public override Token Match(Lexer lexer)
{
bool isKeyword = false;
string word = string.Empty;
using (var la = new LookaheadFrame(lexer)) {
var c = lexer.NextChar();
if (IsIdentifierStartChar(c)) {
var tok = new Token() { Line = lexer.Line, Col = lexer.Col, Sym = Sym.Id };
var sb = new StringBuilder();
sb.Append(c);
while (IsIdentifierPartChar(lexer.Peek())) {
sb.Append(lexer.NextChar());
}
//Since the id rule tries to match before any
//reserved-word ones, we need to make sure this id isn't
//actually a keyword
word = sb.ToString();
isKeyword = lexer.KeywordTable.ContainsKey(word);
if (!isKeyword) {
la.Commit();
tok.Value = word;
return tok;
}
}
}
//If it is a kw, invoke that rule instead
if (isKeyword) {
return lexer.KeywordTable[word].Match(lexer);
}
return null;
}
public override Token Match(Lexer lexer)
{
var rem = lexer.RemainingInput;
if (lexer.CanRead) {
string value = null;
var match = singleCharRe.Match(rem);
if (match.Success) {
value = match.Value;
} else if ((match = escapeCharRe.Match(rem)).Success) {
value = match.Value;
} else if ((match = hexEscapeRe.Match(rem)).Success) {
value = match.Value;
} else if ((match = unicEscapeRe.Match(rem)).Success) {
value = match.Value;
}
if (null != value) {
var tok = new Token() { Line = lexer.Line, Col = lexer.Col };
tok.Sym = Sym.CharLiteral;
tok.Value = value.Substring(1, value.Length - 2); ;
lexer.Advance(value.Length);
return tok;
}
}
return null;
}
private string FormatError(string msg, Lexer lexer)
{
var tok = lexer.LastOne;
if (null == tok)
return msg;
return string.Format("Line {0}, col {1}: {2}", tok.Line, tok.Col, msg);
}
//TODO: 'Verbatim' string handling (e.g. @"...")
public override Token Match(Lexer lexer)
{
if (lexer.CanRead) {
var match = simpleLit.Match(lexer.RemainingInput);
if (match.Success) {
var tok = new Token() { Line = lexer.Line, Col = lexer.Col };
tok.Sym = Sym.StringLiteral;
tok.Value = match.Value.Substring(1, match.Value.Length - 2);
lexer.Advance(match.Value.Length);
return tok;
}
}
return null;
}
public override Token Match(Lexer lexer)
{
var tok = new Token() { Line = lexer.Line, Col = lexer.Col };
string rem = lexer.RemainingInput;
bool isMatch = false;
Match match = hexIntLit.Match(rem);
if (match.Success) {
tok.Value = match.Value;
tok.Sym = Sym.HexIntLiteral;
isMatch = true;
}
foreach (var re in realRes) {
match = re.Match(rem);
if (match.Success) {
tok.Value = match.Value;
tok.Sym = Sym.RealLiteral;
isMatch = true;
break;
}
}
if (!isMatch) {
match = decIntLit.Match(rem);
if (match.Success) {
tok.Value = match.Value;
tok.Sym = Sym.IntLiteral;
isMatch = true;
}
}
if (isMatch) {
lexer.Advance(tok.Value.Length);
return tok;
}
return null;
}
public void Error(string msg, Lexer lexer)
{
errors.Add(FormatError(msg, lexer));
}
public void TestLexicalMatch1()
{
var lexer = new Lexer("foo bar");
var rule = new LexicalRule("foo", Sym.KwClass);
Assert.IsNotNull(rule.Match(lexer));
}
