/// <summary>
/// Operates on a Token stream using the ParsingTable
/// </summary>
/// <param name="tokens"></param>
/// <param name="generateScript"></param>
/// <returns></returns>
public static IEnumerator <object> Execute <T>(string inputString) where T : IOrbLanguage
{
Debug.Log("Execute");
//Create an instance of the language we are going to work with.
IOrbLanguage language = (IOrbLanguage)System.Activator.CreateInstance(typeof(T));
//Create a place to store out input tokens (nullable so null = EOF when processing)
List <ProcessedToken?> inputTokens = null;
//Call scan, to get our list of beginning tokens.
yield return(OrbLexer.Scan(language, inputString, (object d) => { inputTokens = (List <ProcessedToken?>)d; }));
Debug.Log("Scanning Finished");
OrbUtils.PrintList <ProcessedToken?>(inputTokens);
List <object> TERMINALS = language.GetTERMINALS();
List <object> nonTerminals = language.GetNonTerminals();
ParserInstruction[][] ParseTable = language.GetParseTable();
//The parsing stack
List <ParseStackElement> parsingStack = new List <ParseStackElement>();
//Place state 0 onto the stack
parsingStack.Add(new ParseStackElement(ParseStackElement.Type.State, 0));
//The current location in the parse
int currencyIndicator = 0;
//Begin the Looop!
while (true)
{
yield return(null);
Debug.Log(OrbUtils.PrintList(parsingStack, false) + "|\\|/| -> " + inputTokens[currencyIndicator]);
ParseStackElement top = parsingStack[parsingStack.Count - 1];
//Look at top of stack, if it is a Token, then we need to do a GoTo,
if (top.type == ParseStackElement.Type.Token)
{
//Debug.Log("GoTo");
//DO A GOTO
ParseStackElement previousState = parsingStack[parsingStack.Count - 2];
//Debug.Log(previousState);
if (previousState.type != ParseStackElement.Type.State)
{
Debug.LogError("Stack parsing has broken due to invalid GoTo");
yield break;
}
//Calculate the column for the Token that is on top of the stack.
int tokenColumn = TERMINALS.Count + top.scannedToken.tokenSymbolLocation;
//Push onto the stack the state we are supposed to GoTo.
parsingStack.Add(new ParseStackElement(ParseStackElement.Type.State, (int)ParseTable[previousState.parserStateIndex][tokenColumn].value));
}
else
{
//Otherwise we look at the current state and the currency indiciator
//Get the input token we are looking at
ProcessedToken currentInputToken = (ProcessedToken)inputTokens[currencyIndicator];
//It can (should) only be a non terminal, so calculate its column on the parse table.
int tokenColumn = currentInputToken.tokenSymbolLocation;
Debug.Log(currentInputToken.data);
Debug.Log(tokenColumn + "/" + (nonTerminals.Count + TERMINALS.Count));
ParserInstruction targetInstruction = ParseTable[top.parserStateIndex][tokenColumn];
if (targetInstruction.instruction == ParserInstruction.Instruction.ACCEPT)
{
ProcessedToken finalToken = (ProcessedToken)parsingStack[parsingStack.Count - 2].scannedToken;
//Execute the final rule.
language.StartLangCoroutine(finalToken.rule, new CoroutineWrapper(language, finalToken, (object data) => { }));
break;
}
else if (targetInstruction.instruction == ParserInstruction.Instruction.SHIFT)
{
Debug.Log("Shift");
//If it is a shift, we put this token on the stack,
parsingStack.Add(new ParseStackElement(ParseStackElement.Type.Token, 0, currentInputToken));
//advance the currency token,
currencyIndicator++;
//then the new state on the stack.
parsingStack.Add(new ParseStackElement(ParseStackElement.Type.State, (int)targetInstruction.value));
}
else if (targetInstruction.instruction == ParserInstruction.Instruction.REDUCE)
{
//If it is reduce, we... reduce
ProductionRule productionRule = language.GetProductionRules()[targetInstruction.value];
int removalCount = productionRule.rhsSize * 2;
//We pop off twice as many tokens as the rhs of the reduce instruction.
List <ParseStackElement> poppedList = parsingStack.GetRange(parsingStack.Count - removalCount, removalCount);
parsingStack.RemoveRange(parsingStack.Count - removalCount, removalCount);
//Create a list of all of the ScannedTokens
List <ProcessedToken> scannedTokensList = new List <ProcessedToken>();
for (int i = 0; i < poppedList.Count; i++)
{
if (poppedList[i].type == ParseStackElement.Type.Token)
{
scannedTokensList.Add(poppedList[i].scannedToken);
}
}
//Call the appropriate operation (Performi the Reduction)
ProcessedToken resultingToken = new ProcessedToken(productionRule.result, productionRule.coroutineName, scannedTokensList);
//Put the resulting LHS token onto the stack.
parsingStack.Add(new ParseStackElement(ParseStackElement.Type.Token, 0, resultingToken));
}
else
{
OrbUtils.PrintList(parsingStack);
Debug.Log(currentInputToken);
inputTokens.RemoveRange(0, currencyIndicator);
//PrintList(inputTokens);
Debug.LogError("Stack parsing has broken due to invalid Instruction: " + System.Enum.GetName(typeof(ParserInstruction.Instruction), targetInstruction.instruction));
yield break;
}
}
}
Debug.Log("EndExecute");
}
/// <summary>
/// Scans a string into a token stream
/// </summary>
/// <param name="input"></param>
/// <returns></returns>
public static IEnumerator <object> Scan(IOrbLanguage enviroment, string input, Callback callback)
{
List <ProcessedToken?> tokens = new List <ProcessedToken?>();
List <object> TERMINALS = enviroment.GetTERMINALS();
SymbolStringTuple[] tuples = enviroment.GetRegexPairs();
string remainder = input;
string text = "";
string testingText = "";
Regex regex;
while (remainder.Length > 0)
{
//Debug.Log("Top of While");
ProcessedToken?token = null;
int i = 0;
for (; i < TERMINALS.Count; i++)
{
//Debug.Log("For1: " + tuples[i].str);
text = "";
testingText = ""; // Track the current testing string.
regex = new Regex(tuples[i].str);
//Debug.Log(regex);
for (int k = 0; k < remainder.Length; k++)
{
//Debug.Log("For2: " + remainder.Length + " | " + k);
testingText += remainder[k];
if (regex.IsMatch(testingText))
{
text = testingText; // Store our string since we know that this is the valid string.
//Debug.Log("Is Match: " + regex + " => " + testingText);
//Create the processedtoken
token = new ProcessedToken(i, null, text);
//Execute the code for reading this token.
yield return(enviroment.StartLangCoroutine(tuples[i].coroutineName, new CoroutineWrapper(enviroment, (ProcessedToken)token, (object d) => { })));
}
}
if (token != null)
{
//Debug.Log("Breaking.");
break;
}
}
if (token != null)
{
if (tuples[i].ignorable)
{
//We have ignored this section
}
else
{
//Debug.Log(text + " | " + token);
tokens.Add(token);
}
//Debug.Log("Pre<"+remainder+">");
remainder = remainder.Substring(text.Length);
//Debug.Log("Post<" + remainder + ">");
text = "";
}
else
{
//Log ERROR
Debug.LogError("Syntax Read Error: '" + testingText + "'");
}
//pause before continuing
yield return(null);
}
tokens.Add(null);
callback(tokens);
}
