/// <summary>
/// Feeds all tokens to the parser and returns the last result.
/// </summary>
private RuleResult FeedAll(IRuleParser parser, IEnumerable <Token> tokens)
{
RuleResult lastResult = default;
foreach (Token t in tokens)
{
lastResult = parser.FeedToken(t);
}
return(lastResult);
}
public RuleResult FeedToken(Token t)
{
if (_isFinished)
{
throw new Exception("Tried to feed a token to an already-finished ThenChainParser.");
}
var currentCallabck = _ruleSequence[_currentRuleIndex].onMatched;
// HACK: Create the first rule, if it hasn't been already.
if (_currentRule == null)
{
_currentRule = _ruleSequence[_currentRuleIndex].ruleFactory();
}
// Feed the token to the current rule
var result = _currentRule.FeedToken(t);
// If it failed, cascade that failure upwards
if (result.status == RuleStatus.Failed)
{
return(result);
}
// If it succeeded, invoke the callback and move to the next rule
if (result.status == RuleStatus.Complete)
{
currentCallabck(result.node);
_currentRuleIndex++;
// If the last rule just succeeded, the whole chain is complete.
if (_currentRuleIndex >= _ruleSequence.Count)
{
_isFinished = true;
return(RuleResult.Complete(_node));
}
_currentRule = _ruleSequence[_currentRuleIndex].ruleFactory();
}
return(RuleResult.GoodSoFar());
}