void processLine(string line, Program & program, EvalState & state) {
TokenScanner scanner;
scanner.ignoreWhitespace();
scanner.scanNumbers();
scanner.setInput(line);
// Expression *exp = parseExp(scanner);
// int value = exp->eval(state);
// cout << value << endl;
// delete exp;
if (!scanner.hasMoreTokens()) {
return;
}
string firstToken = toUpperCase(scanner.nextToken());
if (firstToken == "RUN") {
runProgram(program, state);
}
else if (firstToken == "QUIT") {
exit(0);
}
else if (firstToken == "HELP") {
dspHelp();
}
else if (firstToken == "CLEAR") {
program.clear();
}
else if (firstToken == "LIST") {
listCmd(program);
}
else if (firstToken == "INPUT" || firstToken == "PRINT" || firstToken == "LET") {
scanner.saveToken(firstToken);
Statement * stmt = parseStatement(scanner);
stmt->execute(state);
delete stmt;
}
else {
int lineNumber = stringToInteger(firstToken);
if (!scanner.hasMoreTokens()) {
program.removeSourceLine(lineNumber);
}
else {
int length = firstToken.length();
string source = line.substr(length);
program.addSourceLine(lineNumber, source);
Statement * stmt = parseStatement(scanner);
program.setParsedStatement(lineNumber, stmt);
}
}
}
/* Function: sqrtFunction()
* -------------------------
* Library sqrt function execution. Expects for brackets and involves
* formulaStringScanning process for expression in brackets. Return sqrt function result
* for obtained value in brackets.
*
* @param scanner TokenScanner for user formula */
double sqrtFunction(TokenScanner& scanner) {
bool sqrtFailFlag = false;
string token = "";
double sqrtParam = 0;
if (scanner.hasMoreTokens()) {
token = scanner.nextToken();//waiting for brackets at this place
if (token == "(") {
bool bracketsOpened = true;
/* Calls internal scanFormulaString process for expression in brackets */
sqrtParam = scanFormulaString(scanner, bracketsOpened);
} else {
sqrtFailFlag = true;
}
}
if (sqrtFailFlag) {
cout << " - SQRT FUNCTION FAULT" << endl;
FAIL_FLAG = true;
return 0;
}
/* Returns sqrt function result */
return sqrt(sqrtParam);
}
/**
* Receive information from file, processes and displays the result on the screen.
*/
void processText(TokenScanner & scanner){
int counterSentences = 0;
int counterWords = 0;
int counterSyllable = 0;
double grade = 0.0;
scanner.ignoreWhitespace(); // ignores spaces
scanner.addWordCharacters("'"); // does part of the token is the character "'"
// processes each token
while (scanner.hasMoreTokens()){
string token = scanner.nextToken();
counterSentences += checkSentences(token);
if(checkWords(token)){
counterWords ++;
counterSyllable += colSyllable(token);
}
}
// If the file does not contain any words or sentences, assume that their one
if(counterWords == 0 || counterSentences == 0) counterSentences = counterWords = 1;
grade = getGrade(counterSentences, counterWords, counterSyllable);
cout << "Words : " << counterWords << endl;
cout << "Syllable : " << counterSyllable << endl;
cout << "Sentences : " << counterSentences << endl;
cout << "Grade : " << grade << endl;
}
bool isHaiku(string filename) {
fstream infile;
infile.open(filename.c_str());
string temp;
int count = 0;
TokenScanner scanner;
while(getline(infile, temp)){
count++;
int syllables = 0;
scanner.setInput(temp);
while (scanner.hasMoreTokens()){
syllables += syllablesIn(scanner.nextToken());
}
if((count == 1 || count ==3)&&syllables!=5){
infile.close();
return false;
}
if (count == 2 && syllables !=7){
infile.close();
return false;
}
if (count >3){
infile.close();
return false;
}
}
return true;
}
/* Function: powFunction()
* Usage: is called by formulaStringScanning() function if it detect pow token in formula
* -----------------------------------------------------------------------------------------//
* Library pow function execution. Believe that it's normalized function -
* without any variables like "x" or "y" - just pow(<value>, <power for value>):
* pow(2, 4) = 16
* Expects brackets, and return pow function result for values in brackets.
*
* @param scanner TokenScanner for user formula */
double powFunction(TokenScanner& scanner) {
bool powFail = false;
string token = "";
string num1 = "";
string num2 = "";
while(scanner.hasMoreTokens()) {
token = scanner.nextToken();//waiting for brackets at this place
if(token == "(") {
num1 = scanner.nextToken();//pow function param1
token = scanner.nextToken();//waiting coma at this place
if(token == ",") {
num2 = scanner.nextToken();//pow function param2
token = scanner.nextToken();//waiting for brackets at this place
if(token == ")") {
break;
} else {
powFail = true;
}
} else {
powFail = true;
}
} else {
powFail = true;
}
if(powFail) {
cout << " - POW FUNCTION INPUT FAULT!" << endl;
failFlag = true;
return 0;
}
}
/* Returns pow function result */
return pow(stringToDouble(num1), stringToDouble(num2));
}
/* Function: sqrtFunction()
* Usage: is called by formulaStringScanning() function if it detect sqrt token in formula
* -----------------------------------------------------------------------------------------//
* Library sqrt function execution. Expects for brackets and involves
* formulaStringScanning process for expression in brackets. Return sqrt function result
* for obtained value in brackets.
*
* @param scanner TokenScanner for user formula
* @param xValue Value for x variable in user equation */
double sqrtFunction(TokenScanner& scanner, double xValue) {
bool sqrtFail = false;
string token = "";
double num1 = 0;
if(scanner.hasMoreTokens()) {
token = scanner.nextToken();
if(token == "(") { //waiting for brackets at this place
bool bracketsOpened = true;
/* Calls internal formulaStringScanning process for expression in brackets */
num1 = formulaStringScanning(scanner,
bracketsOpened,
xValue);
} else {
sqrtFail = true;
}
}
if(sqrtFail) {
cout << " - SQRT FUNCTION FAULT" << endl;
failFlag = true;
return 0;
}
/* Returns sqrt function result */
return sqrt(num1);
}
/*
* Implementation notes: the InputStmt subclass
* ----------------------------------------------
* Instances of this class read the identifier from the scanner and notify
* the user if its format is illegal. In the execute method, it records
* the input of the user as the value of the identifier in "state".
*/
InputStmt::InputStmt(TokenScanner & scanner){
string nextToken = scanner.nextToken();
if (isdigit(nextToken[0]))
error("Invalid identifier for Input Statement -- can't start with an integer.");
if (scanner.hasMoreTokens())
error("Unexpected token: " + scanner.nextToken());
identifier = nextToken;
}
LetStmt::LetStmt(TokenScanner &scanner) {
identifier = scanner.nextToken();
op = scanner.nextToken();
exp = readE(scanner, 0);
if (scanner.hasMoreTokens()) {
error("Extraneous token " + scanner.nextToken());
}
}
/*
* Function: listProgram
* Usage: listProgram(program, scanner);
* -------------------------------------------
* Displays the lines of the program. It calls either version of program.toString()
* depending on whether the user specifies line numbers.
*/
void listProgram(Program & program, TokenScanner & scanner) {
if (!scanner.hasMoreTokens()) {
program.toString();
}
else {
int startLine = stringToInteger(scanner.nextToken());
scanner.nextToken();
int endLine = stringToInteger(scanner.nextToken());
program.toString(startLine, endLine);
}
}
IfStmt::IfStmt(TokenScanner &scanner) {
lhs = readE(scanner, 0);
op = scanner.nextToken();
rhs = readE(scanner, 0);
if (scanner.nextToken() != "THEN") {
error("Syntax error! Invalid IF statement!");
}
nextLine = stringToInteger(scanner.nextToken());
if (scanner.hasMoreTokens()) {
error("Extraneous token " + scanner.nextToken());
}
}
void processLine(string line, Program & program, EvaluationContext & context) {
TokenScanner scanner;
scanner.ignoreWhitespace();
scanner.setInput(line);
string firstToken = toUpperCase(scanner.nextToken());
if (firstToken == "RUN") {
runProgram(program, context);
}
else if (firstToken == "LIST") {
listProgram(program, scanner);
}
else if (firstToken == "CLEAR") {
program.clear();
}
else if (firstToken == "HELP") {
if (!scanner.hasMoreTokens()) {
displayHelp();
}
else {
specificHelp(scanner);
}
}
else if (firstToken == "QUIT") {
exit(0);
}
else {
int lineNumber = stringToInteger(firstToken);
if (!scanner.hasMoreTokens()) {
program.removeSourceLine(lineNumber);
}
else {
Statement *stmt = parseStatement(scanner);
program.addSourceLine(lineNumber, line);
program.setParsedStatement(lineNumber, stmt);
}
}
}
void toAlpha(std::string word, Map<std::string, std::string>& symbolTable) {
TokenScanner scanner;
scanner.ignoreWhitespace();
for(char i = 'A'; i < 'Z'; i++)
scanner.addWordCharacters(symbolTable.get(charToString(i)));
scanner.setInput(word);
while(scanner.hasMoreTokens()) {
std::string symbol = scanner.nextToken();
cout << symbolTable.get(symbol);
}
cout << endl;
}
void interpreter(void) {
std::string line;
TokenScanner scanner;
scanner.ignoreWhitespace();
scanner.scanNumbers();
Map<std::string, std::string> symbolTable;
cout << "Interpreter is running: " << endl;
// Main loop:
std::string key, value;
while(true) {
cout << "> ";
line = getLine();
if(line == "quit")
break;
else if(line == "list") {
for(std::string key : symbolTable) {
cout << key << " = " << symbolTable.get(key) << endl;
}
}
else if(symbolTable.containsKey(line))
cout << symbolTable.get(line) << endl;
// Parse statements:
else {
scanner.setInput(line);
bool isValue = false;
while(scanner.hasMoreTokens()) {
std::string token = scanner.nextToken();
if(isValue)
value = token;
else if(token == "=")
isValue = true;
else
key = token;
}
symbolTable.add(key, value);
}
}
cout << "Interpreter is stopped." << endl;
}
/* Function: powFunction()
* ------------------------
* Library pow function execution. Expects sequentally:
* - brackets, param1, coma, param2, brackets.
*
* @param scanner TokenScanner for user formula */
double powFunction(TokenScanner& scanner) {
bool powFailFlag = false;
string token = "";
string powParam_1 = ""; //pow function param1
string powParam_2 = ""; //pow function param2
while (scanner.hasMoreTokens()) {
token = scanner.nextToken();//waiting for brackets at this place
if (token == "(") {
powParam_1 = scanner.nextToken();
token = scanner.nextToken();//waiting for coma at this place
if (token == ",") {
powParam_2 = scanner.nextToken();
token = scanner.nextToken();//waiting for brackets - end of pow params input
if (token == ")") {
break;
} else {
powFailFlag = true;
}
} else {
powFailFlag = true;
}
} else {
powFailFlag = true;
}
if (powFailFlag) {
cout << " - POW FUNCTION INPUT FAULT!" << endl;
FAIL_FLAG = true;
return 0;
}
}
/* Returns pow function result */
double param1 = stringToDouble(powParam_1);
double param2 = stringToDouble(powParam_2);
return pow(param1, param2);
}
/* Function: scanFormulaString()
* -----------------------------
* Recursively scanns formula string and sorts each token through stacks due to shunting-yard
* algorithm. If "()" appear in this recursion it controls brackets condition. Detects two
* pow, sqrt - additional library function in user formula. Breaks process due to global
* failFlag. Returns double of calculated result. In case of process faults zero result
* is returned, and fail message is shown.
*
* @param scanner Scanner for main formula string
* @param bracketsOpenedBefore Brackets were opened before this recursion invocation */
double scanFormulaString(TokenScanner& scanner, bool& bracketsOpenedBefore) {
if (FAIL_FLAG) {
return 0; //Global flag apearance
}
Stack<double> numbersStack; //Stacks for Shunting-Yard process
Stack<string> operatorsStack; //in current recursion invocation
string token = "";
bool bracketsOpenedHere = false;//Rises if "(" appear in this recursion
/* Main string scanning. It stops due to conditions:
* - end of formula string
* - closed brackets condition
* - FAIL_FLAG appearance */
while (scanner.hasMoreTokens()) {
token = scanner.nextToken();
if (token == "pow") {
/* Lunches library pow function process */
double powResult = powFunction(scanner);
numbersStack.push(powResult);
}else if (token == "sqrt") {
/* Lunches library sqrt function process */
double sqrtResult = sqrtFunction(scanner);
numbersStack.push(sqrtResult);
}else{//Numbers, brackets or garbage symbol occur cases
if (token == "(") {
bracketsOpenedHere = true;
/* Calls new formula recursion for this scanner */
numbersStack.push(scanFormulaString(scanner, bracketsOpenedHere));
}else if (token == ")") {
if (bracketsOpenedBefore) { //Brackets are closed correctly
bracketsOpenedBefore = false;//it is end of this recursion
break;
}else {//Token is ")" and no bracketsOpenedBefore flag
FAIL_FLAG = true; //Brackets weren't opened
cout << " - NOT OPENED BRACKETS! " << endl;
break; //Break to show error to user
}
}else {
if (FAIL_FLAG) {
break;//Break if some faults appear in this recursion
}
/* Call Shunting-Yard sorting for this token */
sortTokenByStacks(token, numbersStack, operatorsStack);
}
}
}//End of while(scanner.hasMoreTokens())
/* Shunting-yard final calculation */
if (bracketsOpenedBefore) {//If brackets haven't been closed in this recursion
cout << " - NOT CLOSED BRACKETS! " << endl;
FAIL_FLAG = true;
return 0;
} else {
if (FAIL_FLAG) {//Main scanning cycle was breaked by some faults
return 0;
} else {
/* Final stacks processing */
return getFinalStacksResult(numbersStack, operatorsStack);
}
}
}
InputStmt::InputStmt(TokenScanner &scanner) {
identifier = scanner.nextToken();
if (scanner.hasMoreTokens()) {
error("Extraneous token " + scanner.nextToken());
}
}
/* Function: formulaStringScanning()
* -----------------------------------------------------------------------------------------//
* Recursively scanns formula string and sorts each token through stacks due to shunting-yard
* algorithm. If "()" appear in this recursion it controls brackets condition. Detects two
* pow, sqrt - additional library function in user formula. Breaks process due to global
* failFlag. Returns double of calculated result. In case of process faults zero result
* is returned, and fail message is shown.
*
* @param scanner Scanner for main formula string
* @param bracketsOpenedBefore Brackets were opened before this recursion invocation
* @param xValue Value for x variable in user equation */
double formulaStringScanning(TokenScanner& scanner,
bool &bracketsOpenedBefore,
double xValue) {
if(failFlag) {
return 0; //Global flag apearance
}
else {
MyStack<double> stackNumbers;//Stacks for current recursion invocation
MyStack<string> stackOperators;
string token = "";
bool bracketsOpenedHere = false;//Rises if "(" appear in this recursion
while(scanner.hasMoreTokens()) {
token = scanner.nextToken();
if(token == "x") {
/* Sabstitute x-token by user xValue param */
stackNumbers.push(xValue);
}
else if(token == "pow") {
/* Lunches library pow function process */
stackNumbers.push(powFunction(scanner));
} else if(token == "sqrt") {
/* Lunches library sqrt function process */
stackNumbers.push(sqrtFunction(scanner, xValue));
} else { //Brackets case
if(token == "(") {
bracketsOpenedHere = true;
/* Calls new formula recursion for this scanner */
stackNumbers.push(formulaStringScanning(scanner,
bracketsOpenedHere,
xValue));
} else if(token == ")") {
if(bracketsOpenedBefore) { //Brackets are closed correctly
bracketsOpenedBefore = false;//it is end of this recursion
break;
}
else { //Token is ")" and no bracketsOpenedBefore flag
failFlag = true; //Brackets were opened
cout << " - NOT OPENED BRACKETS! " << endl;
break; //Break to show error to user
}
} else {
if(failFlag)break;
/* If no fails, and token is valid - lunches
* Shunting-Yard sorting */
sortTokenByStacks(token, stackNumbers, stackOperators);
}
}//End of Brackets case else statement
}//End of while(scanner.hasMoreTokens())
/* Shunting-yard final calculation */
if(bracketsOpenedBefore) { //If brackets haven't been closed in this recursion
cout << " - NOT CLOSED BRACKETS! " << endl;
failFlag = true;
return 0;
} else {
if(failFlag) { //There were some other fails
return 0;
} else {
/* Calculate main result, due to stacks, for current calculation stage. */
return getFinalStacksResult(stackNumbers, stackOperators);
}
}
}//End of else statement (no failFlag at recursion start)
}
void processLine(string line, Program & program, EvalState & state) {
/* TokenScanner scanner;
scanner.ignoreWhitespace();
scanner.scanNumbers();
scanner.setInput(line);
Expression *exp = parseExp(scanner);
int value = exp->eval(state);
cout << value << endl;
delete exp;*/
TokenScanner scanner;
scanner.ignoreWhitespace();
scanner.scanNumbers();
scanner.setInput(line);
string token = scanner.nextToken();
TokenType type = scanner.getTokenType(token);
if (type == WORD){
if (token == "RUN")
{
int current_line=program.getFirstLineNumber();
while (current_line>=0)
{
int next_line = program.getNextLineNumber(current_line);
Statement* stat=program.getParsedStatement(current_line);
StatementType type = stat->get_type();
if (type == END)
break;
if (type == GOTO)
{
((Gotostmt*)stat)->execute(state,current_line);
continue;
}
if (type == IF)
{
((Ifstmt*)stat)->execute(state, current_line);
if (current_line != -2)
continue;
}
stat->execute(state);
current_line = next_line;
}
}
if (token == "QUIT")
{
exit(0);
}
if (token == "CLEAR")
{
program.clear();
EvalState state1;
state = state1;
}
if (token == "HELP")
{
}
if (token == "LIST")
{
int current_line = program.getFirstLineNumber();
while (current_line != -1)
{
cout << program.getSourceLine(current_line) << endl;
current_line = program.getNextLineNumber(current_line);
}
}
if (token == "INPUT"){
string st = scanner.nextToken();
if (scanner.hasMoreTokens())
error("SYNTAX ERROR");
Inputstmt inputst(st);
inputst.execute(state);
}
if (token == "PRINT"){
Printstmt printst(scanner);
printst.execute(state);
}
if (token == "LET")
{
Letstmt lets(scanner);
lets.execute(state);
}
if (token != "RUN"&&token != "CLEAR"&&token != "HELP"&&token != "LIST"&&token != "QUIT"&&token != "PRINT"&&token != "LET"&&token != "INPUT")
error("SYNTAX ERROR");
}
else if (type == NUMBER){
int line_num = atoi(token.c_str());
string token2 = scanner.nextToken();
if (token2 == "")
{
program.removeSourceLine(line_num);
return;
}
if (token2 == "REM")
{
string str, temp;
while (scanner.hasMoreTokens())
{
temp = scanner.nextToken();
str += temp;
}
Statement* remst = new Remstmt(str);
program.setParsedStatement(line_num, remst);
program.addSourceLine(line_num, line);
return;
}
if (token2 == "LET")
{
Statement *letst = new Letstmt(scanner);
program.setParsedStatement(line_num, letst);
program.addSourceLine(line_num, line);
return;
}
if (token2 == "PRINT")
{
Statement *printst = new Printstmt(scanner);
program.setParsedStatement(line_num, printst);
program.addSourceLine(line_num, line);
return;
}
if (token2 == "INPUT")
{
string st = scanner.nextToken();
if (scanner.hasMoreTokens())
error("SYNTAX ERROR");
Statement* inputstat = new Inputstmt(st);
program.setParsedStatement(line_num, inputstat);
program.addSourceLine(line_num, line);
return;
}
if (token2 == "GOTO")
{
string token_tmp = scanner.nextToken();
TokenType type = scanner.getTokenType(token_tmp);
if (type != NUMBER)
error("SYNTAX ERROR");
if (scanner.hasMoreTokens())
error("SYNTAX ERROR");
int linenum = atoi(token_tmp.c_str());
Statement* gotostat = new Gotostmt(linenum);
program.setParsedStatement(line_num, gotostat);
program.addSourceLine(line_num, line);
return;
}
if (token2 == "IF")
{
TokenScanner Lscanner;
TokenScanner Rscanner;
string left, right, tmp, cmp;
while (scanner.hasMoreTokens())
{
tmp = scanner.nextToken();
if (tmp == "=" || tmp == ">" || tmp == "<")
{
cmp = tmp;
break;
}
else left = left + tmp;
}
if (cmp != "="&&cmp != "<"&&cmp != ">")
error("SYNTAX ERROR");
while (scanner.hasMoreTokens())
{
tmp = scanner.nextToken();
if (tmp == "THEN")
break;
else right = right + tmp;
}
if (tmp != "THEN")
error("SYNTAX ERROR");
string token_tmp = scanner.nextToken();
TokenType type = scanner.getTokenType(token_tmp);
if (type != NUMBER)
error("SYNTAX ERROR");
if (scanner.hasMoreTokens())
error("SYNTAX ERROR");
int linenum = atoi(token_tmp.c_str());
Lscanner.setInput(left);
Rscanner.setInput(right);
Expression *lexp = parseExp(Lscanner);
Expression *rexp = parseExp(Rscanner);
Statement* ifstat = new Ifstmt(lexp, rexp, cmp, linenum);
program.setParsedStatement(line_num, ifstat);
program.addSourceLine(line_num, line);
return;
}
if (token2 == "END")
{
Statement* endstat=new Endstmt();
program.setParsedStatement(line_num, endstat);
program.addSourceLine(line_num, line);
return;
}
error("SYNTAX ERROR");
}
else error("SYNTAX ERROR");
}
/*
* Function: processLine
* Usage: processLine(line, program, state);
* -----------------------------------------
* Processes a single line entered by the user. In this version,
* the implementation does exactly what the interpreter program
* does in Chapter 19: read a line, parse it as an expression,
* and then print the result. In your implementation, you will
* need to replace this method with one that can respond correctly
* when the user enters a program line (which begins with a number)
* or one of the BASIC commands, such as LIST or RUN.
*/
void processLine(string line, Program & program, EvalState & state) {
TokenScanner scanner;
scanner.ignoreWhitespace();
scanner.scanNumbers();
scanner.setInput(line);
string token=scanner.nextToken();
TokenType type=scanner.getTokenType(token);
int lineNumb;
int priorLineNumb;
if(type==NUMBER){
if(scanner.hasMoreTokens()){
program.addSourceLine(stringToInteger(token),line);
Statement *stmt=parseStatement(scanner);
program.setParsedStatement(stringToInteger(token),stmt); //link statement to line number
}
else
program.removeSourceLine(stringToInteger(token));
}
if(type==WORD){
if(token=="LIST"){
lineNumb=program.getFirstLineNumber();
while(lineNumb!=-1){
cout<<program.getSourceLine(lineNumb)<<endl;
lineNumb=program.getNextLineNumber(lineNumb);
}
}
else if(token=="RUN"){
state.setCurrentLine(program.getFirstLineNumber());
lineNumb=state.getCurrentLine();
while(lineNumb!=-1){
if(program.hasLineNumber(lineNumb)==false)
error("Invalid line reference at program line "+integerToString(priorLineNumb));
Statement *stmt=program.getParsedStatement(lineNumb);
state.setCurrentLine(program.getNextLineNumber(lineNumb));
stmt->execute(state);
priorLineNumb=lineNumb;
lineNumb=state.getCurrentLine();
}
}
else if(token=="CLEAR"){
program.clear();
}
else if(token=="HELP"){
cout<<"Minimal Basic Statements"<<endl;
cout<<"REM This statement used for comments"<<endl;
cout<<"LET This statement is BASIC's assigment statement"<<endl;
cout<<"PRINT In minimal BASIC, the PRINT statement has the form: "<<endl;
cout<<" PRINT exp"<<endl;
cout<<" where exp is an expression."<<endl;
cout<<"INPUT In the minimal version of the BASIC interpreter, the INPUT statement has the form:"<<endl;
cout<<" INPUT var"<<endl;
cout<<" where var is a variable read in from the user"<<endl;
cout<<"GOTO This statement has the syntax"<<endl;
cout<<" GOTO n"<<endl;
cout<<" which forces the program to continue from line n instead of continuing with the next statement"<<endl;
cout<<"IF This statement provides conditional control. The syntax for this statement is: "<<endl;
cout<<" IF exp1 op exp2 THEN n"<<endl;
cout<<" where exp1 and exp2 are expressions and op is one of the conditional operators =, <, or >."<<endl;
cout<<"END This statment marks the end of the program."<<endl;
cout<<"Commands to control the BASIC interpreter"<<endl;
cout<<"RUN This command starts program execution beginning at the lowest-numbered line. "<<endl;
cout<<"LIST This command lists the steps in the program in numerical sequence."<<endl;
cout<<"CLEAR This command deletes the program so the user can start entering a new one."<<endl;
cout<<"HELP This command provides a simple help message describing the interpreter."<<endl;
cout<<"QUIT Typing QUIT exits from the BASIC interpreter by calling exit(0)."<<endl;
}
else if(token=="QUIT"){
exit(0);
}
else
cout<<"Invalid command"<<endl;
}
}
EndStmt::EndStmt(TokenScanner &scanner) {
if (scanner.hasMoreTokens()) {
error("Extraneous token " + scanner.nextToken());
}
}
/* main() manages the user interface;
* instantiates priority queue object, then operates loop to read input
* from user and call the appropriate priority queue method
*/
int main() {
PriorityQueue pq;
TokenScanner scanner;
while (true) {
string line = getLine("> ");
scanner.setInput(line);
scanner.ignoreWhitespace();
string cmd=scanner.nextToken();
if (cmd == "help") {
helpCommand();
}
else if (cmd == "enqueue") {
if(scanner.hasMoreTokens()){
string value=scanner.nextToken();
if(scanner.hasMoreTokens()){
scanner.scanNumbers();
string priorityStr=scanner.nextToken();
double priority=stringToDouble(priorityStr);
pq.enqueue(value,priority);
}
else
pq.enqueue(value);
}
}
else if (cmd == "dequeue") {
if(pq.isEmpty())
cout<<"The queue is empty"<<endl;
else
cout<<pq.dequeue()<<endl;
}
else if (cmd == "peek") {
if(pq.isEmpty())
cout<<"The queue is empty"<<endl;
else
cout<<pq.peek()<<endl;
}
else if (cmd == "peekPriority"||cmd=="peekpriority") {
if(pq.isEmpty())
cout<<"The queue is empty"<<endl;
else
cout<<pq.peekPriority()<<endl;
}
else if (cmd == "clear") {
pq.clear();
}
else if (cmd == "size") {
cout<<pq.size()<<endl;
}
else if (cmd == "isEmpty"||cmd=="isempty") {
if(pq.isEmpty())
cout<<"true";
else
cout<<"false";
cout<<endl;
}
else if(cmd=="list")
list(pq);
else {
cout << "Undefined command: " << cmd << endl;
}
}
return 0;
}
/*
* Implementation notes: the PrintStmt subclass
* ----------------------------------------------
* Instances of this class evaluate the expression that is passed
* to them through the scanner and then print the result using the
* excecute method.
*/
PrintStmt::PrintStmt(TokenScanner & scanner) {
exp = readE(scanner, 0);
if (scanner.hasMoreTokens()) {
error("Extraneous token " + scanner.nextToken());
}
}
GotoStmt::GotoStmt(TokenScanner &scanner) {
lineNumber = stringToInteger(scanner.nextToken());
if (scanner.hasMoreTokens()) {
error("Extraneous token " + scanner.nextToken());
}
}