public ParserStateException(StatementState state, LexedToken curTok, AllowedTransition transitionRecord) :
base($"Invalid token {curTok.TokenType.ToString()} in {state.ToString()}")
{
this.state = state;
this.curTok = curTok;
this.transitionRecord = transitionRecord;
}
/// <summary>
/// Moves to the next token , additionally ensures that the token transition is valid
/// generally looks at the global token tree , but subclasses can provide thier own allowed transitions to provide dynamic , localized validation
/// </summary>
/// <param name="tr"></param>
/// <returns></returns>
public LexedToken?MoveNext(AllowedTransition tr, bool SkipWhitespace)
{
if (CurrentIndex + 1 == Tokens.Count)
{
return(null);
}
CurrentIndex++;
var curTok = Tokens[CurrentIndex];
if (SkipWhitespace)
{
while (curTok.TokenType == LexedTokenType.WHITESPACE)
{
if (CurrentIndex + 1 == Tokens.Count)
{
return(null);
}
CurrentIndex++;
curTok = Tokens[CurrentIndex];
}
}
var TransitionRecord = tr;
if (tr == null)
{
TransitionRecord = ParseStates.StateTransitions[State];
}
if (!TransitionRecord.ContainsKey(curTok.TokenType))
{
throw new ParserStateException(State, curTok, TransitionRecord);
}
CurrentTransition = TransitionRecord;
return(curTok);
}
