public static bool TryFindNumber(CompilationPool pool)
{
if (!char.IsDigit(pool.Code[pool.CodePosition]))
{
return(false);
}
var startIndex = pool.CodePosition;
var isDouble = false;
for (; pool.CodePosition < pool.Code.Length; pool.CodePosition++)
{
if (char.IsDigit(pool.Code[pool.CodePosition]))
{
continue;
}
if (pool.Code[pool.CodePosition] == '.' && isDouble == false)
{
isDouble = true;
continue;
}
break;
}
pool.Tokens.Add(new Token(TokenClass.Literal, 0,
pool.Code.Substring(startIndex, pool.CodePosition - startIndex)));
return(true);
}
public static bool IsIndentifier(CompilationPool pool)
{
var identifierName = GetIdentifierName(pool);
if (identifierName.Length == 0)
{
return(false);
}
pool.CodePosition += identifierName.Length;
var existingIdenfitier =
pool.Identifiers.FirstOrDefault(
identifier => identifier.Identity.Equals(identifierName) && identifier.ScopeLevel.Equals(Scope));
if (existingIdenfitier == null)
{
pool.Identifiers.Add(new Identifier(identifierName));
}
pool.Tokens.Add(new Token(TokenClass.Identifier,
existingIdenfitier == null
? pool.Identifiers.Count - 1
: pool.Identifiers.IndexOf(existingIdenfitier), identifierName));
return(true);
}
private bool TryFindToken(CompilationPool pool)
{
for (var stateNumber = 0;; pool.CodePosition++)
{
var state = _states.ElementAt(stateNumber);
var symbol = pool.Code[pool.CodePosition];
if (!HasNextSymbol(pool, _tokenClass))
{
if (state.Transitions.ContainsKey(symbol))
{
state = _states.ElementAt(state.Transitions[symbol]);
}
else
{
return(false);
}
// last chanсe to determine token
if (!state.IsFinal)
{
return(false);
}
pool.Tokens.Add(new Token(_tokenClass, state.TokenNumber));
pool.CodePosition++;
return(true);
}
var subStateNumber = state.Transitions.Where(pair => pair.Key.Equals(symbol)).Select(pair => pair.Value)
.FirstOrDefault();
if (subStateNumber != 0)
{
var subState = _states.ElementAt(subStateNumber);
if (!subState.Transitions.Any() && subState.IsFinal)
{
pool.Tokens.Add(new Token(_tokenClass, subState.TokenNumber));
pool.CodePosition++;
return(true);
}
}
if (!state.Transitions.ContainsKey(symbol))
{
return(false);
}
// go to next state
stateNumber = state.Transitions[symbol];
}
}
public bool FindToken(CompilationPool pool)
{
var currentPosition = pool.CodePosition;
if (TryFindToken(pool))
{
return(true);
}
// if token not found, restore code-cursor position
pool.CodePosition = currentPosition;
return(false);
}
public static bool IsLiteral(CompilationPool pool)
{
var currentPosition = pool.CodePosition;
if (TryFindString(pool))
{
return(true);
}
if (TryFindNumber(pool))
{
return(true);
}
pool.CodePosition = currentPosition;
return(false);
}
private static string GetIdentifierName(CompilationPool pool)
{
var position = pool.CodePosition;
if (!char.IsLetterOrDigit(pool.Code[position]))
{
return("");
}
while (char.IsLetterOrDigit(pool.Code[position]) ||
pool.Code[position].Equals('_') && position < pool.Code.Length)
{
position++;
}
return(pool.Code.Substring(pool.CodePosition, position - pool.CodePosition));
}
public static bool TryFindString(CompilationPool pool)
{
if (pool.Code[pool.CodePosition] != '"')
{
return(false);
}
var index = pool.Code.IndexOf('"', pool.CodePosition + 1);
if (index == -1)
{
return(false);
}
pool.Tokens.Add(new Token(TokenClass.Literal, 0,
pool.Code.Substring(pool.CodePosition + 1, index - pool.CodePosition - 1)));
pool.CodePosition = index + 1;
return(true);
}
public static bool HasNextSymbol(CompilationPool pool, TokenClass tokenClass)
{
if (pool.CodePosition + 1 == pool.Code.Length)
{
return(false);
}
var symbol = pool.Code[pool.CodePosition + 1].ToString();
if (Constraints.Instance.Tokens.SkippedSymbols.Contains(symbol[0]))
{
return(false);
}
if (Constraints.Instance.Borders.ForSpecialChars.Contains(symbol))
{
return(false);
}
var result = Constraints.Instance.Borders.ForTokenClasses[tokenClass].Contains(symbol);
return(result);
}
