue || (result.Target != null && result.Target != _statement?.LabelSet?.Name))
{
completionType = result.Type;
if (result.IsAbrupt())
{
close = true;
return(result);
}
}
}
}
catch
{
completionType = CompletionType.Throw;
throw;
}
finally
{
if (close)
{
try
{
iteratorRecord.Close(completionType);
}
catch
{
// if we already have and exception, use it
if (completionType != CompletionType.Throw)
{
throw;
}
}
}
engine.UpdateLexicalEnvironment(oldEnv);
}
}
