/// <summary>
/// http://www.ecma-international.org/ecma-262/5.1/#sec-12.14
/// </summary>
/// <param name="tryStatement"></param>
/// <returns></returns>
public Completion ExecuteTryStatement(TryStatement tryStatement)
{
var b = ExecuteStatement(tryStatement.Block);
if (b.Type == Completion.Throw)
{
// execute catch
if (tryStatement.Handlers.Any())
{
foreach (var catchClause in tryStatement.Handlers)
{
var c = _engine.GetValue(b);
var oldEnv = _engine.ExecutionContext.LexicalEnvironment;
var catchEnv = LexicalEnvironment.NewDeclarativeEnvironment(_engine, oldEnv);
catchEnv.Record.CreateMutableBinding(catchClause.Param.Name);
catchEnv.Record.SetMutableBinding(catchClause.Param.Name, c, false);
_engine.ExecutionContext.LexicalEnvironment = catchEnv;
b = ExecuteStatement(catchClause.Body);
_engine.ExecutionContext.LexicalEnvironment = oldEnv;
}
}
}
if (tryStatement.Finalizer != null)
{
var f = ExecuteStatement(tryStatement.Finalizer);
if (f.Type == Completion.Normal)
{
return b;
}
return f;
}
return b;
}
private void EmitTryStatement(TryStatement s)
{
Write("try");
Emit(s.Block);
foreach (var handler in s.Handlers)
{
Write("catch(");
Emit(handler.Param);
Write(") ");
Emit(handler.Body);
}
if(null != s.Finalizer)
{
Write("finally");
Emit(s.Finalizer);
}
}
