private NextStateRec(Type ofType, string name, TokenRef token, string identifier, ParseResponse response)
{
Name = name;
Identifier = identifier;
OfType = ofType;
Token = token;
Sequence = null; // end of list by default
Alternate = null; // no alternate by default
Response = response;
}
public static NextStateRec CreateTokenRef(string name, TokenRef.Type type, ParseResponse response)
{
NextStateRec nsRec;
switch (type)
{
case TokenRef.Type.Null:
throw new FormatException($"SourceObject Type {type.ToString()} is valid BUT NOT in the context as a Next State Token Ref!");
case TokenRef.Type.Empty:
nsRec = new NextStateRec(Type.TokenRef, TokenRef.CreateEmpty(), null, response);
break;
case TokenRef.Type.Identifier:
if (!(name is null))
{
throw new ArgumentNullException(nameof(name), $"NextStateRecords can not contain Identifier Tokens with predefined names -{nameof(name)} must be set to 'null', not '{name}'!");
}
nsRec = new NextStateRec(Type.TokenRef, TokenRef.CreateIdentifier(), response);
break;
case TokenRef.Type.Keyword:
nsRec = new NextStateRec(Type.TokenRef, TokenRef.CreateKeyword(name), name, response);
break;
case TokenRef.Type.Operator:
nsRec = new NextStateRec(Type.TokenRef, TokenRef.CreateOperator(name), name, response);
break;
case TokenRef.Type.Error:
throw new NotImplementedException("Error types yet to be implemented!");
default:
throw InvalidEnumValueException.InvalidArgument(typeof(TokenRef.Type), type, nameof(name));
}
return(nsRec);
}
public static NextStateRec CreateGrammaRef(string name)
{
return(new NextStateRec(Type.GrammaRef, name, TokenRef.CreateNonToken(), ParseResponse.Next));
}
public static NextStateRec CreateEmpty(ParseResponse response)
{
return(new NextStateRec(Type.TokenRef, "Empty", TokenRef.CreateEmpty(), "&Empty", response));
}
public ParseResponse GoToNextState(SourceObject next)
{
ParseResponse response = ParseResponse.Null;
NextStateRec state = CurrentState;
TokenRef token = TokenRef.Create(next.OfType, next.Text);
do
{
Debug.WriteIf(state != null, $"{{{token}}} against {{{state.Token}}}", "Check");
if (state == null)
{
response = ParseResponse.Reject;
Debug.WriteLine(" -Match! Response = Reject");
}
else if (token == state.Token)
{
response = state.Response;
Debug.WriteLine(" -Match! Response = " + response);
}
else if (state.Token.OfType == TokenRef.Type.Empty)
{
response = state.Response;
Debug.WriteLine(" -Match on Empty! Response = " + response);
}
else if (state.Token.OfType == TokenRef.Type.Null)
{
if (state.Response == ParseResponse.Next)
{
state = state.Sequence;
response = ParseResponse.Null;
}
else
{
response = state.Response;
}
Debug.WriteLine(" -Special Response = " + response);
}
else
{
Debug.WriteLine(" -NO Match! Check Next");
state = state.Sequence;
}
} while (response == ParseResponse.Null);
// Determine next state based on response
Debug.Write($"{{{state.Token }}} -> ", "Result");
switch (response)
{
case ParseResponse.Next:
CurrentState = state.Sequence;
break;
default:
throw new InvalidEnumValueException(typeof(ParseResponse), response);
}
Debug.WriteLine($"{{{CurrentState.Token}}} -Response {response}!");
return(response);
}
