public SyntaxTree Parse(TokenList tokenList)
{
LRParsingMap parsingMap = GetParsingMap();
RegulationList grammar = GetGrammar();
//TODO:这个convertor以后是可以配置的。
var tokenTypeConvertor = new TokenType2TreeNodeType();
var context = new ParsingContext(tokenList, grammar, parsingMap, tokenTypeConvertor);
while (context.CurrentTokenIndex < context.TokenList.Count + 1)
{
PrintParsingProgress(context);
TreeNodeType nodeType = context.CurrentNodeType();
int stateId = context.StateIdStack.Peek();
LRParsingAction action = parsingMap.GetAction(stateId, nodeType);
int currentTokenIndex = action.Execute(context);
context.CurrentTokenIndex = currentTokenIndex;
}
PrintLastState(context);
if (context.TreeStack.Count > 0)
{
return(context.TreeStack.Peek());
}
else
{
return(new SyntaxTree());
}
}
public override int Execute(ParsingContext context)
{
Regulation regulation = context.Grammar[RegulationId - 1];
var newNode = new SyntaxTree();
int tokenCount = 0;
int count = regulation.RightPart.Count();
for (int i = 0; i < count; i++)
{
var item = context.TreeStack.Pop();
context.StateIdStack.Pop();//只弹出，不再使用。
newNode.Children.Insert(0, item);
item.Parent = newNode;
tokenCount += item.MappedTokenLength;
if (i == 0)
{
newNode.MappedTokenStartIndex = item.MappedTokenStartIndex;
}
}
newNode.MappedTokenLength = tokenCount;
newNode.MappedTotalTokenList = context.TokenList;
newNode.NodeType = regulation.Left;
context.TreeStack.Push(newNode);
int stateId = context.StateIdStack.Peek();
LRParsingAction gotoAction = context.ParsingMap.GetAction(stateId, regulation.Left);
gotoAction.Execute(context);
return(context.CurrentTokenIndex);
}