public void ParseValid_IntegerToken()
{
bool expected = true;
string s = "12";
bool actual = IntegerAutomaton.Parse(s);
Assert.AreEqual(expected, actual);
}
public void ParseInvalid_IntegerToken()
{
bool expected = false;
string s = "a";
bool actual = IntegerAutomaton.Parse(s);
Assert.AreEqual(expected, actual);
}
/// <summary>
/// Parse the input string for the first token
/// </summary>
/// <param name="s"></param>
/// <returns></returns>
public Token GetNextToken(ref string s)
{
var listOfPossibleTypes = new List <KeyValuePair <TokenType, int> >(10);
var sb = new StringBuilder(s.First().ToString());
Token token = null;
int posInString = 0;
int tokenLength = 0;
bool automatonAcceptFlag = false;
if (sb[0] == '(')
{
token = new Token("(", TokenType.LeftParen);
}
else if (sb[0] == ')')
{
token = new Token(")", TokenType.RightParen);
}
if (token != null)
{
scannedTokens.Add(token);
return(token);
}
do
{
if (sb[sb.Length - 1] == ')' && !StringAutomaton.ParsePartialString(sb.ToString()))
{
// Remove the last parenthesis
sb = sb.Remove(sb.Length - 1, 1);
break;
}
automatonAcceptFlag = false;
if (OperatorAutomaton.Parse(sb.ToString()))
{
listOfPossibleTypes.Add(new KeyValuePair <TokenType, int>(TokenType.Operator, tokenLength));
automatonAcceptFlag = true;
}
if (KeywordAutomaton.Parse(sb.ToString()))
{
listOfPossibleTypes.Add(new KeyValuePair <TokenType, int>(TokenType.Keyword, tokenLength));
automatonAcceptFlag = true;
}
if (BooleanAutomaton.Parse(sb.ToString()))
{
listOfPossibleTypes.Add(new KeyValuePair <TokenType, int>(TokenType.Boolean, tokenLength));
automatonAcceptFlag = true;
}
if (RealAutomaton.Parse(sb.ToString()))
{
listOfPossibleTypes.Add(new KeyValuePair <TokenType, int>(TokenType.Real, tokenLength));
automatonAcceptFlag = true;
}
if (IntegerAutomaton.Parse(sb.ToString()))
{
listOfPossibleTypes.Add(new KeyValuePair <TokenType, int>(TokenType.Integer, tokenLength));
automatonAcceptFlag = true;
}
if (StringAutomaton.Parse(sb.ToString()))
{
listOfPossibleTypes.Add(new KeyValuePair <TokenType, int>(TokenType.String, tokenLength));
automatonAcceptFlag = true;
}
if (IdentifierAutomaton.Parse(sb.ToString()))
{
listOfPossibleTypes.Add(new KeyValuePair <TokenType, int>(TokenType.Identifier, tokenLength));
automatonAcceptFlag = true;
}
if (!automatonAcceptFlag && StringAutomaton.ParsePartialString(sb.ToString()))
{
automatonAcceptFlag = true;
}
if (automatonAcceptFlag)
{
tokenLength++;
posInString++;
sb.Append(s.Length != posInString ? s.ElementAt(posInString) : ' ');
}
} while (automatonAcceptFlag);
var check = listOfPossibleTypes.Select(x => x.Key);
if (check.Contains(TokenType.Integer) && !check.Contains(TokenType.Real))
{
foreach (var c in sb.ToString())
{
if (!char.IsDigit(c) && c != ' ')
{
throw new InvalidOperationException(string.Format("Lexical scanner could not parse token {0}, exiting.", sb.ToString()));
}
}
}
if (check.Contains(TokenType.Real))
{
foreach (var c in sb.ToString())
{
if (!char.IsDigit(c) && c != '.' && c != ' ')
{
throw new InvalidOperationException(string.Format("Lexical scanner could not parse token {0}, exiting.", sb.ToString()));
}
}
}
// order the possible types by the key
var orderedByKey = listOfPossibleTypes
.OrderByDescending(x => x.Value);
// grab the longest-length value with the highest priority type
var result = orderedByKey
.Where(x => x.Value == orderedByKey.First().Value)
.OrderBy(x => x.Key)
.First();
// construct the token with result
token = new Token(
sb.ToString().Substring(0, result.Value + 1),
result.Key);
scannedTokens.Add(token);
return(token);
}