public override bool TryMatchCurrent(LexerBuilder lexer)
{
if (lexer.Current == '/')
{
lexer.PeekNext();
if (lexer.Current == '/')
{
// line comment. read to end of line or file.
do
{
lexer.Commit();
lexer.PeekNext();
}while (!lexer.EndOrNewLine);
return(true);
}
else if (lexer.Current == '*')
{
// block comment, read until end of file or closing '*/'
lexer.PeekNext();
do
{
lexer.PeekNext();
lexer.Commit();
}while (!lexer.EndOfInput && !(lexer.Current == '/' && lexer.Previous == '*'));
return(true);
}
}
return(false);
}
public override bool TryMatchCurrent(LexerBuilder lexer)
{
var prev = lexer.Previous;
var first = lexer.Current;
// check for keywords
if (lexer.IsDelimiter(prev, true) && char.IsLetter(first))
{
// can be a keyword...
var sb = new StringBuilder();
sb.Append(lexer.Current);
while (!lexer.EndOfInput && char.IsLetter(lexer.PeekNext()))
{
sb.Append(lexer.Current);
}
if (keywords.Contains(sb.ToString()))
{
if (!lexer.EndOfInput)
{
lexer.RollbackBy(1);
}
lexer.Commit();
return(true);
}
return(false);
}
else
{
return(false);
}
}
public override bool TryMatchCurrent(LexerBuilder lexer)
{
// previous character must be delimiter, whitespace, or alphanumeric.
if (!lexer.IsDelimiter(lexer.Previous, true, true))
{
return(false);
}
if (IsSymbol(lexer.Current))
{
do
{
lexer.Commit();
lexer.PeekNext();
}while (IsSymbol(lexer.Current));
return(true);
}
return(false);
}
public override bool TryMatchCurrent(LexerBuilder lexer)
{
// previous character must be whitespace or delimiter
if (!lexer.IsDelimiter(lexer.Previous, true))
{
return(false);
}
if (!IsNumeric(lexer.Current))
{
return(false);
}
while (!lexer.EndOfInput)
{
lexer.Commit();
if (!IsNumeric(lexer.PeekNext()))
{
break;
}
}
return(true);
}
public override bool TryMatchCurrent(LexerBuilder lexer)
{
if (lexer.Current == '"')
{
if (lexer.Previous == '@')
{
// verbatim string, continue until un-escaped quote.
while (!lexer.EndOfInput)
{
lexer.Commit();
if (lexer.PeekNext() == '"')
{
lexer.Commit();
// possibly the end, check for escaped quotes.
// commit the character and flip the escape bool for each quote.
bool escaped = false;
while (lexer.PeekNext() == '"')
{
lexer.Commit();
escaped = !escaped;
}
// if the last quote wasnt escaped, that was the end of the string.
if (!escaped)
{
break;
}
}
}
}
else
{
// normal string
// continue until a quote which is not escaped, or end of input
while (!lexer.EndOfInput)
{
lexer.Commit();
lexer.PeekNext();
if ((lexer.Current == '"') && lexer.Previous != '\\')
{
lexer.Commit();
break;
}
}
}
return(true);
}
else if (lexer.Current == '\'')
{
// char
while (!lexer.EndOfInput)
{
lexer.Commit();
lexer.PeekNext();
if ((lexer.Current == '\'') && lexer.Previous != '\\')
{
lexer.Commit();
break;
}
}
return(true);
}
else
{
return(false);
}
}