private void ExecuteReduceAction(ActionRecord action)
{
ParserState oldState = _currentState;
int popCnt = action.PopCount;
//Get new node's child nodes - these are nodes being popped from the stack
AstNodeList childNodes = new AstNodeList();
for (int i = 0; i < action.PopCount; i++)
{
AstNode child = Stack[Stack.Count - popCnt + i].Node;
if (child.Term.IsSet(TermOptions.IsPunctuation))
{
continue;
}
//Transient nodes - don't add them but add their childrent directly to grandparent
if (child.Term.IsSet(TermOptions.IsTransient))
{
foreach (AstNode grandChild in child.ChildNodes)
{
childNodes.Add(grandChild);
}
continue;
}
//Add normal child
childNodes.Add(child);
}
//recover state, location and pop the stack
SourceSpan newNodeSpan;
if (popCnt == 0)
{
newNodeSpan = new SourceSpan(_currentToken.Location, 0);
}
else
{
SourceLocation firstPopLoc = Stack[Stack.Count - popCnt].Node.Location;
int lastPopEndPos = Stack[Stack.Count - 1].Node.Span.EndPos;
newNodeSpan = new SourceSpan(firstPopLoc, lastPopEndPos - firstPopLoc.Position);
_currentState = Stack[Stack.Count - popCnt].State;
Stack.Pop(popCnt);
}
//Create new node
AstNode node = CreateNode(action, newNodeSpan, childNodes);
action.NonTerminal.OnNodeCreated(node);
// Push node/current state into the stack
Stack.Push(node, _currentState);
//switch to new state
ActionRecord gotoAction;
if (_currentState.Actions.TryGetValue(action.NonTerminal.Key, out gotoAction))
{
_currentState = gotoAction.NewState;
}
else
{
//should never happen
throw new CompilerException(string.Format("Cannot find transition for input {0}; state: {1}, popped state: {2}",
action.NonTerminal, oldState, _currentState));
}
}//method
public ParserActionEventArgs(ParserState state, Token input, ActionRecord action)
{
State = state;
Input = input;
Action = action;
}
private void ExecuteShiftAction(ActionRecord action)
{
Stack.Push(_currentToken, _currentState);
_currentState = action.NewState;
NextToken();
}