stage1.cpp

#include "stage1.h"
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <fstream>
#include <iomanip>
#include <iostream>
#include <string>

// Kangmin Kim and Jeff Caldwell
// CS 4301
// Compiler - Stage1

Compiler::Compiler(char **argv) // constructor
{
  sourceFile.open(argv[ 1 ]);  // open sourceFile using argv[1] (input from argv[1])
  listingFile.open(argv[ 2 ]); // open listingFile using argv[2] (generate a
  // listing to argv[2])
  objectFile.open(argv[ 3 ]); // open objectFile using argv[3] (write object code to argv[3])
}

Compiler::~Compiler() //  close all open files
{
  sourceFile.close();
  listingFile.close();
  objectFile.close();
}

void Compiler::createListingHeader() // destructor
{
  // print "STAGE1:", name(s), DATE, TIME OF DAY
  // print "LINE NO:", "SOURCE STATEMENT"
  time_t now = time(0);

  // line numbers and source statements should be aligned under the headings
  listingFile << "STAGE1:  "
    << "Jeff Caldwell, Kangmin Kim       " << ctime(&now) << "\n";
  listingFile << "LINE NO."
    << "               SOURCE STATEMENT\n\n";
}
// private: uint lineNo = 0; // line numbers for the listing

void Compiler::parser()
{
  nextChar(); // returns the next character or end of file marker

  // ch must be initialized to the first character of the source file
  if (nextToken() != "program") // string nextToken() returns the next token or
    // END_OF_FILE marker
  {
    processError("keyword \"program\" expected"); // Output err to listingFile
    // Call exit() to terminate program
  }
  // a call to nextToken() has two effects
  // (1) the variable, token, is assigned the value of the next token
  // (2) the next token is read from the source file in order to make
  // the assignment. The value returned by nextToken() is also
  // the next token.
  prog();
  // parser implements the grammar rules, calling first rule
}

void Compiler::createListingTrailer()
{
  listingFile << "\nCOMPILATION TERMINATED" << setw(6) << "" << right << errorCount
    << (errorCount != 1 ? " ERRORS " : " ERROR ") << "ENCOUNTERED\n";
}
// private: uint errorCount = 0; // total number of errors encountered

void Compiler::processError(string error)
{
  listingFile << "\n"
    << "Error: Line " << lineNo << ": " << error << "\n";
  errorCount++;
  createListingTrailer();
  // close files to ensure output will be written
  // calling exit() before closing the files seems
  // to preempt writing to them
  listingFile.close();
  objectFile.close();
  exit(EXIT_FAILURE);
}
/*
  Note that insert() calls genInternalName(), a function that has one argument,
  the type of the name being inserted. genInternalName() returns a unique
  internal name each time it is called, a name that is known to be a valid
  symbolic name. As a visual aid, we use different forms of internal names for
  each data-type of interest. The general form is: dn where d denotes the
  data-type of the name ("I" for integer, "B" for boolean) and n is a
  non-negative integer starting at 0. The generated source code for 001.dat
  clearly shows the effects of calling genInternalName(). The compiler itself
  will also need to generate names to appear in the object code, but since the
  compiler is defining these itself, there is no need to convert these names
  into any other form. The external and internal forms will be the same. The
  code for insert() treats any external name beginning with an uppercase
  character as defined by the compiler.
*/
string Compiler::genInternalName(storeTypes storeType) const
{
  static int I = 0; // integer
  static int B = 0; // boolean
  static int U = 0; // unknown
  string internalName;

  if (storeType == PROG_NAME)
  {
    internalName = "P0";
  }
  else if (storeType == INTEGER)
  {
    internalName = "I" + to_string(I);
    I++;
  }

  else if (storeType == BOOLEAN)
  {
    internalName = "B" + to_string(B);
    B++;
  }
  else if (storeType == UNKNOWN)
  {
    internalName = "U" + to_string(U);
    U++;
  }

  return internalName;
}

/** STAGE 0 PRODUCTIONS **/

void Compiler::prog() // stage 0, production 1
{                     // 1. PROG → PROG_STMT CONSTS VARS BEGIN_END_STMT
  if (token != "program")
  {
    processError("keyword \"program\" expected");
  }

  progStmt();

  if (token == "const")
  {
    consts();
  }

  if (token == "var")
  {
    vars();
  }

  if (token != "begin")
  {
    processError("keyword \"begin\" expected");
  }

  beginEndStmt();

  if (token[ 0 ] != END_OF_FILE)
  {
    processError("no text may follow \"end\"");
  }
}

void Compiler::progStmt() // 2. PROG_STMT → 'program' NON_KEY_IDx ';'
{                         //    code(’program’, x); insert(x,PROG_NAME,CONSTANT,x,NO,0)
  string x;               //    → 'program' NON_KEY_IDx ';'

  if (token != "program")
  {
    processError("keyword \"program\" expected");
  }

  x = nextToken(); // program name

  if (!isNonKeyId(token))
  {
    processError("program name expected");
  }

  if (nextToken() != ";")
  {
    processError("semicolon expected");
  }

  nextToken();
  code("program", x);
  insert(x, PROG_NAME, CONSTANT, x, NO, 0);
}

void Compiler::consts() // 3. CONSTS → 'const' CONST_STMTS
{                       //   → ε
  if (token != "const")
  {
    processError("keyword \"const\" expected");
  }
  if (!isNonKeyId(nextToken()))
  {
    processError("non-keyword identifier must follow \"const\"");
  }
  constStmts();
}

void Compiler::vars() // 4. VARS → 'var' VAR_STMTS
{                     //   → ε
  if (token != "var")
  {
    processError("keyword \"var\" expected");
  }

  if (!isNonKeyId(nextToken()))
  {
    processError("non-keyword identifier must follow \"var\"");
  }
  varStmts();
}

void Compiler::beginEndStmt()
{
  if (token != "begin")
  {
    processError("keyword \"begin\" expected");
  }

  nextToken();

  if (isNonKeyId(token) || token == "begin" || token == "read" || token == "write" || token == ";")
  {
    execStmts();
  }

  if (token != "end")
  {
    processError("keyword \"end\" expected");
  }

  if (nextToken() != ".")
  {
    processError("period expected");
  }

  nextToken();

  code("end", ".");
}

void Compiler::constStmts() // 6. CONST_STMTS → NON_KEY_IDx '='( NON_KEY_IDy |
// 'not' NON_KEY_IDy | LITy ) ';'
{              //   insert(x,whichType(y),CONSTANT,whichValue(y),YES,1)
  string x, y; //   ( CONST_STMTS | ε )

  if (!isNonKeyId(token))
  {
    processError("non-keyword identifier expected");
  }

  // check for illegal '_' at end of variable name
  if (token.back() == '_')
  {
    processError("illegal character '_'");
  }

  // check for '__' in middle of var/const
  if (token.find("__") != string::npos)
  {
    processError("illegal character '_'");
  }

  x = token;

  if (nextToken() != "=")
  {
    processError("\"=\" expected");
  }

  y = nextToken();

  if (y != "+" && y != "-" && y != "not" && !(isNonKeyId(y)) && !(isBoolean(y)) && !(isInteger(y)))
  {
    processError("token to right of \"=\" illegal");
  }

  if (y == "+" || y == "-")
  {
    string next = nextToken();

    if (!isInteger(next))
    {
      processError("integer expected after sign");
    }
    y = y + token;
  }

  if (y == "not")
  {
    nextToken();

    if (isBoolean(token) || isNonKeyId(token))
    {
      if (token == "true")
      {
        y = "false";
      }
      else if (token == "false")
      {
        y = "true";
      }
      else if (isNonKeyId(token))
      {
        if (symbolTable.at(token).getDataType() != BOOLEAN)
        {
          processError("boolean expected after \"not\"");
        }
        else
        {
          y = (symbolTable.at(token).getValue() == "0") ? "true" : "false";
        }
      }
    }
    else
    {
      processError("boolean expected after \"not\"");
    }
  }

  if (nextToken() != ";")
  {
    processError("semicolon expected");
  }

  storeTypes currentType = whichType(y);

  if (currentType != INTEGER && currentType != BOOLEAN)
  {
    processError("data type of token on the right - hand side must be INTEGER "
                 "or BOOLEAN");
  }

  insert(x, whichType(y), CONSTANT, whichValue(y), YES, 1);

  x = nextToken();

  if (x != "begin" && x != "var" && !(isNonKeyId(x)))
  {
    processError("non - keyword identifier, \"begin\", or \"var\" expected");
  }

  if (isNonKeyId(x))
  {
    constStmts();
  }
}

void Compiler::varStmts() // token should be NON_KEY_ID
{
  string x, y;
  if (!isNonKeyId(token))
  {
    processError("non-keyword identifier expected");
  }

  // check for illegal '_' at end of variable name
  if (token.back() == '_')
  {
    processError("illegal character '_'");
  }

  // check for '__' in middle of var/const
  if (token.find("__") != string::npos)
  {
    processError("illegal character '_'");
  }

  x = ids();

  if (token != ":")
  {
    processError("\":\" expected");
  }

  if (nextToken() != "integer" && token != "boolean")
  {
    processError("illegal type follows \":\"");
  }

  y = token;

  if (nextToken() != ";")
  {
    processError("semicolon expected");
  }

  if (y == "integer")
  {
    insert(x, INTEGER, VARIABLE, "1", YES, 1);
  }
  else
  {
    insert(x, BOOLEAN, VARIABLE, "1", YES, 1);
  }

  if (nextToken() != "begin" && !(isNonKeyId(token)))
  {
    processError("non-keyword identifier or \"begin\" expected");
  }

  if (isNonKeyId(token))
  {
    varStmts();
  }
}

string Compiler::ids() // 8. IDS → NON_KEY_ID ( ',' IDS | ε )
{
  string temp, tempString;

  if (!isNonKeyId(token))
  {
    processError("non-keyword identifier expected");
  }

  tempString = token;
  temp = token;

  if (nextToken() == ",")
  {
    if (!isNonKeyId(nextToken()))
    {
      processError("non-keyword identifier expected");
    }

    tempString = temp + "," + ids();
  }
  return tempString;
}

/** STAGE 1 PRODUCTIONS **/
void Compiler::execStmts() // -> EXEC_STMT | EXEC_STMTS
{                          // -> ε
  if (isNonKeyId(token) || token == "read" || token == "write" || token == ";")
  {
    execStmt();  // token will be at end of last exec statement
    nextToken(); // advance token
    execStmts(); // recurse
  }
  else if (token == "end");

  else
  {
    processError("\";\", \"begin\", \"read\",\"write\", \"end\" expected");
  }
}

void Compiler::execStmt()
{
  if (isNonKeyId(token)) // assignment statement
  {
    // cout << "assignment token: " << token << "\n";
    assignStmt();
  }

  else if (token == "read") // read statement
  {
    // cout << "read token: " << token << "\n";
    readStmt();
  }

  else if (token == "write") // write statement
  {
    // cout << "write token: " << token << "\n";
    writeStmt();
  }

  else
  { // error
    processError("non-keyword id, \"read\", or \"write\" expected");
  }
}

void Compiler::assignStmt()
{
  string op2, op1;
  if (!isNonKeyId(token))
  {
    processError("non - keyword identifier expected");
  }
  //Token must be defined
  if (symbolTable.count(token) == 0)
  {
    processError("reference to undefined variable");
  }

  pushOperand(token);

  nextToken();

  if (token != ":=")
  {
    processError("':=' expected; found " + token);
  }
  else
  {
    pushOperator(token);
    // pushOperator(":=");
  }
  nextToken();

  if (token != "not" && !isBoolean(token) && token != "(" && token != "+" && !isInteger(token)
     && token != "-" && !isNonKeyId(token) && token != ";")
  {
    processError("one of \"*\", \"and\", \"div\", \"mod\", \")\", \"+\", \"-\", \";\", \"<\", \"<=\", \"<>\", \"=\", \">\", \">=\", or \"or\" expected");
  }
  else
  {
    express();
  }
  op2 = popOperand();
  op1 = popOperand();
  code(popOperator(), op2, op1);
}

void Compiler::readStmt()
{
  string list;          // read list
  string listItem = ""; // list item
  uint i;               // list counter

  // double check for "read" token
  if (token != "read")
  {
    processError("keyword \"read\" expected");
  }

  // We have a read token. Advance to next token.
  nextToken();

  // Make sure it's a "("
  if (token != "(")
  {
    processError("\"(\" expected");
  }

  else
  {
    // We have a left paren. Advance token.
    nextToken();

    // collect non token ids, will advance token
    list = ids();

    // loop through the characters of the list
    for (i = 0; i < list.length(); i++)
    {
      if (list[ i ] == ',')
      {
        // if we have a ',', code current list item
        code("read", listItem);

        // reset list item for next characters
        listItem = "";
      }
      else
      {
        // if we don't have a ',', add characters to the list item
        listItem += list[ i ];
      }
    }

    // code current list item
    code("read", listItem);

    // look for a right paren
    // call to ids() advanced token, so no need to advance now
    if (token != ")")
    {
      processError("',' or ')' expected after non-keyword identifier");
    }

    // advance token
    nextToken();

    // check for semicolon
    if (token != ";")
    {
      processError("';' expected");
    }
  }
}

void Compiler::writeStmt()
{
  string list;          // read list
  string listItem = ""; // list item
  uint i;               // list counter

  // double check for "write" token
  if (token != "write")
  {
    processError("keyword \"write\" expected");
  }

  // We have a write token. Advance to next token.
  nextToken();

  // Make sure it's a "("
  if (token != "(")
  {
    processError("\"(\" expected");
  }

  // We have a left paren. Advance token.
  nextToken();

  // collect non token ids, will advance token
  list = ids();

  // loop through the characters of the list
  for (i = 0; i < list.length(); i++)
  {
    if (list[ i ] == ',')
    {
      // if we have a ',', code current list item
      code("write", listItem);

      // reset list item for next characters
      listItem = "";
    }
    else
    {
      // if we don't have a ',', add characters to the list item
      listItem += list[ i ];
    }
  }

  // code current list item
  code("write", listItem);

  // look for a right paren
  // call to ids() advanced token, so no need to advance now
  if (token != ")")
  {
    processError("',' or ')' expected after non-keyword identifier");
  }

  // advance token
  nextToken();

  // check for semicolon
  if (token != ";")
  {
    processError("';' expected");
  }

}

// stage 1, production 9
void Compiler::express()
{
  if (token != "(" && !isBoolean(token) && token != "not" && token != "+" && token != "-" && !isInteger(token) && !isNonKeyId(token))
  {
    processError("\"not\", \"true\", \"false\", \"(\", \"+\", \"-\", non - keyword identifier or integer expected");
  }

  term();

  if (token == "=" || token == "<" || token == ">" || token == ">=" || token == "<=" || token == "<>")
  {
    expresses();
  }
}

// stage 1, production 10
void Compiler::expresses()
{
  string x = "";
  string op1, op2;
  if (token != "=" && token != "<" && token != ">" && token != "<>" && token != "<=" && token != ">=")
  {
    processError("\"=\", \"<>\", \"<=\", \">=\", \"<\", or \">\" expected");
  }
  pushOperator(token);
  nextToken();

  if (!isBoolean(token) && !isInteger(token) && !isNonKeyId(token) && token != "+" && token != "not"
    && token != "-" && token != "(")
  {
    processError("\"not\", \"true\", \"false\", \"(\", \"+\", \"-\", integer, or non - keyword identifier expected");
  }
  else
  {
    term();
  }
  op1 = popOperand();
  op2 = popOperand();

  code(popOperator(), op1, op2);

  if (token == "<>" || token == "<" || token == ">" || token == "=" || token == "<=" || token == ">=")
  {
    expresses();
  }
}

// stage 1, production 11
void Compiler::term()
{
  if (token != "not" && !isBoolean(token) && token != "(" && token != "+"
    && token != "-" && !isInteger(token) && !isNonKeyId(token))
  {
    processError("\"not\", \"true\", \"false\", \"(\", \"+\", \"-\", integer, or non - keyword identifier expected");
  }
  factor();

  if (token == "-" || token == "or" || token == "+")
  {
    terms();
  }
}

// stage 1, production 12
void Compiler::terms()
{
  string x = "";
  string op1, op2;

  if (token != "or" && token != "+" && token != "-")
  {
    processError("\"+\", \"-\", or \"or\" expected");
  }
  pushOperator(token);
  nextToken();

  if (token != "-" && !isInteger(token) && !isNonKeyId(token)
    && token != "not" && !isBoolean(token) && token != "(" && token != "+")
  {
    processError("\"not\", \"true\", \"false\", \"(\", \"+\", \"-\", integer, or non - keyword identifier expected");
  }
  else
  {
    factor();
  }
  op1 = popOperand();
  op2 = popOperand();
  code(popOperator(), op1, op2);

  if (token == "-" || token == "+" || token == "or")
  {
    terms();
  }
}

// stage 1, production 13
void Compiler::factor()
{
  if (token != "-" && !isInteger(token) && !isNonKeyId(token) && token != "not"
    && !isBoolean(token) && token != "(" && token != "+")
  {
    processError("\"not\", \"true\", \"false\", \"(\", \"+\", \"-\", integer, or non - keyword identifier expected");
  }

  part();

  if (token == "*" || token == "mod" || token == "and" || token == "div")
  {
    factors();
  }
  if (token == ")" || token == ";" || token == "-" || token == "+" || token == "or" || token == "begin" ||
    token == "=" || token == "<>" || token == "<=" || token == ">=" || token == "<" || token == ">")
  {
    return;
  }
  else
  {
    processError("one of \"*\", \"and\", \"div\", \"mod\", \")\", \"+\", \"-\", \";\", \"<\", \"<=\", \"<>\", \"=\", \">\", \">=\", or \"or\" expected");
  }
}

// stage 1, production 14
void Compiler::factors()
{
  string x = "";
  string op1, op2;
  if (token != "*" && token != "mod" && token != "div" && token != "and")
  {
    processError("\"*\", \"div\", \"mod\", or \"and\" expected");
  }
  pushOperator(token);
  nextToken();

  if (token != "not" && !isBoolean(token) && !isInteger(token) && !isNonKeyId(token) && token != "+" && token != "-" && token != "(")
  {
    processError("\"not\", \"true\", \"false\", \"(\", \"+\", \"-\", integer, or non - keyword identifier expected");
  }
  else
  {
    part();
  }
  op1 = popOperand();
  op2 = popOperand();
  code(popOperator(), op1, op2);
  if (token == "*" || token == "mod" || token == "and" || token == "div")
  {
    factors();
  }
}

// stage 1, production 15
void Compiler::part()
{
  string x = "";
  if (token == "not")
  {
    nextToken();
    if (token == "(")
    {
      nextToken();
      if (token != "-" && !isInteger(token) && !isNonKeyId(token) && token != "not"
        && !isBoolean(token) && token != "(" && token != "+")
      {
        processError("\"not\", \"true\", \"false\", \"(\", \"+\", \"-\", integer, or non - keyword identifier expected");
      }
      express();
      if (token != ")")
      {
        processError(") expected; found " + token);
      }
      nextToken();
      code("not", popOperand());
    }

    else if (isBoolean(token))
    {
      if (token == "true")
      {
        pushOperand("false");
        nextToken();
      }
      else
      {
        pushOperand("true");
        nextToken();
      }
    }

    else if (isNonKeyId(token))
    {
      code("not", token);
      nextToken();
    }
  }

  else if (token == "+")
  {
    nextToken();
    if (token == "(")
    {
      nextToken();
      if (token != "-" && !isInteger(token) && !isNonKeyId(token)
        && !isBoolean(token) && token != "not" && token != "(" && token != "+")
      {
        processError("\"not\", \"true\", \"false\", \"(\", \"+\", \"-\", integer, or non - keyword identifier expected");
      }
      express();
      if (token != ")")
      {
        processError("expected ')'; found " + token);
      }
      nextToken();
    }
    else if (isInteger(token) || isNonKeyId(token))
    {
      pushOperand(token);
      nextToken();
    }

    else
    {
      processError("expected '(', integer, or non-keyword id; found " + token);
    }
  }

  else if (token == "-")
  {
    nextToken();
    if (token == "(")
    {
      nextToken();
      if (token != "-" && !isInteger(token) && !isNonKeyId(token) && token != "not"
        && !isBoolean(token) && token != "(" && token != "+")
      {
        processError("\"not\", \"true\", \"false\", \"(\", \"+\", \"-\", integer, or non - keyword identifier expected");
      }
      express();
      if (token != ")")
      {
        processError("expected ')'; found " + token);
      }
      nextToken();
      code("neg", popOperand());
    }
    else if (isInteger(token))
    {
      pushOperand("-" + token);
      nextToken();
    }
    else if (isNonKeyId(token))
    {
      code("neg", token);
      nextToken();
    }
  }

  else if (token == "(")
  {
    nextToken();
    if (!isInteger(token) && !isBoolean(token) && !isNonKeyId(token) && token != "(" && token != "+"
      && token != "-" && token != "not")
    {
      processError("\"not\", \"true\", \"false\", \"(\", \"+\", \"-\", integer, or non - keyword identifier expected");
    }
    express();
    if (token != ")")
    {
      processError(") expected; found " + token);
    }
    nextToken();
  }

  else if (isNonKeyId(token) || isInteger(token) || isBoolean(token))
  {
    pushOperand(token);
    nextToken();
  }

  else
  {
    processError("\"not\", \"true\", \"false\", \"(\", \"+\", \"-\", integer, boolean, or non - keyword identifier expected");
  }
}

/** END PRODUCTIONS **/

/** STACK FUNCTIONS **/

void Compiler::pushOperator(string op)
{
  operatorStk.push(op);
}

string Compiler::popOperator() // pop name from operatorStk
{
  string op;

  if (!operatorStk.empty())
  {
    op = operatorStk.top();
    operatorStk.pop();
  }
  else
  {
    processError("operator stack underflow");
  }
  return op;
}

void Compiler::pushOperand(string op) // push name onto operatorStk
{
  if (symbolTable.count(op) == 0)
  {
    if (isInteger(op) || isBoolean(op))
    {
      insert(op, whichType(op), CONSTANT, whichValue(op), YES, 1);
    }
  }
  operandStk.push(op);
}

string Compiler::popOperand() // pop name from operandStk
{
  string op;
  if (!operandStk.empty())
  {
    op = operandStk.top();
    operandStk.pop();
  }
  else
  {
    processError("operand stack underflow");
  }

  return op;
}

void Compiler::freeTemp()
{
  currentTempNo--;
  if (currentTempNo < -1)
  {
    processError("compiler error: currentTempNo should be greater than or equal to –1");
  }
}

string Compiler::getTemp()
{
  currentTempNo++;
  string temp;

  temp = "T" + to_string(currentTempNo);

  if (currentTempNo > maxTempNo)
  {
    insert(temp, UNKNOWN, VARIABLE, "1", NO, 1);
    symbolTable.at(temp).setInternalName(temp);
    maxTempNo++;
  }

  return temp;
}

string Compiler::getLabel()
{
  string internalName; // Label
  static int L = 0;

  internalName = "L" + to_string(L);

  L++;

  return internalName;
}
bool Compiler::isTemporary(string s) const
{
  if (s[ 0 ] == 'T')
    return true;
  else
    return false;
}

/** TYPE CHECKING FUNCTIONS **/
bool Compiler::isKeyword(string s) const
{

  // instead of using a crazy, long string of conditional operators (||),
  // just make an array and loop through that
  string keywords[ 16 ] = {"program", "const", "var", "integer", "boolean", "begin", "end", "true",
    "false", "not", "mod", "div", "and", "or", "read", "write"};

  int len = *(&keywords + 1) - keywords; // length of keywords

  for (int i = 0; i < len; i++)
  {
    if (keywords[ i ] == s)
    {
      return true;
    }
  }

  return false;
}

bool Compiler::isSpecialSymbol(char c) const
{
  char symbols[ 12 ] = {':', ',', ';', '=', '+', '-', '.', '*', '(', ')', '>', '<'};

  int len = *(&symbols + 1) - symbols;

  for (int i = 0; i < len; i++)
  {
    if (symbols[ i ] == c)
    {
      return true;
    }
  }

  return false;
}

bool Compiler::isInteger(string s) const
{
  // Check for '+' or '-' without digits
  if (s.length() == 1)
  {
    if (s == "+" || s == "-")
    {
      return false;
    }
  }

  for (uint i = 0; i < s.length(); i++)
  {
    // if the first character is not a '+' or a '-'
    // of if any character is not a digit, it is not an integer
    if (!(isdigit(s[ i ]) || s[ 0 ] == '+' || s[ 0 ] == '-'))
    {
      return false;
    }
  }

  // if we made it this far we have an integer
  return true;
}

bool Compiler::isBoolean(string s) const
{
  if (s == "true" || s == "false")
  {
    return true;
  }
  else
  {
    return false;
  }
}

bool Compiler::isLiteral(string s) const // 10. LIT → INTEGER | BOOLEAN | 'not'
// BOOLEAN | '+' INTEGER | '-' INTEGER
{
  if (isInteger(s) || isBoolean(s) || s.front() == '+' || s.front() == '-' || s == "not")
  {
    return true;
  }

  return false;
}

bool Compiler::isNonKeyId(string s) const
{
  if (!isInteger(s) && !isKeyword(s) && !isSpecialSymbol(s[ 0 ]))
  {
    return true;
  }

  return false;
}

/** ACTION ROUTINES **/

void Compiler::insert(string externalName, // create symbol table entry for each identifier in list
                      storeTypes inType,   // of external names
                      modes inMode,        // Multiple inserted names are illegal
                      string inValue, allocation inAlloc, int inUnits)
{
  string name;
  uint i = 0;

  while (i < externalName.length())
  {
    name = "";

    while (i < externalName.length() && externalName[ i ] != ',')
    {
      name = name + externalName[ i ];
      i++;
    }

    if (!name.empty())
    {
      if (symbolTable.find(name) != symbolTable.end())
      {
        processError("symbol " + name + " is multiply defined");
      }
      else if (isKeyword(name) && !isBoolean(name))
      {
        processError("illegal use of " + name + " keyword"); // do we need to look out for booleans?
      }
      else
      {
        if (isupper(name[ 0 ]))
        {
          symbolTable.insert({name.substr(0, 15), SymbolTableEntry(name, inType, inMode, inValue, inAlloc, inUnits)});
        }
        else if (name == "true")
        {
          symbolTable.insert({name.substr(0, 15), SymbolTableEntry("TRUE", inType, inMode, inValue, inAlloc, inUnits)});
        }
        else if (name == "false")
        {
          symbolTable.insert(
              {name.substr(0, 15), SymbolTableEntry("FALSE", inType, inMode, inValue, inAlloc, inUnits)});
        }
        else
        {
          symbolTable.insert({name.substr(0, 15),
                              SymbolTableEntry(genInternalName(inType), inType, inMode, inValue, inAlloc, inUnits)});
        }
      }
    }

    if (symbolTable.size() > 256)
    {
      processError("symbol table overflow");
    }
    if (i == externalName.length())
    {
      break;
    }
    i++;
  }
}

storeTypes Compiler::whichType(string name) // tells which data type a name has
{                                           // 9. TYPE → 'integer'
  storeTypes type;                          //		  → 'boolean'

  if (isLiteral(name))
  {
    if (isInteger(name))
    {
      type = INTEGER;
    }
    else if (isBoolean(name))
    {
      type = BOOLEAN;
    }
  }
  else // name is an identifier and hopefully a constant
  {
    if (symbolTable.find(name) != symbolTable.end())
    {
      type = symbolTable.find(name)->second.getDataType();
    }
    else
    {
      processError("variable " + name + " is undefined");
    }
  }
  return type;
}

string Compiler::whichValue(string name) // tells which value a name has
{
  string value;
  if (isLiteral(name))
  {
    if (name == "false")
    {
      value = "0";
    }
    else if (name == "true")
    {
      value = "-1";
    }
    else
      value = name;
  }
  else // name is an identifier and hopefully a constant
  {
    if (symbolTable.find(name) != symbolTable.end())
    {
      value = symbolTable.at(name).getValue();
    }
    else
    {
      processError("constant " + name + " is undefined");
    }
  }
  return value;
}

/** EMIT FUNCTIONS **/

void Compiler::code(string op, string operand1, string operand2)
{
  if (op == "program")
  {
    emitPrologue(operand1);
  }
  else if (op == "end")
  {
    emitEpilogue();
  }
  else if (op == "read")
  {
    emitReadCode(operand1);
  }
  else if (op == "write")
  {
    emitWriteCode(operand1);
  }
  else if (op == "+")
  { // binary plus
    emitAdditionCode(operand1, operand2);
  }
  else if (op == "-")
  { // binary minus
    emitSubtractionCode(operand1, operand2);
  }
  else if (op == "neg")
  { // unary minus
    emitNegationCode(operand1);
  }
  else if (op == "not")
  {
    emitNotCode(operand1);
  }
  else if (op == "*")
  {
    emitMultiplicationCode(operand1, operand2);
  }
  else if (op == "div")
  {
    emitDivisionCode(operand1, operand2);
  }
  else if (op == "mod")
  {
    emitModuloCode(operand1, operand2);
  }
  else if (op == "and")
  {
    emitAndCode(operand1, operand2);
  }
  else if (op == "=")
  {
    emitEqualityCode(operand1, operand2);
  }
  else if (op == "<>")
  {
    emitInequalityCode(operand1, operand2);
  }
  else if (op == "or")
  {
    emitOrCode(operand1, operand2);
  }
  else if (op == "<")
  {
    emitLessThanCode(operand1, operand2);
  }
  else if (op == ">")
  {
    emitGreaterThanCode(operand1, operand2);
  }
  else if (op == "<=")
  {
    emitLessThanOrEqualToCode(operand1, operand2);
  }
  else if (op == ">=")
  {
    emitGreaterThanOrEqualToCode(operand1, operand2);
  }
  else if (op == ":=")
  {
    emitAssignCode(operand1, operand2);
  }
  else
  {
    processError("compiler error since function code should not be called with illegal arguments ");
  }
}

void Compiler::emit(string label, string instruction, string operands, string comment)
{
  // Turn on left justification in objectFile
  //   Output label in a field of width 8
  //   Output instruction in a field of width 8
  //   Output the operands in a field of width 24
  //   Output the comment
  objectFile << left << setw(8) << label;
  objectFile << setw(8) << instruction;
  objectFile << setw(24) << operands;
  objectFile << setw(8) << comment << '\n';
}

void Compiler::emitPrologue(string progName, string operand2)
{
  // Output identifying comments at beginning of objectFile
  //   Output the %INCLUDE directives
  //   emit("SECTION", ".text")
  //   emit("global", "_start", "", "; program" + progName)
  //   emit("_start:")

  time_t now = time(0);
  objectFile << "; Kangmin Kim, Jeff Caldwell       " << setw(8) << right << ctime(&now);
  objectFile << "%INCLUDE \"Along32.inc\"\n"
    << "%INCLUDE \"Macros_Along.inc\"\n\n";

  emit("SECTION", ".text");
  emit("global", "_start", "", "; program " + progName + "\n");
  emit("_start:");
}

void Compiler::emitEpilogue(string operand1, string operand2)
{
  emit("", "Exit", "{0}\n");
  emitStorage();
}

void Compiler::emitStorage()
{
  map<string, SymbolTableEntry>::iterator i;
  // emit("SECTION", ".data")
  //   for those entries in the symbolTable that have
  //     an allocation of YES and a storage mode of CONSTANT
  //   {call emit to output a line to objectFile}
  //     emit("SECTION", ".bss")
  //     for those entries in the symbolTable that have
  //       an allocation of YES and a storage mode of VARIABLE
  //     {call emit to output a line to objectFile}

  emit("SECTION", ".data");

  for (i = symbolTable.begin(); i != symbolTable.end(); i++)
  {
    if (i->second.getAlloc() == YES && i->second.getMode() == CONSTANT)
    {
      emit(i->second.getInternalName(), "dd", i->second.getValue(), "; " + i->first);
    }
  }

  objectFile << endl;
  emit("SECTION", ".bss");

  for (i = symbolTable.begin(); i != symbolTable.end(); i++)
  {
    if (i->second.getAlloc() == YES && i->second.getMode() == VARIABLE)
    {
      emit(i->second.getInternalName(), "resd", i->second.getValue(), "; " + i->first);
    }
  }
}

void Compiler::emitReadCode(string operand, string operand2)
{
  string name;
  for (uint i = 0; i < operand.size(); ++i)
  {

    if (operand[ i ] != ',' && i < operand.size())
    {
      name += operand[ i ];
      continue;
    }

    if (name != "")
    {
      if (symbolTable.count(name) == 0)
      {
        processError("reference to undefined symbol " + name);
      }
      if (symbolTable.at(name).getDataType() != INTEGER)
      {
        processError("can't read variables of this type");
      }
      if (symbolTable.at(name).getMode() != VARIABLE)
      {
        processError("attempting to read to a read-only location");
      }
      emit("", "call", "ReadInt", "; read int; value placed in eax");
      emit("", "mov", "[" + symbolTable.at(name).getInternalName() + "],eax", "; store eax at " + name);
      contentsOfAReg = symbolTable.at(name).getInternalName();
    }
    name = "";
  }

  if (name != "")
  {
    if (symbolTable.count(name) == 0)
    {
      processError("reference to undefined symbol " + name);
    }
    if (symbolTable.at(name).getDataType() != INTEGER)
    {
      processError("can't read variables of this type");
    }
    if (symbolTable.at(name).getMode() != VARIABLE)
    {
      processError("attempting to read to a read-only location");
    }
    emit("", "call", "ReadInt", "; read int; value placed in eax");
    emit("", "mov", "[" + symbolTable.at(name).getInternalName() + "],eax", "; store eax at " + name);
    contentsOfAReg = symbolTable.at(name).getInternalName();
  }
}


void Compiler::emitWriteCode(string operand, string operand2)
{
  string name;

  for (uint i = 0; i < operand.size(); ++i)
  {

    if (operand[ i ] != ',' && i < operand.size()) // get operand string and assign it to name
    {
      name += operand[ i ];
      continue;
    }
    if (name.length() > 15)
    {
      name = name.substr(0, 15);
    }

    if (name != "") // if name is not empty
    {
      if (symbolTable.count(name) == 0) // if name is not defined in symbolTable
      {
        processError("reference to undefined symbol " + name); // processError
      }
      if (symbolTable.at(name).getInternalName() != contentsOfAReg) // if name != AReg;
      {
        emit("", "mov", "eax,[" + symbolTable.at(name).getInternalName() + "]", "; load " + name + " in eax"); // emit "mov eax, [name]; load name in eax"
        contentsOfAReg = symbolTable.at(name).getInternalName(); // AReg = name
      }
      emit("", "call", "WriteInt", "; write int in eax to standard out"); // emit "call WriteInt; write int in eax to standard out"

      emit("", "call", "Crlf", "; write \\r\\n to standard out"); // emit "call Crlf; write \r\n to standard out"
    }
    name = ""; // deassign name
  }

  if (symbolTable.count(name) == 0) // if name is not defined in symbolTable
  {
    processError("reference to undefined symbol " + name);
  }
  if (symbolTable.at(name).getInternalName() != contentsOfAReg) // if name != AReg
  {
    emit("", "mov", "eax,[" + symbolTable.at(name).getInternalName() + "]", "; load " + name + " in eax"); // emit "mov eax,[name]; load name in eax"
    contentsOfAReg = symbolTable.at(name).getInternalName(); // AReg = name
  }
  emit("", "call", "WriteInt", "; write int in eax to standard out"); // emit "call WriteInt; write int in eax to standard out"

  emit("", "call", "Crlf", "; write \\r\\n to standard out"); // emit "call Crlf; write \r\n to standard out"
}

void Compiler::emitAssignCode(string operand1, string operand2) // operand2 = operand1
{
  if (symbolTable.count(operand1) == 0) // if operand1 is not defined in symbolTable
  {
    processError("reference to undefined symbol " + operand1);
  }

  else if (symbolTable.count(operand2) == 0) // if operand2 is not defined in symbolTable
  {
    processError("reference to undefined symbol " + operand2);
  }

  if (symbolTable.at(operand1).getDataType() != symbolTable.at(operand2).getDataType()) // if both operands datatype is not same
  {
    processError("incompatible types for operator ':='");
  }

  if (symbolTable.at(operand2).getMode() != VARIABLE) // if operand's mode is not variable
  {
    processError("symbol on left-hand side of assignment must have a storage mode of VARIABLE");
  }

  if (operand1 == operand2) // if both operands are same
  {
    return; // do nothing
  }

  if (contentsOfAReg != symbolTable.at(operand1).getInternalName()) // if AReg != operand1
  {
    emit("", "mov", "eax,[" + symbolTable.at(operand1).getInternalName() + "]", "; AReg = " + operand1); // emit "mov eax,[operand1]; AReg = operand1"
  }

  emit("", "mov", "[" + symbolTable.at(operand2).getInternalName() + "],eax", "; " + operand2 + " = AReg"); // emit "mov [operand2],eax; operand2 = AReg"

  contentsOfAReg = symbolTable.at(operand2).getInternalName(); // AReg = operand2

  if (isTemporary(operand1)) // if operand1 == "Tx"
  {
    freeTemp(); // currentTempNo--;
  }
}

void Compiler::emitAdditionCode(string operand1, string operand2) // operand2 + operand1
{
  if (symbolTable.find(operand1) == symbolTable.end()) // if operand1 is not defined in symbolTable
  {
    processError("reference to undefined symbol " + operand1);
  }
  else if (symbolTable.find(operand2) == symbolTable.end()) // if operand2 is not defined in symbolTable
  {
    processError("reference to undefined symbol " + operand2);
  }
  if (whichType(operand1) != INTEGER || whichType(operand2) != INTEGER) // if operand1 or operand2 are not INTEGERs
  {
    processError("binary '+' requires integer operands");
  }
  if (contentsOfAReg[ 0 ] == 'T' && contentsOfAReg != symbolTable.at(operand1).getInternalName() &&
      contentsOfAReg != symbolTable.at(operand2).getInternalName()) // if AReg == 'Tx' and AReg != operand1 and AReg != operand2
  {
    emit("", "mov", "[" + contentsOfAReg + "],eax", "; deassign AReg"); // emit "mov [AReg],eax; deassign AReg"
    symbolTable.at(contentsOfAReg).setAlloc(YES); // setAllocation of AReg
    contentsOfAReg = ""; // deassign AReg
  }

  if (!contentsOfAReg.empty() && contentsOfAReg[ 0 ] != 'T' &&  // if AReg is empty and AReg != 'Tx' and AReg != operand1 and AReg != operand2
      contentsOfAReg != symbolTable.at(operand1).getInternalName() &&
      contentsOfAReg != symbolTable.at(operand2).getInternalName())
  {
    contentsOfAReg = "";  // deassign AReg 
  }

  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && // if AReg != operand1 && AReg != operand2
      contentsOfAReg != symbolTable.at(operand2).getInternalName())
  {
    emit("", "mov", "eax,[" + symbolTable.at(operand2).getInternalName() + "]", "; AReg = " + operand2); // emit "mov eax,[operand2]; AReg = operand2"
    contentsOfAReg = symbolTable.at(operand2).getInternalName(); // AReg = operand2
  }

  if (contentsOfAReg == symbolTable.at(operand2).getInternalName()) // if AReg is operand2
  {
    emit("", "add", "eax,[" + symbolTable.at(operand1).getInternalName() + "]", // emit "add eax,[operand1]; AReg = operand2 + operand1"
         "; AReg = " + operand2 + " + " + operand1);
  }
  else
  {
    emit("", "add", "eax,[" + symbolTable.at(operand2).getInternalName() + "]", // emit "add eax,[operand2]; AReg = operand1 + operand2"
         "; AReg = " + operand1 + " + " + operand2);
  }

  if (isTemporary(operand1)) // if operand1 == "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  if (isTemporary(operand2)) // if operand2 == "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  contentsOfAReg = getTemp(); // AReg = "Tx" 
  symbolTable.at(contentsOfAReg).setDataType(INTEGER); // set type of AReg to INTEGER
  pushOperand(contentsOfAReg); // push AReg to Operand
}

void Compiler::emitSubtractionCode(string operand1, string operand2) // operand2 - operand1
{
  if (symbolTable.find(operand1) == symbolTable.end()) // if operand1 is not defined in symbolTable
  {
    processError("reference to undefined symbol " + operand1);
  }
  else if (symbolTable.find(operand2) == symbolTable.end()) // if operand2 is not defined in symbolTable
  {
    processError("reference to undefined symbol " + operand2);
  }
  if (whichType(operand1) != INTEGER || whichType(operand2) != INTEGER) // if both types are not INTEGERs
  {
    processError("binary '-' requires integer operands");
  }

  if (contentsOfAReg[ 0 ] == 'T' && contentsOfAReg != symbolTable.at(operand2).getInternalName())
  { // if AReg == 'Tx' and AReg != operand2
    emit("", "mov", "[" + contentsOfAReg + "],eax", "; deassign AReg"); // emit "mov [AReg],eax ;deassign AReg"
    symbolTable.at(contentsOfAReg).setAlloc(YES); // allocate AReg at symbolTable
    contentsOfAReg = ""; // deassign AReg
  }
  if (contentsOfAReg[ 0 ] != 'T' && !contentsOfAReg.empty() && // if AReg is not "Tx" and AReg is not empty and AReg != operand2
      contentsOfAReg != symbolTable.at(operand2).getInternalName())
  {
    contentsOfAReg = ""; // deassign AReg
  }
  if (contentsOfAReg != symbolTable.at(operand2).getInternalName()) // if AReg != operand2
  {
    emit("", "mov", "eax,[" + symbolTable.at(operand2).getInternalName() + "]", "; AReg = " + operand2);
    //emit "mov, eax[operand2]; AReg = operand2"
    contentsOfAReg = symbolTable.at(operand2).getInternalName(); // AReg = operand2;
  }

  if (contentsOfAReg == symbolTable.at(operand2).getInternalName()) // if AReg == operand2
  {
    // emit "sub eax,[operand1]; AReg = operand2 - operand1"
    emit("", "sub", "eax,[" + symbolTable.at(operand1).getInternalName() + "]",
         "; AReg = " + operand2 + " - " + operand1);
  }
  if (isTemporary(operand1)) // if operand1 == "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  if (isTemporary(operand2)) // if operand2 == "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  contentsOfAReg = getTemp(); // AReg = "Tx"
  symbolTable.at(contentsOfAReg).setDataType(INTEGER); // set AReg to INTEGER
  pushOperand(contentsOfAReg); // push AReg to Operand
}

void Compiler::emitNegationCode(string operand1, string operand2)
{
  if (symbolTable.find(operand1) == symbolTable.end()) // if operand1 is not defined in symbolTable
  {
    processError("reference to undefined symbol " + operand1);
  }

  if (whichType(operand1) != INTEGER) // if type of operand1 is not INTEGER
  {
    processError("binary '-' requires integer operands");
  }
  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && contentsOfAReg[ 0 ] == 'T')
  { // if AReg != operand1 and AReg == "Tx"
    emit("", "mov", "[" + contentsOfAReg + "],eax", "; deassign AReg"); // emit "mov [AReg],eax ; deassign AReg"
    symbolTable.at(contentsOfAReg).setAlloc(YES); // set Allocation AReg
    contentsOfAReg = ""; // deassign AReg
  }

  if (!contentsOfAReg.empty() && contentsOfAReg[ 0 ] != 'T' && // if AReg is empty and AReg == "Tx" and AReg != operand1
      contentsOfAReg != symbolTable.at(operand1).getInternalName())
  {
    contentsOfAReg = ""; // deassign AReg
  }
  if (contentsOfAReg != symbolTable.at(operand1).getInternalName()) // if AReg != operand1
  {
    // emit "mov eax,[operand1]; AReg = operand1"
    emit("", "mov", "eax,[" + symbolTable.at(operand1).getInternalName() + "]", "; AReg = " + operand1);
    contentsOfAReg = symbolTable.at(operand1).getInternalName(); // AReg = operand1
  }

  emit("", "neg", "eax", "; AReg = -AReg"); // emit "neg eax; AReg = AReg"
  if (isTemporary(operand1)) // if operand1 = "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  contentsOfAReg = getTemp(); // AReg = "Tx"
  symbolTable.at(contentsOfAReg).setDataType(INTEGER); // set AReg to INTEGER
  pushOperand(contentsOfAReg); // push AReg to Operand
}

void Compiler::emitNotCode(string operand1, string operand2) // !op1
{
  if (symbolTable.find(operand1) == symbolTable.end()) // if operand1 is not defined in symbolTable
  {
    processError("reference to undefined symbol " + operand1);
  }
  if (whichType(operand1) != BOOLEAN) // if type of operand1 is not BOOLEAN
  {
    processError("binary 'not' requires boolean operands");
  }
  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && contentsOfAReg[ 0 ] == 'T')
  {
    emit("", "mov", "[" + contentsOfAReg + "],eax", "; deassign AReg"); // emit "mov [AReg],eax ; deassign AReg"
    symbolTable.at(contentsOfAReg).setAlloc(YES); // generate "Tx" in symbolTable
    contentsOfAReg = ""; // deassign AReg
  }

  if (!contentsOfAReg.empty() && contentsOfAReg[ 0 ] != 'T' && // if Areg is not empty and AReg != "Tx" ad AReg != operand1
      contentsOfAReg != symbolTable.at(operand1).getInternalName())
  {
    contentsOfAReg = ""; // deassign AReg
  }
  if (contentsOfAReg != symbolTable.at(operand1).getInternalName()) // if AReg != operand1
  {
    // emit "mov eax,[operand1]; Areg operand1"
    emit("", "mov", "eax,[" + symbolTable.at(operand1).getInternalName() + "]", "; AReg = " + operand1);
    contentsOfAReg = symbolTable.at(operand1).getInternalName();
  }

  emit("", "not", "eax", "; AReg = !AReg"); // emit "not eax; AReg = !AReg"

  if (isTemporary(operand1)) // if operand1 == "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  contentsOfAReg = getTemp(); // Areg = "Tx"
  symbolTable.at(contentsOfAReg).setDataType(BOOLEAN); // set type of AReg to BOOLEAN
  pushOperand(contentsOfAReg); // push AReg to Operand
}

void Compiler::emitMultiplicationCode(string operand1, string operand2) // op2 * op1
{
  if (symbolTable.find(operand1) == symbolTable.end()) // if operand1 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand1);
  }
  else if (symbolTable.find(operand2) == symbolTable.end()) // if operand2 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand2);
  }

  if (whichType(operand1) != INTEGER || whichType(operand2) != INTEGER) // if both operand are not INTEGERs
  {
    processError("binary '*' requires integer operands");
  }
  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && // if AReg != operand1 and AReg != operand2 and AReg == "Tx"
      contentsOfAReg != symbolTable.at(operand2).getInternalName() && contentsOfAReg[ 0 ] == 'T')
  {
    emit("", "mov", "[" + contentsOfAReg + "],eax", "; deassign AReg"); // emit "mov [AReg], eax; deassign AReg"
    symbolTable.at(contentsOfAReg).setAlloc(YES); // generate "Tx" at symbolTable
    contentsOfAReg = ""; // deassign ARegg
  }

  if (!contentsOfAReg.empty() && contentsOfAReg[ 0 ] != 'T' && // if AReg is not empty and AReg != "Tx" and AReg != operand1 and AReg != operand2
      contentsOfAReg != symbolTable.at(operand1).getInternalName() &&
      contentsOfAReg != symbolTable.at(operand2).getInternalName())
  {
    contentsOfAReg = ""; // deassign AReg
  }
  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && // if AReg != operand1 and AReg != operand2
      contentsOfAReg != symbolTable.at(operand2).getInternalName())
  {
    //emit "mov eax,[operand2]; AReg operand2"
    emit("", "mov", "eax,[" + symbolTable.at(operand2).getInternalName() + "]", "; AReg = " + operand2);
    contentsOfAReg = symbolTable.at(operand2).getInternalName(); // AReg = operand2
  }

  if (contentsOfAReg == symbolTable.at(operand2).getInternalName()) // if AReg == operand2
  {
    emit("", "imul", "dword [" + symbolTable.at(operand1).getInternalName() + "]", // emit imul dword [operand1]; AReg = operand2 * operand1
         "; AReg = " + operand2 + " * " + operand1);
  }
  else
  {
    emit("", "imul", "dword [" + symbolTable.at(operand2).getInternalName() + "]", // emit imul dword [operand2]; AReg = operand1 * operand2
         "; AReg = " + operand1 + " * " + operand2);
  }

  if (isTemporary(operand1)) // if operand1 == "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  if (isTemporary(operand2)) // if operand2 == "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  contentsOfAReg = getTemp(); // AReg = "Tx"
  symbolTable.at(contentsOfAReg).setDataType(INTEGER); // set AReg to INTEGER
  pushOperand(contentsOfAReg); // push AReg to Operand
}

void Compiler::emitDivisionCode(string operand1, string operand2) // op2 / op1
{
  if (symbolTable.find(operand1) == symbolTable.end()) // if operand1 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand1);
  }
  else if (symbolTable.find(operand2) == symbolTable.end()) // if operand2 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand2);
  }
  if (whichType(operand1) != INTEGER || whichType(operand2) != INTEGER) // if both operands are not INTEGERs
  {
    processError("binary 'div' requires integer operands");
  }
  if (contentsOfAReg != "" && contentsOfAReg[ 0 ] == 'T' && contentsOfAReg != symbolTable.at(operand2).getInternalName())
  { // if AReg is not empty and AReg is "Tx" and AReg != operand2 
    emit("", "mov", "[" + contentsOfAReg + "],eax", "; deassign AReg"); // emit "mov [Areg],eax; deassign AReg"
    symbolTable.at(contentsOfAReg).setAlloc(YES); // generate AReg at symbolTable
    contentsOfAReg = ""; // deassign AReg
  }

  if (!contentsOfAReg.empty() && contentsOfAReg[ 0 ] != 'T' && // if AReg is not empty and AReg != "Tx" and AReg != operand2
      contentsOfAReg != symbolTable.at(operand2).getInternalName())
  {
    contentsOfAReg = ""; // deassign AReg 
  }
  if (contentsOfAReg != symbolTable.at(operand2).getInternalName()) // if AReg is not operand2
  {
    // emit "mov eax,[operand2]; AReg = operand2"
    emit("", "mov", "eax,[" + symbolTable.at(operand2).getInternalName() + "]", "; AReg = " + operand2);
    contentsOfAReg = symbolTable.at(operand2).getInternalName(); // AReg = operand2
  }
  emit("", "cdq", "", "; sign extend dividend from eax to edx:eax"); // emit "cdq; sign extended from eax to edx:eax"
  emit("", "idiv", "dword [" + symbolTable.at(operand1).getInternalName() + "]",
       "; AReg = " + operand2 + " div " + operand1); // emit "idiv dword [operand1]; AReg = operand2 div operand1"

  if (isTemporary(operand1)) // if operand1 = "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  if (isTemporary(operand2)) // if operand1 = "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  contentsOfAReg = getTemp(); // AReg = "Tx"
  symbolTable.at(contentsOfAReg).setDataType(INTEGER); // set AReg to INTEGER
  pushOperand(contentsOfAReg); // push AReg to Operand
}

void Compiler::emitModuloCode(string operand1, string operand2)
{ // op2 %  op1 
  if (symbolTable.find(operand1) == symbolTable.end()) // if operand1 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand1);
  }
  else if (symbolTable.find(operand2) == symbolTable.end()) // if operand2 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand2);
  }
  if (whichType(operand1) != INTEGER || whichType(operand2) != INTEGER) // if both operand are not INTEGERs
  {
    processError("binary 'mod' requires integer operands");
  }

  if (contentsOfAReg[ 0 ] == 'T' && contentsOfAReg != symbolTable.at(operand2).getInternalName())
  { // if AReg == "Tx" and AReg != operand2
    emit("", "mov", "[" + contentsOfAReg + "],eax", "; deassign AReg"); // emit "mov [AReg],eax ; deassign AReg"
    symbolTable.at(contentsOfAReg).setAlloc(YES); // generate AReg at symbolTable
    contentsOfAReg = ""; // deassign AReg
  }

  if (!contentsOfAReg.empty() && contentsOfAReg[ 0 ] != 'T' && // if AReg is empty and AReg != "Tx" and AReg != operand2
      contentsOfAReg != symbolTable.at(operand2).getInternalName())
  {
    contentsOfAReg = ""; // deassign AReg
  }
  if (contentsOfAReg != symbolTable.at(operand2).getInternalName()) // if AReg != operand2
  {
    // emit "mov eax,[operand2]; AReg = operand2"
    emit("", "mov", "eax,[" + symbolTable.at(operand2).getInternalName() + "]", "; AReg = " + operand2);
    contentsOfAReg = symbolTable.at(operand2).getInternalName(); // AReg = operand2
  }

  emit("", "cdq", "", "; sign extend dividend from eax to edx:eax"); // emit "cdq; sign extended dividened from eax to edx:eax"
  emit("", "idiv", "dword [" + symbolTable.at(operand1).getInternalName() + "]", // emit "idiv dword [operand1]; AReg = op2 div op1"
       "; AReg = " + operand2 + " div " + operand1);
  emit("", "xchg", "eax,edx", "; exchange quotient and remainder"); // emit "xchg eax,edx; exchange quotient and remainder"

  if (isTemporary(operand1)) // if operand1 == "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  if (isTemporary(operand2))// if operand2 == "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  contentsOfAReg = getTemp(); // AReg = "Tx"
  symbolTable.at(contentsOfAReg).setDataType(INTEGER); // set AReg to INTEGER
  pushOperand(contentsOfAReg); // push AReg to Operand
}

void Compiler::emitAndCode(string operand1, string operand2) // op2 && op1
{
  if (symbolTable.find(operand1) == symbolTable.end()) // if operand1 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand1);
  }
  else if (symbolTable.find(operand2) == symbolTable.end()) // if operand2 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand2);
  }

  if (whichType(operand1) != BOOLEAN || whichType(operand2) != BOOLEAN) // if one of both opernads is not BOOLEAN
  {
    processError("binary 'and' requires boolean operands");
  }

  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && // if AReg != operand1 and AReg != operand2 and AReg == "Tx"
      contentsOfAReg != symbolTable.at(operand2).getInternalName() && contentsOfAReg[ 0 ] == 'T')
  {
    emit("", "mov", "[" + contentsOfAReg + "],eax", "; deassign AReg"); // emit "mov [AReg],eax; deassign AReg"
    symbolTable.at(contentsOfAReg).setAlloc(YES); // generate Areg at symbolTable
    contentsOfAReg = ""; // deassign AReg
  }

  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && // if AReg != operand1 and AReg != operand2 and AReg is not empty 
      contentsOfAReg != symbolTable.at(operand2).getInternalName() && !contentsOfAReg.empty() &&
      contentsOfAReg[ 0 ] != 'T') // and AReg is not "Tx"
  {
    contentsOfAReg = ""; // deassign AReg
  }
  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && // if AReg != operand1 and AReg != operand2
      contentsOfAReg != symbolTable.at(operand2).getInternalName())
  { // emit "mov eax,[operand2] ; AReg = operand2"
    emit("", "mov", "eax,[" + symbolTable.at(operand2).getInternalName() + "]", "; AReg = " + operand2);
    contentsOfAReg = symbolTable.at(operand2).getInternalName(); // AReg = operand2 
  }

  if (contentsOfAReg == symbolTable.at(operand2).getInternalName()) // if AReg = operand2
  {
    emit("", "and", "eax,[" + symbolTable.at(operand1).getInternalName() + "]", // emit "and eax,[operand1]; AReg = operand2 and operand1"
         "; AReg = " + operand2 + " and " + operand1);
  }
  else
  {
    emit("", "and", "eax,[" + symbolTable.at(operand2).getInternalName() + "]", // emit "and eax,[operand2]; AReg = operand1 and operand2"
         "; AReg = " + operand1 + " and " + operand2);
  }
  if (isTemporary(operand1)) // if operand1 == "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  if (isTemporary(operand2)) // if operand2 == "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  contentsOfAReg = getTemp(); // AReg = "Tx"
  symbolTable.at(contentsOfAReg).setDataType(BOOLEAN); // set AReg to BOOLEAN
  pushOperand(contentsOfAReg); // push AReg to Operand
}

void Compiler::emitOrCode(string operand1, string operand2) // op2 || op1
{
  if (symbolTable.find(operand1) == symbolTable.end()) // if operand1 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand1);
  }
  else if (symbolTable.find(operand2) == symbolTable.end()) // if operand2 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand2);
  }

  if (whichType(operand1) != BOOLEAN || whichType(operand2) != BOOLEAN)  // if one of both opernads is not BOOLEAN
  {
    processError("binary 'or' requires boolean operands");
  }
  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && // if AReg != operand1 and AReg != operand2 and AReg == "Tx"
      contentsOfAReg != symbolTable.at(operand2).getInternalName() && contentsOfAReg[ 0 ] == 'T')
  {
    emit("", "mov", "[" + contentsOfAReg + "],eax", "; deassign AReg"); // emit "mov [AReg],eax; deassign AReg"
    symbolTable.at(contentsOfAReg).setAlloc(YES); // generate AReg at symbolTable
    contentsOfAReg = ""; // deassign AReg
  }

  if (!contentsOfAReg.empty() && contentsOfAReg[ 0 ] != 'T' && // if AReg != operand1 and AReg != operand2 and AReg is not empty and AReg = "Tx"
      contentsOfAReg != symbolTable.at(operand1).getInternalName() &&
      contentsOfAReg != symbolTable.at(operand2).getInternalName())
  {
    contentsOfAReg = ""; // deassign AReg
  }
  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && // if AReg != operand1 and AReg != operand2
      contentsOfAReg != symbolTable.at(operand2).getInternalName())
  {
    emit("", "mov", "eax,[" + symbolTable.at(operand2).getInternalName() + "]", "; AReg = " + operand2); // emit "mov eax,[operand2]; AReg = operand2"
    contentsOfAReg = symbolTable.at(operand2).getInternalName(); // AReg = operand2
  }

  if (contentsOfAReg == symbolTable.at(operand2).getInternalName()) // if AReg == operand2
  {
    emit("", "or", "eax,[" + symbolTable.at(operand1).getInternalName() + "]", // emit "or eax,[operand1]; AReg = operand2 or operand1"
         "; AReg = " + operand2 + " or " + operand1);
  }
  else
  {
    emit("", "or", "eax,[" + symbolTable.at(operand2).getInternalName() + "]", // emit "or eax,[operand2]; AReg = operand1 or operand2"
         "; AReg = " + operand1 + " or " + operand2);
  }

  if (isTemporary(operand1)) // if operand1 == "Tx"
  {
    freeTemp(); //currentTempNo--
  }
  if (isTemporary(operand2)) // if operand2 == "Tx"
  {
    freeTemp(); //currentTempNo--
  }
  contentsOfAReg = getTemp(); // AReg = "Tx"
  symbolTable.at(contentsOfAReg).setDataType(BOOLEAN); // set AReg to BOOLEAN
  pushOperand(contentsOfAReg); // push AReg to Operand
}

void Compiler::emitEqualityCode(string operand1, string operand2) // op2 == op1
{
  if (symbolTable.find(operand1) == symbolTable.end()) // if operand1 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand1);
  }
  else if (symbolTable.find(operand2) == symbolTable.end()) // if operand2 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand2);
  }
  if (whichType(operand1) != whichType(operand2))  // if one of both opernads is not BOOLEAN
  {
    processError("incompatible types for operator '='");
  }

  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && // if AReg != operand1 and AReg != operand2 and AReg = "Tx"
      contentsOfAReg != symbolTable.at(operand2).getInternalName() && contentsOfAReg[ 0 ] == 'T')
  {
    emit("", "mov", "[" + contentsOfAReg + "],eax", "; deassign AReg"); // emit "mov [AReg],eax; deassign AReg"
    symbolTable.at(contentsOfAReg).setAlloc(YES); // generate AReg at symbolTable
    contentsOfAReg = ""; // deaassign AReg
  }

  if (!contentsOfAReg.empty() && contentsOfAReg[ 0 ] != 'T' && // if AReg is empty and AReg != "Tx" and AReg != op1 and AReg != op2
      contentsOfAReg != symbolTable.at(operand1).getInternalName() &&
      contentsOfAReg != symbolTable.at(operand2).getInternalName())
  {
    contentsOfAReg = ""; // deassign AReg
  }
  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && // if AReg != operand1 and AReg != operand2
      contentsOfAReg != symbolTable.at(operand2).getInternalName())
  {
    // emit "mov eax,[operand2]; AReg = operand2"
    emit("", "mov", "eax,[" + symbolTable.at(operand2).getInternalName() + "]", "; AReg = " + operand2);
    contentsOfAReg = symbolTable.at(operand2).getInternalName(); // AReg = operand2
  }

  if (contentsOfAReg == symbolTable.at(operand2).getInternalName()) // if AReg == operand2
  {
    emit("", "cmp", "eax,[" + symbolTable.at(operand1).getInternalName() + "]",
         "; compare " + operand2 + " and " + operand1); // emit "cmp eax,[op1]; compare op2 and op1"
  }
  else
  {
    emit("", "cmp", "eax,[" + symbolTable.at(operand2).getInternalName() + "]",
         "; compare " + operand1 + " and " + operand2); // emit "cmp eax,[op2]; compare op1 and op2"
  }
  string firstLab = getLabel(), secLab = getLabel();
  // firstLab = L0
  // SecLab   = L1

  emit("", "je", "." + firstLab, "; if " + operand2 + " = " + operand1 + " then jump to set eax to TRUE");
  emit("", "mov", "eax,[FALSE]", "; else set eax to FALSE");

  if (symbolTable.count("false") == 0) // if false is not defined
  {
    insert("false", BOOLEAN, CONSTANT, "0", YES, 1); // insert false at .data SECTION
    symbolTable.at("false").setInternalName("FALSE"); // then change false to FALSE
  }
  emit("", "jmp", "." + secLab, "; unconditionally jump"); // emit "jmp. L1 unconditionally jump"
  emit("." + firstLab + ":"); // emit " .L0: "
  emit("", "mov", "eax,[TRUE]", "; set eax to TRUE"); // emit "mov eax,[TRUE]; set eax to TRUE"

  if (symbolTable.count("true") == 0) // if true is not defined
  {
    insert("true", BOOLEAN, CONSTANT, "-1", YES, 1);  // insert true at .data SECTION
    symbolTable.at("true").setInternalName("TRUE"); // then change true to TRUE
  }
  emit("." + secLab + ":"); // emit ". L1: "

  if (isTemporary(operand1)) // if operand1 = "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  if (isTemporary(operand2)) // if operand1 = "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  contentsOfAReg = getTemp(); // AReg = "Tx"
  symbolTable.at(contentsOfAReg).setDataType(BOOLEAN); // set datatype of AReg to BOOLEAN
  pushOperand(contentsOfAReg); // push AReg to Operand
}

void Compiler::emitInequalityCode(string operand1, string operand2) // op2 != op1
{
  if (symbolTable.find(operand1) == symbolTable.end()) // if operand1 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand1);
  }
  else if (symbolTable.find(operand2) == symbolTable.end()) // if operand2 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand2);
  }
  if (whichType(operand1) != whichType(operand2)) // if both types are not matched
  {
    processError("incompatible types for operator '<>'");
  }
  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && // if AReg != op1 and AReg != op2 and Areg = "Tx"
      contentsOfAReg != symbolTable.at(operand2).getInternalName() && contentsOfAReg[ 0 ] == 'T')
  {
    emit("", "mov", "[" + contentsOfAReg + "],eax", "; deassign AReg"); // emit "mov [AReg],eax ; deassign AReg"
    symbolTable.at(contentsOfAReg).setAlloc(YES); // generate AReg at symbolTable
    contentsOfAReg = ""; // deassign AReg 
  }

  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && // if AReg != op1 and AReg != op2 and AReg is not empty
      contentsOfAReg != symbolTable.at(operand2).getInternalName() && !contentsOfAReg.empty() &&
      contentsOfAReg[ 0 ] != 'T') // and AReg != "Tx"
  {
    contentsOfAReg = ""; // deassign AReg
  }
  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && // if AReg != op1 and AReg != op2
      contentsOfAReg != symbolTable.at(operand2).getInternalName())
  { // emit "mov eax,[operand2]; AReg = operand2"
    emit("", "mov", "eax,[" + symbolTable.at(operand2).getInternalName() + "]", "; AReg = " + operand2);
    contentsOfAReg = symbolTable.at(operand2).getInternalName(); // AReg = operand2
  }

  if (contentsOfAReg == symbolTable.at(operand2).getInternalName()) // if AReg == op2
  {
    emit("", "cmp", "eax,[" + symbolTable.at(operand1).getInternalName() + "]",
         "; compare " + operand2 + " and " + operand1); // emit "cmp eax,[operand1]; compare op1 and op2"
  }
  else
  {
    emit("", "cmp", "eax,[" + symbolTable.at(operand2).getInternalName() + "]",
         "; compare " + operand1 + " and " + operand2); // emit "cmp eax,[operand2]; compare op2 and op1"
  }

  string firstLab = getLabel(), secLab = getLabel();
  // firstLab = L0
  // SecLab   = L1
  emit("", "jne", "." + firstLab, "; if " + operand2 + " <> " + operand1 + " then jump to set eax to TRUE");
  emit("", "mov", "eax,[FALSE]", "; else set eax to FALSE"); // emit "mov eax,[FALSE]; else set eax to FALSE"

  if (symbolTable.count("false") == 0) // if false is not defined
  {
    insert("false", BOOLEAN, CONSTANT, "0", YES, 1); // insert false at .data SECTION
    symbolTable.at("false").setInternalName("FALSE"); // then change false to FALSE
  }
  emit("", "jmp", "." + secLab, "; unconditionally jump"); // emit "jmp. L1 unconditionally jump"
  emit("." + firstLab + ":"); // emit " .L0: "
  emit("", "mov", "eax,[TRUE]", "; set eax to TRUE"); // emit "mov eax,[TRUE]; set eax to TRUE"

  if (symbolTable.count("true") == 0) // if true is not defined
  {
    insert("true", BOOLEAN, CONSTANT, "-1", YES, 1); // insert true at .data SECTION
    symbolTable.at("true").setInternalName("TRUE"); // then change true to TRUE
  }
  emit("." + secLab + ":"); // emit ".L1: "

  if (isTemporary(operand1)) // if operand1 = "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  if (isTemporary(operand2)) // if operand1 = "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  contentsOfAReg = getTemp(); // AReg = "Tx"
  symbolTable.at(contentsOfAReg).setDataType(BOOLEAN); // set datatype of AReg to BOOLEAN
  pushOperand(contentsOfAReg); // push AReg to Operand
}

void Compiler::emitLessThanCode(string operand1, string operand2) // op2 < op1
{
  if (symbolTable.find(operand1) == symbolTable.end()) // if operand1 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand1);
  }
  else if (symbolTable.find(operand2) == symbolTable.end()) // if operand2 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand2);
  }

  if (whichType(operand1) != whichType(operand2)) // if both types are not matched
  {
    processError("incompatible types for operator '<'");
  }
  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && // if AReg != op1 and AReg != op2 and Areg = "Tx"
      contentsOfAReg != symbolTable.at(operand2).getInternalName() && contentsOfAReg[ 0 ] == 'T')
  {
    emit("", "mov", "[" + contentsOfAReg + "],eax", "; deassign AReg"); // emit "mov [AReg],eax ; deassign AReg"
    symbolTable.at(contentsOfAReg).setAlloc(YES); // generate AReg at symbolTable
    contentsOfAReg = ""; // deassign AReg
  }

  if (!contentsOfAReg.empty() && contentsOfAReg[ 0 ] != 'T' && // if AReg is empty and AReg = "Tx" and AReg != op1 and AReg != op2
      contentsOfAReg != symbolTable.at(operand1).getInternalName() &&
      contentsOfAReg != symbolTable.at(operand2).getInternalName())
  {
    contentsOfAReg = ""; // deassign AReg
  }
  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && // if AReg != op1 and AReg != op2
      contentsOfAReg != symbolTable.at(operand2).getInternalName())
  {
    // emit "mov eax,[operand2]; AReg = operand2"
    emit("", "mov", "eax,[" + symbolTable.at(operand2).getInternalName() + "]", "; AReg = " + operand2);
    contentsOfAReg = symbolTable.at(operand2).getInternalName(); // AReg = operand2
  }

  if (contentsOfAReg == symbolTable.at(operand2).getInternalName()) // if AReg == operand2
  {
    emit("", "cmp", "eax,[" + symbolTable.at(operand1).getInternalName() + "]",
         "; compare " + operand2 + " and " + operand1); // emit "cmp eax,[operand1]; compare op2 and op1"
  }
  else
  {
    emit("", "cmp", "eax,[" + symbolTable.at(operand2).getInternalName() + "]",
         "; compare " + operand1 + " and " + operand2); // emit "cmp eax,[operand2]; compare op1 and op2"
  }
  string firstLab = getLabel(), secLab = getLabel();
  // firstLab = L0
  // SecLab   = L1
  if (contentsOfAReg == symbolTable.at(operand2).getInternalName()) // if AReg == operand2
  {
    // emit "jl. L0; if op2 < op1 then jump to set eax to TRUE"
    emit("", "jl", "." + firstLab, "; if " + operand2 + " < " + operand1 + " then jump to set eax to TRUE");
  }
  else
  {
    // emit "jl. L0; if op1 < op2 then jump to set eax to TRUE"
    emit("", "jl", "." + firstLab, "; if " + operand1 + " < " + operand2 + " then jump to set eax to TRUE");
  }
  // emit "mov eax,[FALSE]; else set eax to FALSE"
  emit("", "mov", "eax,[FALSE]", "; else set eax to FALSE");

  if (symbolTable.count("false") == 0) // if false is not defined in symbolTable
  {
    insert("false", BOOLEAN, CONSTANT, "0", YES, 1); // insert false at .data SECTION
    symbolTable.at("false").setInternalName("FALSE"); //then change false to FALSE
  }
  emit("", "jmp", "." + secLab, "; unconditionally jump"); // emit "jmp. L1 unconditionally jump"
  emit("." + firstLab + ":"); // emit " .L0: "
  emit("", "mov", "eax,[TRUE]", "; set eax to TRUE"); // emit "mov eax,[TRUE]; set eax to TRUE"

  if (symbolTable.count("true") == 0) // if true is not defined in symbolTable
  {
    insert("true", BOOLEAN, CONSTANT, "-1", YES, 1); // insert true at .data SECTION
    symbolTable.at("true").setInternalName("TRUE"); // change true to TRUE
  }
  emit("." + secLab + ":"); // emit ".L1: "

  if (isTemporary(operand1)) // if operand1 = "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  if (isTemporary(operand2)) // if operand1 = "Tx"
  {
    freeTemp(); // currentTempNo-- 
  }
  contentsOfAReg = getTemp(); // AReg = "Tx"
  symbolTable.at(contentsOfAReg).setDataType(BOOLEAN); // set datatype of AReg to BOOLEAN
  pushOperand(contentsOfAReg); // push AReg to Operand
}

void Compiler::emitLessThanOrEqualToCode(string operand1, string operand2) // op2 <= op1
{
  if (symbolTable.find(operand1) == symbolTable.end()) // if operand1 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand1);
  }
  else if (symbolTable.find(operand2) == symbolTable.end()) // if operand2 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand2);
  }
  if (whichType(operand1) != whichType(operand2)) // if both types are not matched
  {
    processError("incompatible types for operator '<='");
  }
  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && // if AReg != op1 and AReg != op2 and AReg == "Tx"
      contentsOfAReg != symbolTable.at(operand2).getInternalName() && contentsOfAReg[ 0 ] == 'T')
  {
    emit("", "mov", "[" + contentsOfAReg + "],eax", "; deassign AReg"); // emit "mov [Areg],eax ; deassign AReg"
    symbolTable.at(contentsOfAReg).setAlloc(YES); // insert AReg to symbolTable
    contentsOfAReg = ""; // deassign AReg
  }

  if (!contentsOfAReg.empty() && contentsOfAReg[ 0 ] != 'T' && // if AReg is empty and AReg != "Tx" and AReg != op1 and AReg != op2
      contentsOfAReg != symbolTable.at(operand1).getInternalName() &&
      contentsOfAReg != symbolTable.at(operand2).getInternalName())
  {
    contentsOfAReg = ""; // deassign AReg
  }
  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && // if AReg != op1 and AReg != op2
      contentsOfAReg != symbolTable.at(operand2).getInternalName())
  {
    // emit "mov eax,[operand2]; AReg = operand2"
    emit("", "mov", "eax,[" + symbolTable.at(operand2).getInternalName() + "]", "; AReg = " + operand2);
    contentsOfAReg = symbolTable.at(operand2).getInternalName(); // AReg = operand2
  }

  if (contentsOfAReg == symbolTable.at(operand2).getInternalName()) // if AReg == operand2
  {
    // emit "cmp eax,[operand1]; compare op2 and op1"
    emit("", "cmp", "eax,[" + symbolTable.at(operand1).getInternalName() + "]",
         "; compare " + operand2 + " and " + operand1);
  }
  else
  {
    // emit "cmp eax,[operand2]; compare op1 and op2"
    emit("", "cmp", "eax,[" + symbolTable.at(operand2).getInternalName() + "]",
         "; compare " + operand1 + " and " + operand2);
  }
  string firstLab = getLabel(), secLab = getLabel();
  // firstLab = L0
  // SecLab   = L1
  if (contentsOfAReg == symbolTable.at(operand2).getInternalName()) // if AReg == operand2
  {
    // emit "jle. L0; if op2 <= op1 then jump to set eax to TRUE"
    emit("", "jle", "." + firstLab, "; if " + operand2 + " <= " + operand1 + " then jump to set eax to TRUE");
  }
  else
  {
    // emit "jle. L0; if op1 <= op2 then jump to set eax to TRUE"
    emit("", "jle", "." + firstLab, "; if " + operand1 + " <= " + operand2 + " then jump to set eax to TRUE");
  }
  // emit "mov eax,[FALSE]; else set eax to FALSE"
  emit("", "mov", "eax,[FALSE]", "; else set eax to FALSE");

  if (symbolTable.count("false") == 0) // if false is not defined at data section
  {
    insert("false", BOOLEAN, CONSTANT, "0", YES, 1);  // insert false at .data SECTION
    symbolTable.at("false").setInternalName("FALSE"); // then change false to FALSE
  }
  emit("", "jmp", "." + secLab, "; unconditionally jump"); // emit "jmp. L1; unconditionally jump"
  emit("." + firstLab + ":"); // emit ".L0: "
  emit("", "mov", "eax,[TRUE]", "; set eax to TRUE"); // emit "mov eax,[TRUE]; set eax to TRUE"

  if (symbolTable.count("true") == 0) // if true is not defined at data section
  {
    insert("true", BOOLEAN, CONSTANT, "-1", YES, 1); // insert true at .data SECTION
    symbolTable.at("true").setInternalName("TRUE"); // then change true to TRUE
  }
  emit("." + secLab + ":"); // emit ".L1: "

  if (isTemporary(operand1)) // if operand1 = "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  if (isTemporary(operand2)) // // if operand2 = "Tx"
  {
    freeTemp(); // currentTempNo-- 
  }

  contentsOfAReg = getTemp(); // AReg = "Tx"
  symbolTable.at(contentsOfAReg).setDataType(BOOLEAN); // set datatype of AReg to BOOLEAN
  pushOperand(contentsOfAReg); // push AReg to Operand
}

void Compiler::emitGreaterThanCode(string operand1, string operand2) // op2 > op1
{

  if (symbolTable.find(operand1) == symbolTable.end()) // if operand1 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand1);
  }
  else if (symbolTable.find(operand2) == symbolTable.end()) // if operand2 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand2);
  }
  if (whichType(operand1) != whichType(operand2)) // if both types don't match
  {
    processError("incompatible types for operator '>'");
  }
  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() // if AReg != operand1 and AReg != operand2
    && contentsOfAReg != symbolTable.at(operand2).getInternalName()
      && contentsOfAReg[ 0 ] == 'T') // and AReg = "Tx"
  {
    emit("", "mov", "[" + contentsOfAReg + "],eax", "; deassign AReg"); // emit "mov [AReg],eax ; deassign AReg"
    symbolTable.at(contentsOfAReg).setAlloc(YES); // set allocation AReg at symbolTable
    contentsOfAReg = ""; // deassign AReg
  }

  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() // if AReg != operand1 and AReg != operand2
    && contentsOfAReg != symbolTable.at(operand2).getInternalName()
      && !contentsOfAReg.empty() && contentsOfAReg[ 0 ] != 'T')
  {
    contentsOfAReg = ""; // deassign AReg
  }
  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() // if AReg != operand1 and AReg != operand2
    && contentsOfAReg != symbolTable.at(operand2).getInternalName())
  {
    // emit "mov eax,[operand2]; AReg = operand2"
    emit("", "mov", "eax,[" + symbolTable.at(operand2).getInternalName() + "]", "; AReg = " + operand2);
    contentsOfAReg = symbolTable.at(operand2).getInternalName(); // AReg = operand2
  }

  if (contentsOfAReg == symbolTable.at(operand2).getInternalName())
  {
    // emit "cmp eax,[operand1]; compare op2 and op1"
    emit("", "cmp", "eax,[" + symbolTable.at(operand1).getInternalName() + "]", "; compare " + operand2 + " and " + operand1);
  }
  else
  {
    // emit "cmp eax,[operand2]; comapre op1 and op2"
    emit("", "cmp", "eax,[" + symbolTable.at(operand2).getInternalName() + "]", "; compare " + operand1 + " and " + operand2);
  }
  string firstLab = getLabel(), secLab = getLabel();
  // firstLab = L0
  // SecLab   = L1
  if (contentsOfAReg == symbolTable.at(operand2).getInternalName()) // if AReg == operand2
  {
    //emit "jg.L0; if op2 > op1 then jump to set eax to TRUE"
    emit("", "jg", "." + firstLab, "; if " + operand2 + " > " + operand1 + " then jump to set eax to TRUE");
  }
  else
  {
    //emit "jg.L0; if op1 > op2 then jump to set eax to TRUE"
    emit("", "jg", "." + firstLab, "; if " + operand1 + " > " + operand2 + " then jump to set eax to TRUE");
  }
  // emit "mov eax,[FALSE]; else set eax to FALSE"
  emit("", "mov", "eax,[FALSE]", "; else set eax to FALSE");

  if (symbolTable.count("false") == 0) // if false is not defined at data section
  {
    insert("false", BOOLEAN, CONSTANT, "0", YES, 1);  // insert false at .data SECTION
    symbolTable.at("false").setInternalName("FALSE"); // then change false to FALSE
  }
  emit("", "jmp", "." + secLab, "; unconditionally jump"); // emit "jmp. L1; unconditionally jump"
  emit("." + firstLab + ":"); // emit ".L0: "
  emit("", "mov", "eax,[TRUE]", "; set eax to TRUE"); // emit "mov eax,[TRUE]; set eax to TRUE"

  if (symbolTable.count("true") == 0) // if true is not defined at data section
  {
    insert("true", BOOLEAN, CONSTANT, "-1", YES, 1); // insert true at .data SECTION
    symbolTable.at("true").setInternalName("TRUE"); // then change true to TRUE
  }
  emit("." + secLab + ":"); // emit ".L1: "

  if (isTemporary(operand1)) // if operand1 = "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  if (isTemporary(operand2)) // // if operand2 = "Tx"
  {
    freeTemp(); // currentTempNo-- 
  }

  contentsOfAReg = getTemp(); // AReg = "Tx"
  symbolTable.at(contentsOfAReg).setDataType(BOOLEAN); // set datatype of AReg to BOOLEAN
  pushOperand(contentsOfAReg); // push AReg to Operand
}

void Compiler::emitGreaterThanOrEqualToCode(string operand1, string operand2) // op2 >= op1
{
  if (symbolTable.find(operand1) == symbolTable.end()) // if operand1 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand1);
  }
  else if (symbolTable.find(operand2) == symbolTable.end()) // if operand2 is not defined in SymbolTable
  {
    processError("reference to undefined symbol " + operand2);
  }
  if (whichType(operand1) != whichType(operand2)) // if both types are not matched
  {
    processError("incompatible types for operator '>='");
  }

  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && // if AReg != operand1 and AReg != operand2
      contentsOfAReg != symbolTable.at(operand2).getInternalName() && contentsOfAReg[ 0 ] == 'T') // and AReg = "Tx"
  {
    emit("", "mov", "[" + contentsOfAReg + "],eax", "; deassign AReg");
    symbolTable.at(contentsOfAReg).setAlloc(YES);
    contentsOfAReg = ""; // deassign AReg 
  }

  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && // if AReg != operand1 and AReg != operand2 and AReg is not empty
      contentsOfAReg != symbolTable.at(operand2).getInternalName() && !contentsOfAReg.empty() &&
      contentsOfAReg[ 0 ] != 'T')
  {
    contentsOfAReg = ""; // deassign AReg 
  }
  if (contentsOfAReg != symbolTable.at(operand1).getInternalName() && // if AReg != operand1 and AReg != operand2
      contentsOfAReg != symbolTable.at(operand2).getInternalName())
  {
    //emit "mov eax,[operand2]; AReg = operand2"
    emit("", "mov", "eax,[" + symbolTable.at(operand2).getInternalName() + "]", "; AReg = " + operand2);
    contentsOfAReg = symbolTable.at(operand2).getInternalName();
  }

  if (contentsOfAReg == symbolTable.at(operand2).getInternalName()) // if AReg == operand2
  {
    // emit "cmp eax,[operand1]; compare operand2 and oeprand1 "
    emit("", "cmp", "eax,[" + symbolTable.at(operand1).getInternalName() + "]",
         "; compare " + operand2 + " and " + operand1);
  }
  else
  {
    // emit "cmp eax,[operand2]; compare operand1 and oeprand2 "
    emit("", "cmp", "eax,[" + symbolTable.at(operand2).getInternalName() + "]",
         "; compare " + operand1 + " and " + operand2);
  }
  string firstLab = getLabel(), secLab = getLabel();
  // firstLab = L0
  // SecLab   = L1
  if (contentsOfAReg == symbolTable.at(operand2).getInternalName()) // if AReg == op2
  {
    // emit "jge .L0; if op2 >= op1 then jump to set eax to TRUE"
    emit("", "jge", "." + firstLab, "; if " + operand2 + " >= " + operand1 + " then jump to set eax to TRUE");
  }
  else
  {
    // emit "jge .L0; if op1 >= op2 then jump to set eax to TRUE"
    emit("", "jge", "." + firstLab, "; if " + operand1 + " >= " + operand2 + " then jump to set eax to TRUE");
  }
  // emit "mov eax,[FALSE]; else set eax to FALSE"
  emit("", "mov", "eax,[FALSE]", "; else set eax to FALSE");

  if (symbolTable.count("false") == 0) // if false is not defined at data section
  {
    insert("false", BOOLEAN, CONSTANT, "0", YES, 1);  // insert false at .data SECTION
    symbolTable.at("false").setInternalName("FALSE"); // then change false to FALSE
  }
  emit("", "jmp", "." + secLab, "; unconditionally jump"); // emit "jmp. L1; unconditionally jump"
  emit("." + firstLab + ":"); // emit ".L0: "
  emit("", "mov", "eax,[TRUE]", "; set eax to TRUE"); // emit "mov eax,[TRUE]; set eax to TRUE"

  if (symbolTable.count("true") == 0) // if true is not defined at data section
  {
    insert("true", BOOLEAN, CONSTANT, "-1", YES, 1); // insert true at .data SECTION
    symbolTable.at("true").setInternalName("TRUE"); // then change true to TRUE
  }
  emit("." + secLab + ":"); // emit ".L1: "

  if (isTemporary(operand1)) // if operand1 = "Tx"
  {
    freeTemp(); // currentTempNo--
  }
  if (isTemporary(operand2)) // // if operand2 = "Tx"
  {
    freeTemp(); // currentTempNo-- 
  }

  contentsOfAReg = getTemp(); // AReg = "Tx"
  symbolTable.at(contentsOfAReg).setDataType(BOOLEAN); // set datatype of AReg to BOOLEAN
  pushOperand(contentsOfAReg); // push AReg to Operand
}

/** LEXER FUNCTIONS **/
/*nextToken() catches LEXICAL ERRORS*/
string Compiler::nextToken() // returns the next token or end of file marker
{
  token = ""; // deassign token

  while (token == "")
  {
    if (ch == '{')
    {
      while (nextChar() && ch != END_OF_FILE && ch != '}')
      {
      }	// do nothing

      if (ch == END_OF_FILE)
      {
        processError("unexpected end of file");
      }
      else
      {
        nextChar();
      }
    }

    else if (ch == '}')
    {
      processError("'}' cannot begin token");
    }
    else if (isspace(ch))
    {
      nextChar();
    }
    else if (isSpecialSymbol(ch))
    {
      token = ch;
      nextChar();

      if (token == ":" && ch == '=')
      {
        token += ch;
        nextChar();
      }
      else if (token == "<" && (ch == '>' || ch == '='))
      {
        token += ch;
        nextChar();
      }
      else if (token == ">" && ch == '=')
      {
        token += ch;
        nextChar();
      }
    }

    else if (islower(ch))
    {
      token += ch;

      while ((nextChar() == '_' || (ch >= '0' && ch <= '9') || (ch >= 'a' && ch <= 'z')
        || (ch >= 'A' && ch <= 'Z')) && ch != END_OF_FILE)
        token += ch;

      if (ch == END_OF_FILE)
      {
        processError("unexpected end of file");
      }
    }

    else if (isdigit(ch))
    {
      token = ch;

      while (isdigit(nextChar()) && ch != END_OF_FILE
        && !isSpecialSymbol(ch))
      {
        token += ch;
      }
      if (ch == END_OF_FILE)
      {
        processError("unexpected end of file");
      }
    }

    else if (ch == END_OF_FILE)
    {
      token = ch;
    }
    else
    {
      processError("illegal symbol");
    }
  }
  token = token.substr(0, 15);

  return token;
}

char Compiler::nextChar() // returns the next character or end of file marker
{
  // get the next character
  sourceFile.get(ch);

  // set prevChar at the beginning so we know when to start
  // a new line number. Needs to be static because this fn is
  // called from outside repeatedly.
  static char prevChar = '\n';

  if (!sourceFile) // works like if(sourcefile.eof())
  {                // see Dr Motl's lecture from 11/01
    ch = END_OF_FILE;
    return ch;
  }

  else
  {
    if (prevChar == '\n')
    {
      // we have a new line, increment the
      // line number and add it to the left
      // with a separator
      listingFile << setw(5) << ++lineNo << '|';
    }
    // add the current character
    listingFile << ch;
  }

  // now set the previous character (static!) to the
  // current character. When we reach a new line again,
  // it will be reset to '\n'
  prevChar = ch;

  // done
  return ch;
}