thompsonvm2

static Token[] thompsonVM (Instruction[] program, String input) {
        int inputLength, beginIndex;
        char currentCharacter;
        ArrayList<Integer> currentList, nextList;
        ArrayList<Token> returnTokens;
        Token matchedToken;
        String currentMatchedString = "";

        beginIndex = 0;                         //used to save the current match as a substring of the input
        inputLength = input.length();           //stored for slightly quicker runtime
        currentList = new ArrayList<>();        //current list of threads as integers (line number in the program)
        nextList = new ArrayList<>();           //next list of threads
        returnTokens = new ArrayList<>();      //list of matched strings in the form ID:'value'
        matchedToken = new Token("", "");       //the current matched token

        currentList.add(0);                     //start the program with a single thread at instruction 0

        for (int characterIndex = 0; characterIndex <= inputLength; characterIndex++) {
            if (characterIndex != inputLength) {
                currentCharacter = input.charAt(characterIndex);
            } else {
                currentCharacter = 0;           //if past the last character, set to null
            }
            for (int currentInstruction, instructionIndex = 0; instructionIndex < currentList.size(); instructionIndex++) {  //for all instructions in currentList
                currentInstruction = currentList.get(instructionIndex);
                switch (program[currentInstruction].opCode) {
                    case CHAR:
                        CharInstruction charInst = (CharInstruction)program[currentInstruction];
                        if (!(currentCharacter >= charInst.lowerLimit && currentCharacter <= charInst.upperLimit)) {
                        } else {
                            nextList.add(currentInstruction + 1);
                            System.out.println("Matched char " + currentCharacter);
                        }
            break;
                    case MATCH:
                        MatchInstruction matchInst = (MatchInstruction)program[currentInstruction];
                        currentMatchedString = (input.substring(beginIndex, characterIndex));
                        if (currentMatchedString.length() > matchedToken.getValue().length()) {
                            matchedToken.setID(matchInst.tokenID);
                            matchedToken.setValue(currentMatchedString);
                        }
                        System.out.println("Matched word " + currentMatchedString);
                        continue;
                    case JMP:
                        JmpInstruction jmpInst = (JmpInstruction)program[currentInstruction];
                        currentList.add(jmpInst.jumpTo);
                        break;
                    case SPLIT:
                        SplitInstruction splitInst = (SplitInstruction)program[currentInstruction];
                        currentList.add(splitInst.firstJump);
                        currentList.add(splitInst.secondJump);
                        break;
                }
            }

            currentList.clear();
            currentList.addAll(nextList);
            nextList.clear();

            if (currentList.isEmpty() && !matchedToken.getValue().isEmpty()) {                //if all threads died
                currentList.add(0);
                returnTokens.add(matchedToken);
                matchedToken = new Token("", "");
                beginIndex = characterIndex + 1;
            }
        }
        Token[] returnArray = new Token[returnTokens.size()];
        returnTokens.toArray(returnArray);
        return returnArray;
    }