public PhpReference PeekReferenceUnchecked(int i)
{
object item = Items[Top - i];
PhpReference result;
PhpRuntimeChain php_chain;
// the caller may not pushed a reference although the formal argument is a reference:
// it doesn't matter if called by callback:
if ((result = item as PhpReference) == null)
{
// caller may have pushed a runtime chain => evaluate it:
if ((php_chain = item as PhpRuntimeChain) != null)
{
// call state has to be stored since chain can call arbitrary user code:
CallState call_state = SaveCallState();
result = php_chain.GetReference(Context);
RestoreCallState(call_state);
}
else
{
// the reason of copy is not exactly known (it may be returning by copy as well as passing by copy):
result = new PhpReference(PhpVariable.Copy(item, CopyReason.Unknown));
// Reports an error in the case that we are not called by callback.
// Although, this error is fatal one can switch throwing exceptions off.
// If this is the case the afterwards behavior will be the same as if callback was called.
if (!Callback)
{
// warning (can invoke user code => we have to save and restore callstate):
CallState call_state = SaveCallState();
PhpException.ArgumentNotPassedByRef(i, CalleeName);
RestoreCallState(call_state);
}
}
}
return(result);
}