private bool HasKeyword()
{
return(Grammar.Keywords.Keys.Any(k =>
{
if (k == null)
{
throw new ArgumentNullException(nameof(k));
}
var p1 = _source.ElementAtOrDefault(_currentCharOffset + k.Length);
return !CharacterUtilities.IsDigitLetterOrUnderscore(p1) &&
string.Equals(PeekMany(k.Length), k, StringComparison.InvariantCultureIgnoreCase);
}));
}
private SyntaxNode Scan()
{
_state = (SafePeekChar(), SafePeekCharP1()) switch
{
var(c1, _) when c1.HasValue&& CharacterUtilities.IsWhitespace(c1.Value) => ScannerState.Whitespace,
('<', _) => ScannerState.Html,
('/', '/') => ScannerState.LineComment,
('/', '*') => ScannerState.BlockComment,
('#', _) => ScannerState.Preprocessor,
var(c1, c2) when c1.HasValue &&
c2.HasValue &&
Grammar.Punctuation.ContainsKey($"{c1.Value}{c2.Value}") =>
ScannerState.Punctuation2,
var(c1, _) when c1.HasValue&& Grammar.Punctuation.ContainsKey($"{c1.Value}") => ScannerState
.Punctuation1,
('"', _) => ScannerState.String,
var(c1, _) when c1.HasValue&& char.IsDigit(c1.Value) => ScannerState.Number,
('.', var c2)when c2.HasValue && char.IsDigit(c2.Value) => ScannerState.Number,
('-', var c2)when c2.HasValue && (char.IsDigit(c2.Value) || c2.Value == '.') => ScannerState.Number,
var(c1, _) when c1.HasValue&& char.IsLetter(c1.Value) => HasKeyword()
? ScannerState.Keyword
: ScannerState.Id,
var(c1, _) when c1.HasValue&& CharacterUtilities.IsDigitLetterOrUnderscore(c1.Value) => ScannerState
.Id,
_ => ScannerState.Nothing
};
if (_state == ScannerState.Nothing)
{
return(null);
}
NextNode();
return(_currentNode);
}
private SyntaxToken ScanId()
{
_scratch.Clear();
var start = _currentCharOffset;
if (!char.IsLetter(CurrentChar) && CurrentChar != '_')
{
throw GetException($"Expecting letter or _, found {CurrentChar}.");
}
_scratch.Append(CurrentChar);
NextChar();
while (true)
{
if (Empty())
{
break;
}
var c = CurrentChar;
if (CharacterUtilities.IsDigitLetterOrUnderscore(c))
{
_scratch.Append(c);
}
else
{
break;
}
NextChar();
}
return(new StringSyntax(SyntaxKind.IdToken, start, _currentCharOffset - start, _scratch.ToString()));
}