public BrainfuckTokenSequence Parse(TextReader streamReader, BrainfuckMemoryTape memoryTape = null)
{
memoryTape = memoryTape ?? new BrainfuckMemoryTape();
var leftBracketStack = new Stack <LeftBracketToken>();
BrainfuckToken first = null;
BrainfuckToken prev = null;
var index = -1;
while (0 <= streamReader.Peek())
{
++index;
var c = (char)streamReader.Read();
BrainfuckToken current = null;
switch (c)
{
case '>':
current = new RightShiftToken();
break;
case '<':
current = new LeftShiftToken();
break;
case '+':
current = new PlusToken();
break;
case '-':
current = new MinusToken();
break;
case '.':
current = new DotToken();
break;
case ',':
current = new SemicolonToken();
break;
case '[':
{
var leftBracket = new LeftBracketToken();
leftBracketStack.Push(leftBracket);
current = leftBracket;
}
break;
case ']':
{
if (leftBracketStack.Count == 0)
{
throw new InvalidOperationException();
}
var leftBracket = leftBracketStack.Pop();
var rightBracket = new RightBracketToken();
leftBracket.RightBracketToken = rightBracket;
rightBracket.LeftBracketToken = leftBracket;
current = rightBracket;
}
break;
default:
break;
}
if (current == null)
{
continue;
}
current.MemoryTape = memoryTape;
current.Index = index;
if (prev != null && prev.Next == null)
{
prev.SetNextIndexToken(current);
}
prev = current;
if (first != null)
{
continue;
}
first = current;
}
if (leftBracketStack.Count != 0)
{
throw new InvalidOperationException();
}
return(new BrainfuckTokenSequence(first));
}
public IEnumerable <BrainfuckToken> Parse(TextReader streamReader)
{
var ret = new List <BrainfuckToken>();
var leftBracketStack = new Stack <LeftBracketToken>();
BrainfuckToken prev = null;
var index = -1;
while (0 <= streamReader.Peek())
{
++index;
var c = (char)streamReader.Read();
BrainfuckToken current = null;
switch (c)
{
case '>':
current = new RightShiftToken();
break;
case '<':
current = new LeftShiftToken();
break;
case '+':
current = new PlusToken();
break;
case '-':
current = new MinusToken();
break;
case '.':
current = new DotToken();
break;
case ',':
current = new SemicolonToken();
break;
case '[':
{
var leftBracket = new LeftBracketToken();
leftBracketStack.Push(leftBracket);
current = leftBracket;
}
break;
case ']':
{
if (leftBracketStack.Count == 0)
{
throw new InvalidOperationException();
}
var leftBracket = leftBracketStack.Pop();
var rightBracket = new RightBracketToken();
leftBracket.RightBracketToken = rightBracket;
rightBracket.LeftBracketToken = leftBracket;
current = rightBracket;
}
break;
}
if (current == null)
{
continue;
}
current.Index = index;
prev?.SetNextIndexToken(current);
prev = current;
ret.Add(current);
}
if (leftBracketStack.Count != 0)
{
throw new InvalidOperationException();
}
return(ret);
}
public List <Token> Convert(string regexString)
{
var result = new List <Token>();
var currentCharIndex = 0;
var length = regexString.Length;
while (currentCharIndex != length)
{
var currentChar = regexString[currentCharIndex];
Token toAdd;
switch (currentChar)
{
case '(':
toAdd = new LeftBracketToken();
break;
case ')':
toAdd = new RightBracketToken();
break;
case '*':
toAdd = new StarToken();
break;
case '|':
toAdd = new SumToken();
break;
case '\\':
currentCharIndex++;
if (currentCharIndex == length)
{
throw new RegexParseException($"Backslash at the end of input escaping nothing.");
}
toAdd = new CharacterClassToken($"\\{regexString[currentCharIndex]}");
break;
case '[':
currentCharIndex++;
var startingIndex = currentCharIndex;
while (currentCharIndex != length && regexString[currentCharIndex] != ']')
{
// Escape inside character class
if ('\\'.Equals(regexString[currentCharIndex]))
{
currentCharIndex++;
}
currentCharIndex++;
}
if (currentCharIndex == length)
{
throw new RegexParseException($"Character class not properly closed in {regexString}");
}
var value = regexString.Substring(startingIndex, currentCharIndex - startingIndex);
toAdd = new CharacterClassToken(value);
break;
default:
toAdd = new CharacterClassToken($"\\{currentChar}");
break;
}
result.Add(toAdd);
currentCharIndex++;
}
return(result);
}
