/// <summary>Parses an LES2-style identifier such as <c>foo</c>, <c>@foo</c>,
/// <c>@`foo`</c> or <c>@--punctuation--</c>.
/// </summary>
/// <param name="source">Text to parse. On return, the range has been
/// decreased by the length of the token; this method also stops if this
/// range becomes empty.</param>
/// <param name="onError">A method to call on error</param>
/// <param name="checkForNamedLiteral">This is set to true when the input
/// starts with @ but doesn't use backquotes, which could indicate that
/// it is an LES named literal such as @false or @null.</param>
/// <returns>The parsed version of the identifier.</returns>
public static string ParseIdentifier(ref UString source, Action <int, string> onError, out bool checkForNamedLiteral)
{
checkForNamedLiteral = false;
StringBuilder parsed = TempSB();
UString start = source;
bool fail;
int c = source.PopFirst(out fail);
if (c == '@')
{
// expecting: (BQString | Star(Set("[0-9a-zA-Z_'#~!%^&*-+=|<>/?:.@$]") | IdExtLetter))
c = source.PopFirst(out fail);
if (c == '`')
{
Les3Lexer.UnescapeString(ref source, (char)c, false, onError, parsed);
}
else
{
while (SpecialIdSet.Contains(c) || c >= 128 && char.IsLetter((char)c))
{
parsed.Append((char)c);
c = source.PopFirst(out fail);
}
checkForNamedLiteral = true;
}
}
else if (IsIdStartChar(c))
{
parsed.Append(c);
for (;;)
{
c = source.PopFirst(out fail);
if (!IsIdContChar(c))
{
break;
}
parsed.Append((char)c);
}
}
return(parsed.ToString());
}
public static bool UnescapeString(ref UString sourceText, char quoteType, bool isTripleQuoted, Action <int, string> onError, StringBuilder sb, UString indentation = default(UString), bool les3TQIndents = false) => Les3Lexer.UnescapeString(ref sourceText, quoteType, isTripleQuoted, onError, sb, indentation, les3TQIndents);