private static function strToTokens($str)
{
// Multi-pass segmentation
$node = new Token(ExpType::$RAW, $str);
$tokenStream = array($node);
$tokenStream = ExpLexer::divideString($tokenStream);
$tokenStream = ExpLexer::divideBlank($tokenStream);
$tokenStream = ExpLexer::divideKey($tokenStream, ExpLexer::$FUNCTION_PATTERN, 'functionHandler');
$tokenStream = ExpLexer::divideKey($tokenStream, ExpLexer::$TERNARY_PATTERN, 'ternaryHandler');
$tokenStream = ExpLexer::divideKey($tokenStream, ExpLexer::$PAREN_PATTERN, 'parenHandler');
$tokenStream = ExpLexer::divideKey($tokenStream, ExpLexer::$COMMA_PATTERN, 'commaHandler');
$tokenStream = ExpLexer::divideKey($tokenStream, ExpLexer::$OPERATOR_PATTERN, 'operatorHandler');
$tokenStream = ExpLexer::divideFloating($tokenStream);
$tokenStream = ExpLexer::divideKey($tokenStream, ExpLexer::$OPERATOR_PATTERN2, 'operatorHandler2');
$tokenStream = ExpLexer::divideDot($tokenStream);
ExpLexer::distinguishOperator($tokenStream);
return $tokenStream;
}
