private static IEnumerable <IToken> Lex(CodeFile file, Diagnostics diagnostics)
{
var code = file.Code;
var text = code.Text;
var tokenStart = 0;
var tokenEnd = -1; // One past the end position to allow for zero length spans
while (tokenStart < text.Length)
{
var currentChar = text[tokenStart];
switch (currentChar)
{
case '{':
yield return(TokenFactory.OpenBrace(SymbolSpan()));
break;
case '}':
yield return(TokenFactory.CloseBrace(SymbolSpan()));
break;
case '(':
yield return(TokenFactory.OpenParen(SymbolSpan()));
break;
case ')':
yield return(TokenFactory.CloseParen(SymbolSpan()));
break;
case '[':
case ']':
case '|':
case '&':
case '@':
case '`':
case '$':
yield return(NewReservedOperator());
break;
case ';':
yield return(TokenFactory.Semicolon(SymbolSpan()));
break;
case ',':
yield return(TokenFactory.Comma(SymbolSpan()));
break;
case '#':
switch (NextChar())
{
case '#':
// it is `##`
yield return(NewReservedOperator(2));
break;
case '(':
// it is `#(`
yield return(NewReservedOperator(2));
break;
case '[':
// it is `#[`
yield return(NewReservedOperator(2));
break;
case '{':
// it is `#{`
yield return(NewReservedOperator(2));
break;
default:
// it is `#`
yield return(NewReservedOperator());
break;
}
break;
case '.':
if (NextChar() is '.')
{
if (CharAt(2) is '<')
{
// it is `..<`
yield return(TokenFactory.DotDotLessThan(SymbolSpan(3)));
}
else
{
// it is `..`
yield return(TokenFactory.DotDot(SymbolSpan(2)));
}
}
else
{
yield return(TokenFactory.Dot(SymbolSpan()));
}
break;
case ':':
if (NextChar() is ':' && CharAt(2) is '.')
{
// it is `::.`
yield return(TokenFactory.ColonColonDot(SymbolSpan(3)));
}
else
{
// it is `:`
yield return(TokenFactory.Colon(SymbolSpan()));
}
break;
