/// next reads the next rune from the bufferred reader. Returns the rune(0) if
/// an error occurs (or io.EOF is returned).
private char Next()
{
var(ch, size, err) = _buf.ReadRune();
if (err)
{
// advance for error reporting
_srcPos.Column++;
_srcPos.Offset += size;
_lastCharLen = size;
return(EOF);
}
if (ch == GoBuffer.RuneError && size == 1)
{
_srcPos.Column++;
_srcPos.Offset += size;
_lastCharLen = size;
Err("illegal UTF-8 encoding");
return(ch);
}
// remember last position
_prevPos = _srcPos;
_srcPos.Column++;
_lastCharLen = size;
_srcPos.Offset += size;
if (ch == '\n')
{
_srcPos.Line++;
_lastLineLen = _srcPos.Column;
_srcPos.Column = 0;
}
// If we see a null character with data left, then that is an error
if (ch == '\x00' && _buf.Len() > 0)
{
Err("unexpected null character (0x00)");
return(EOF);
}
// debug
// fmt.Printf("ch: %q, offset:column: %d:%d\n", ch, s.srcPos.Offset, s.srcPos.Column)
return(ch);
}