protected override PExpr DoVisit()
{
if (_nativeEnum == null)
{
if (IsPendingOrSignal(ref _generator, Expr.Generator))
{
return(PendingOrSignal(_generator));
}
var a = _generator.Result.ToNative(Global) as IEnumerable;
if (a == null)
{
return(new PExpr(new RuntimeError(Expr.Generator, "foreach generator is not an IEnumerable.")));
}
try
{
_nativeEnum = a.GetEnumerator();
}
catch (Exception ex)
{
return(new PExpr(new RuntimeError(Expr.Generator, ex.Message)));
}
}
for ( ; ;)
{
if (_currentVariable == null)
{
bool hasNext;
try
{
hasNext = _nativeEnum.MoveNext();
}
catch (Exception ex)
{
return(new PExpr(new RuntimeError(Expr.Generator, ex.Message)));
}
if (!hasNext)
{
break;
}
_currentVariable = Visitor.ScopeManager.Register(Expr.Variable, _index++);
_currentVariable.SetValue(Expr.Variable, Global.Create(_nativeEnum.Current));
}
if (IsPendingOrSignal(ref _code, Expr.Code))
{
return(PendingOrSignal(_code));
}
_code = new PExpr();
Visitor.ScopeManager.Unregister(Expr.Variable);
_currentVariable = null;
}
_nativeEnum = null;
return(SetResult(RuntimeObj.Undefined));
}
protected override PExpr DoVisit()
{
if (IsPendingOrSignal(ref _operand, Expr.Operand))
{
return(PendingOrSignal(_operand));
}
RefRuntimeObj r = _operand.Result as RefRuntimeObj;
if (r == null)
{
return(SetResult(new RuntimeError(Expr.Operand, "Invalid increment or decrement operand.")));
}
var newValue = DoubleObj.Create(_operand.Result.ToDouble() + (Expr.Plus ? 1.0 : -1.0));
if (Expr.Prefix)
{
return(SetResult(r.SetValue(Expr, newValue)));
}
var result = SetResult(r.Value);
r.SetValue(Expr, newValue);
return(result);
}
protected override PExpr DoVisit()
{
if (IsPendingOrSignal(ref _right, Expr.Right))
{
return(PendingOrSignal(_right));
}
if (IsPendingOrSignal(ref _left, Expr.Left))
{
return(PendingOrSignal(_left));
}
RefRuntimeObj r = _left.Result as RefRuntimeObj;
if (r == null)
{
return(SetResult(new RuntimeError(Expr.Left, "Invalid assignment left-hand side.")));
}
return(SetResult(r.SetValue(Expr, _right.Result)));
}