/// <summary>
/// required to override this function from base otherwise the parsetree will consist of incorrect types of nodes
/// </summary>
/// <param name="token"></param>
/// <param name="text"></param>
/// <returns></returns>
public override ParseNode CreateNode(Token token, string text)
{
ParseTreeEvaluator node = new ParseTreeEvaluator();
node.Token = token;
node.text = text;
node.Parent = this;
return node;
}
public void UpdateRange(Token token)
{
if (token.StartPos < startpos) startpos = token.StartPos;
if (token.EndPos > endpos) endpos = token.EndPos;
}
/// <summary>
/// executes a lookahead of the next token
/// and will advance the scan on the input string
/// </summary>
/// <returns></returns>
public Token Scan(params TokenType[] expectedtokens)
{
Token tok = LookAhead(expectedtokens); // temporarely retrieve the lookahead
LookAheadToken = null; // reset lookahead token, so scanning will continue
StartPos = tok.EndPos;
EndPos = tok.EndPos; // set the tokenizer to the new scan position
return tok;
}
/// <summary>
/// returns token with longest best match
/// </summary>
/// <returns></returns>
public Token LookAhead(params TokenType[] expectedtokens)
{
int i;
int startpos = StartPos;
Token tok = null;
List<TokenType> scantokens;
// this prevents double scanning and matching
// increased performance
if (LookAheadToken != null
&& LookAheadToken.Type != TokenType._UNDETERMINED_
&& LookAheadToken.Type != TokenType._NONE_) return LookAheadToken;
// if no scantokens specified, then scan for all of them (= backward compatible)
if (expectedtokens.Length == 0)
scantokens = Tokens;
else
{
scantokens = new List<TokenType>(expectedtokens);
scantokens.AddRange(SkipList);
}
do
{
int len = -1;
TokenType index = (TokenType)int.MaxValue;
string input = Input.Substring(startpos);
tok = new Token(startpos, EndPos);
for (i = 0; i < scantokens.Count; i++)
{
Regex r = Patterns[scantokens[i]];
Match m = r.Match(input);
if (m.Success && m.Index == 0 && ((m.Length > len) || (scantokens[i] < index && m.Length == len )))
{
len = m.Length;
index = scantokens[i];
}
}
if (index >= 0 && len >= 0)
{
tok.EndPos = startpos + len;
tok.Text = Input.Substring(tok.StartPos, len);
tok.Type = index;
}
else if (tok.StartPos < tok.EndPos - 1)
{
tok.Text = Input.Substring(tok.StartPos, 1);
}
if (SkipList.Contains(tok.Type))
{
startpos = tok.EndPos;
Skipped.Add(tok);
}
else
{
// only assign to non-skipped tokens
tok.Skipped = Skipped; // assign prior skips to this token
Skipped = new List<Token>(); //reset skips
}
}
while (SkipList.Contains(tok.Type));
LookAheadToken = tok;
return tok;
}
public void Init(string input)
{
this.Input = input;
StartPos = 0;
EndPos = 0;
CurrentLine = 0;
CurrentColumn = 0;
CurrentPosition = 0;
LookAheadToken = null;
}
public Token GetToken(TokenType type)
{
Token t = new Token(this.StartPos, this.EndPos);
t.Type = type;
return t;
}
public Scanner()
{
Regex regex;
Patterns = new Dictionary<TokenType, Regex>();
Tokens = new List<TokenType>();
LookAheadToken = null;
Skipped = new List<Token>();
SkipList = new List<TokenType>();
SkipList.Add(TokenType.WHITESPACE);
regex = new Regex(@"true|false", RegexOptions.Compiled);
Patterns.Add(TokenType.BOOLEANLITERAL, regex);
Tokens.Add(TokenType.BOOLEANLITERAL);
regex = new Regex(@"[0-9]+(UL|Ul|uL|ul|LU|Lu|lU|lu|U|u|L|l)?", RegexOptions.Compiled);
Patterns.Add(TokenType.DECIMALINTEGERLITERAL, regex);
Tokens.Add(TokenType.DECIMALINTEGERLITERAL);
regex = new Regex(@"([0-9]+\.[0-9]+([eE][+-]?[0-9]+)?([fFdDMm]?)?)|(\.[0-9]+([eE][+-]?[0-9]+)?([fFdDMm]?)?)|([0-9]+([eE][+-]?[0-9]+)([fFdDMm]?)?)|([0-9]+([fFdDMm]?))", RegexOptions.Compiled);
Patterns.Add(TokenType.REALLITERAL, regex);
Tokens.Add(TokenType.REALLITERAL);
regex = new Regex(@"0(x|X)[0-9a-fA-F]+", RegexOptions.Compiled);
Patterns.Add(TokenType.HEXINTEGERLITERAL, regex);
Tokens.Add(TokenType.HEXINTEGERLITERAL);
regex = new Regex(@"\""(\""\""|[^\""])*\""", RegexOptions.Compiled);
Patterns.Add(TokenType.STRINGLITERAL, regex);
Tokens.Add(TokenType.STRINGLITERAL);
regex = new Regex(@"[a-zA-Z_][a-zA-Z0-9_]*(?=\s*\()", RegexOptions.Compiled);
Patterns.Add(TokenType.FUNCTION, regex);
Tokens.Add(TokenType.FUNCTION);
regex = new Regex(@"[a-zA-Z_][a-zA-Z0-9_]*(?!\s*\()", RegexOptions.Compiled);
Patterns.Add(TokenType.VARIABLE, regex);
Tokens.Add(TokenType.VARIABLE);
regex = new Regex(@"(?i)pi|e", RegexOptions.Compiled);
Patterns.Add(TokenType.CONSTANT, regex);
Tokens.Add(TokenType.CONSTANT);
regex = new Regex(@"{\s*", RegexOptions.Compiled);
Patterns.Add(TokenType.BRACEOPEN, regex);
Tokens.Add(TokenType.BRACEOPEN);
regex = new Regex(@"\s*}", RegexOptions.Compiled);
Patterns.Add(TokenType.BRACECLOSE, regex);
Tokens.Add(TokenType.BRACECLOSE);
regex = new Regex(@"\(\s*", RegexOptions.Compiled);
Patterns.Add(TokenType.BRACKETOPEN, regex);
Tokens.Add(TokenType.BRACKETOPEN);
regex = new Regex(@"\s*\)", RegexOptions.Compiled);
Patterns.Add(TokenType.BRACKETCLOSE, regex);
Tokens.Add(TokenType.BRACKETCLOSE);
regex = new Regex(@",", RegexOptions.Compiled);
Patterns.Add(TokenType.COMMA, regex);
Tokens.Add(TokenType.COMMA);
regex = new Regex(@"\+\+", RegexOptions.Compiled);
Patterns.Add(TokenType.PLUSPLUS, regex);
Tokens.Add(TokenType.PLUSPLUS);
regex = new Regex(@"--", RegexOptions.Compiled);
Patterns.Add(TokenType.MINUSMINUS, regex);
Tokens.Add(TokenType.MINUSMINUS);
regex = new Regex(@"\|\|", RegexOptions.Compiled);
Patterns.Add(TokenType.PIPEPIPE, regex);
Tokens.Add(TokenType.PIPEPIPE);
regex = new Regex(@"&&", RegexOptions.Compiled);
Patterns.Add(TokenType.AMPAMP, regex);
Tokens.Add(TokenType.AMPAMP);
regex = new Regex(@"&(?!&)", RegexOptions.Compiled);
Patterns.Add(TokenType.AMP, regex);
Tokens.Add(TokenType.AMP);
regex = new Regex(@"\^", RegexOptions.Compiled);
Patterns.Add(TokenType.POWER, regex);
Tokens.Add(TokenType.POWER);
regex = new Regex(@"\+", RegexOptions.Compiled);
Patterns.Add(TokenType.PLUS, regex);
Tokens.Add(TokenType.PLUS);
regex = new Regex(@"-", RegexOptions.Compiled);
Patterns.Add(TokenType.MINUS, regex);
Tokens.Add(TokenType.MINUS);
regex = new Regex(@"=", RegexOptions.Compiled);
Patterns.Add(TokenType.EQUAL, regex);
Tokens.Add(TokenType.EQUAL);
regex = new Regex(@":=", RegexOptions.Compiled);
Patterns.Add(TokenType.ASSIGN, regex);
Tokens.Add(TokenType.ASSIGN);
regex = new Regex(@"!=|<>", RegexOptions.Compiled);
Patterns.Add(TokenType.NOTEQUAL, regex);
Tokens.Add(TokenType.NOTEQUAL);
regex = new Regex(@"!", RegexOptions.Compiled);
Patterns.Add(TokenType.NOT, regex);
Tokens.Add(TokenType.NOT);
regex = new Regex(@"\*", RegexOptions.Compiled);
Patterns.Add(TokenType.ASTERIKS, regex);
Tokens.Add(TokenType.ASTERIKS);
regex = new Regex(@"/", RegexOptions.Compiled);
Patterns.Add(TokenType.SLASH, regex);
Tokens.Add(TokenType.SLASH);
regex = new Regex(@"%", RegexOptions.Compiled);
Patterns.Add(TokenType.PERCENT, regex);
Tokens.Add(TokenType.PERCENT);
regex = new Regex(@"\?", RegexOptions.Compiled);
Patterns.Add(TokenType.QUESTIONMARK, regex);
Tokens.Add(TokenType.QUESTIONMARK);
regex = new Regex(@".", RegexOptions.Compiled);
Patterns.Add(TokenType.POINT, regex);
Tokens.Add(TokenType.POINT);
regex = new Regex(@"<=", RegexOptions.Compiled);
Patterns.Add(TokenType.LESSEQUAL, regex);
Tokens.Add(TokenType.LESSEQUAL);
regex = new Regex(@">=", RegexOptions.Compiled);
Patterns.Add(TokenType.GREATEREQUAL, regex);
Tokens.Add(TokenType.GREATEREQUAL);
regex = new Regex(@"<(?!>)", RegexOptions.Compiled);
Patterns.Add(TokenType.LESSTHAN, regex);
Tokens.Add(TokenType.LESSTHAN);
regex = new Regex(@">", RegexOptions.Compiled);
Patterns.Add(TokenType.GREATERTHAN, regex);
Tokens.Add(TokenType.GREATERTHAN);
regex = new Regex(@":", RegexOptions.Compiled);
Patterns.Add(TokenType.COLON, regex);
Tokens.Add(TokenType.COLON);
regex = new Regex(@"^$", RegexOptions.Compiled);
Patterns.Add(TokenType.EOF, regex);
Tokens.Add(TokenType.EOF);
regex = new Regex(@"\s+", RegexOptions.Compiled);
Patterns.Add(TokenType.WHITESPACE, regex);
Tokens.Add(TokenType.WHITESPACE);
}
public Token Join(Token tok)
{
if (type == TokenType.Operator && tok.type == TokenType.Number)
{
return Token.StringToToken(operand + tok.value);
}
else if (tok.type == TokenType.Operator && type == TokenType.Number)
{
return Token.StringToToken(tok.operand + value);
}
return null;
}
