protected void AddTransition(TokenType oldState, char c, TokenType newState)
{
var key = new TokenizerTableKey(oldState, c);
if (table.ContainsKey(key))
{
throw new Exception(string.Format("Tokenizer.AddTransition() : The key [{0}, {1}] already exists in the transition table", oldState, c));
}
table[key] = newState;
}
// Return the next valid token read from the specified file stream.
// Read buffered characters before reading new characters from fp.
protected override Token GetToken()
{
var state_list = new List <TokenType>(); // List of states corresponding to not-yet-accepted characters
char c; // A character read from get_char()
var start_col = col_num; // The column of the first char in a token
var s = TokenType.S_Start; // Current state
sbToken.Clear();
state_list.Add(s);
for ( ; ;) // Loop until valid token read
{
char cSimplified;
c = GetChar();
if (char.IsLetter(c))
{
cSimplified = 'A';
}
else if (char.IsDigit(c))
{
cSimplified = '0';
}
else
{
cSimplified = c;
}
if (s != TokenType.S_Start && (c == '\0' || c == '\n' ||
(char.IsWhiteSpace(c) && !dictInternalStringStateToCompletedState.ContainsKey(s))))
{
if (dictInternalStringStateToCompletedState.ContainsKey(s) && (c == '\0' || c == '\n')) // Newline or EOF delimits string literal
{
s = dictInternalStringStateToCompletedState[s];
}
if (c == '\n')
{
++char_num;
}
if (acceptableTokens.Contains(s))
{
// Valid token has been delimited by white space
break;
}
else
{
// Error - try to recover
s = TokenType.S_Error;
}
}
TokenType newState;
if (s == TokenType.S_Start && c == '\0')
{
newState = TokenType.T_EOF;
}
else if (s == TokenType.S_Start && c == '\n')
{
++line_num;
col_num = 1;
start_col = 1; // Don't buffer white space
newState = s; // TokenType.S_Start;
}
else if (s == TokenType.S_Start && char.IsWhiteSpace(c))
{
++start_col; // Don't buffer white space
newState = s; // TokenType.S_Start;
}
else if (s == TokenType.S_Start && removeComments && c == cCommentDelimiter)
{
for (; ;)
{
++char_num;
c = GetChar();
if (c == '\0')
{
newState = TokenType.T_EOF;
break;
}
else if (c == '\n')
{
++line_num;
col_num = 1;
start_col = 1; // Don't buffer white space
newState = s; // TokenType.S_Start;
break;
}
}
}
#if DEAD_CODE
else if (s == TokenType.S_StrLitOpen && c != cStringDelimiter)
{
newState = s;
}
#else
else if (dictInternalStringStateToDelimiter.ContainsKey(s) && c != dictInternalStringStateToDelimiter[s])
{
newState = s;
}
#endif
else
{
var key = new TokenizerTableKey(s, cSimplified);
if (table.ContainsKey(key))
{
newState = table[key];
}
else
{
newState = TokenType.S_Error;
}
}
s = newState;
if (s == TokenType.T_EOF)
{
break;
}
else if (s == TokenType.S_Error)
{
s = RecoverToken(state_list);
if (s != TokenType.S_Error)
{
var rewindAmount = col_num - (start_col + sbToken.Length);
char_num -= rewindAmount;
col_num = start_col + sbToken.Length;
break; // Valid token recovered
}
throw new TokenizerException(string.Format("Lexical error at line {0}, column {1}", line_num, start_col), line_num, start_col);
/*
* Console.WriteLine("Discarding unmatched '{0}' at column {1}", m_str[start_col], start_col);
* was_err = true;
* strlit.Clear();
++start_col;
* col_num = start_col;
* token_str.Clear();
* s = TokenType.S_Start; // Start over at next unmatched char
* state_list.Clear();
* state_list.Add(s);
*/
}
else
{
++char_num;
if (c != '\n')
{
++col_num;
}
if (s != TokenType.S_Start)
{
sbToken.Append(c);
state_list.Add(s);
}
}
}
if (!acceptableTokens.Contains(s))
{
throw new TokenizerException(
string.Format("Internal error at line {0}, column {1}: Non-token {2} accepted", line_num, start_col, s),
line_num, start_col);
}
//Console.WriteLine("Token: {0} ; Line {1}; Column: {2}", sbToken.ToString(), line_num, start_col);
var token_str = sbToken.ToString();
object tokenValue;
switch (s)
{
case TokenType.T_IntLit:
tokenValue = int.Parse(token_str);
break;
case TokenType.T_FltLit:
tokenValue = double.Parse(token_str);
break;
case TokenType.T_StrLit:
tokenValue = GetStrLitFromTokenStr(cStringDelimiter);
break;
case TokenType.T_EOF:
tokenValue = "EOF";
break;
default:
tokenValue = ExtendedGetTokenValue(ref s, token_str); // TODO: Pass s by reference so that the Prolog interpreter can change it in the case of single-quoted strings -> identifiers.
if (tokenValue == null)
{
tokenValue = token_str.ToString();
}
break;
}
var token = new Token(s, tokenValue, line_num, start_col);
if (c == '\n')
{
++line_num;
col_num = 1;
}
return(token);
}