std::string Token::tokenClassString() const
{
switch (tokenClass()) {
case TokenClass::Keyword: return "Keyword";
case TokenClass::Identifier: return "Identifier";
case TokenClass::Constant: return "Constant";
case TokenClass::StringLiteral: return "StringLiteral";
case TokenClass::Punctuator: return "Punctuator";
default: return "None";
}
}
tokenClass scannerClass::getToken()
{
int currentStateNum = 0;
int c;
string currentLexeme;
do
{
//First clear the buffer if it is a new state.
if(currentStateNum == 0)
currentLexeme = "";
c = (int)fileManager.getNextChar();
if(c == EOF)//Because EOF(-1) is not a valid index, we need to change it before using it in the matrix.
c = EOF_INDEX;
if(c >= MAX_CHAR)//If the char read is not within the range.
{
errorAndExit(("Illegal symbol: "+c));
return tokenClass(EOF_T,NONE_ST,"EOF");
}
State s = stateMatrix[currentStateNum][c];//Get the next state.
if(s.nextStateNum == INVALID_STATE)//If state is invalid, e.g. the char sequence is not recognized.
{
errorAndExit("Invalid char sequence: "+(currentLexeme+(char)c));
return tokenClass(EOF_T,NONE_ST,"EOF");
}
if(s.nextStateNum == EOF_INDEX)//If reached EOF, in this case no action needs to be taken.
return tokenClass(EOF_T,NONE_ST,"EOF");
switch(s.action)
{
case NO_ACTION:
currentLexeme += c;//Store the current char.
break;
case ACCEPT:
{
if(!s.needPushBack)
currentLexeme += c;
else
fileManager.pushBack();
int type = s.token->type;
if(type == INTEGER_T)//Check for interger length
if(currentLexeme.length() > 4)
{
errorAndExit("Integer can have at most four digits: "+currentLexeme);
return tokenClass(EOF_T,NONE_ST,"EOF");
}
if(type == STRING_T)//Check for string length
if(currentLexeme.length() > 52)
{
errorAndExit("String can have at most fifty characters: "+currentLexeme);
return tokenClass(EOF_T,NONE_ST,"EOF");
}
if(type == IDENTIFIER_T)//Check for identifier length
{
if(currentLexeme.length() > 12)
{
errorAndExit("Identifier can have at most twelve characters: "+currentLexeme);
return tokenClass(EOF_T,NONE_ST,"EOF");
}
//Here we check for the keywords
const char* cString = currentLexeme.c_str();
if(_strcmpi("or",cString)==0)
return tokenClass(ADDOP_T,OR_ST,currentLexeme);
if(_strcmpi("and",cString)==0)
return tokenClass(MULOP_T,AND_ST,currentLexeme);
if(_strcmpi("div",cString)==0)
return tokenClass(MULOP_T,DIV_ST,currentLexeme);
if(_strcmpi("mod",cString)==0)
return tokenClass(MULOP_T,MOD_ST,currentLexeme);
Keyword keywords[16]={PROGRAM_KEYWORD,FUNCTION_KEYWORD,BEGIN_KEYWORD,END_KEYWORD,IF_KEYWORD,THEN_KEYWORD,ELSE_KEYWORD,WHILE_KEYWORD,DO_KEYWORD,COUT_KEYWORD,CIN_KEYWORD,ENDL_KEYWORD,INT_KEYWORD,BOOLEAN_KEYWORD,TRUE_KEYWORD,FALSE_KEYWORD};
//char* keywords[16]={"program","function","begin","end","if","then","else","while","do","cout","cin","endl","int","boolean","true","false"};
for(int i = 0;i<16;i++)
if(_strcmpi(keywords[i].keyword,cString)==0)
return tokenClass(keywords[i].type,NONE_ST,currentLexeme);
}
return tokenClass(s.token->type,s.token->subtype,currentLexeme);
}
case WARNING_ACTION:
cout<<"warning"<<endl;//Currently not used because no warning state is checked by the state matrix.
break;
case ERROR_ACTION:
{
if(s.actionInfo != NULL)
errorAndExit(*s.actionInfo);
else //This else is only here as a double check. Normally an error message should be included.
errorAndExit("Error");
}
case CLEAR_BUFFER_ACTION:
currentLexeme = "";//Clear buffer, for comments only.
break;
case CHECK_COMPILER_DIRECTIVE_ACTION:
currentLexeme+=c;
if(currentLexeme == "{$p+}")
fileManager.setPrintStatus(true);
else if (currentLexeme == "{$p-}")
fileManager.setPrintStatus(false);
else if (currentLexeme == "{$e+}")
expressionDebugging = true;
else if (currentLexeme == "{$e-}")
expressionDebugging = false;
else if (currentLexeme == "{$s+}")
cout<<symbolTable.toString()<<endl;
else
cout<<"Warning, compiler directive "+currentLexeme+" is undefined."<<endl;
break;
}
currentStateNum = s.nextStateNum;
}
while(true);
//This should be unreachable
return tokenClass(EMPTY_T,EMPTY_ST,EMPTY_LEXEME);
}
