protected function selector()
    {
        $factor = null;

        // first factor
        if (!$factor = $this->is("factor")) {
            return false;
        }
        $selector = new CssParserModelSelector();
        $selector->addFactor($factor);

        // additional factors
        while ($factor = $this->is("factor")) {
            $selector->addFactor($factor);
        }

        return $selector;
    }
protected function selector()
    {
        $factor = null;

        // first factor
        if (!$factor = $this->is("factor")) {
            return false;
        }
        $selector = new CssParserModelSelector();
        $selector->addFactor($factor);

        // additional factors
        while ($factor = $this->is("factor")) {
            $selector->addFactor($factor);
        }

        return $selector;
    }
protected function selector ( ) { $ factor = null ; // first factor if ( ! $ factor = $ this -> is ( "factor" ) ) { return false ; } $ selector = new CssParserModelSelector ( ) ; $ selector -> addFactor ( $ factor ) ; // additional factors while ( $ factor = $ this -> is ( "factor" ) ) { $ selector -> addFactor ( $ factor ) ; } return $ selector ; }
Is the next thing a selector?

A selector is a list of factors. The following example is a selector:
```
div > div.class h2[title = 'main-title'] + h3
```

In the above example, the following strings are factors:
```
div
> div.class
h2[title = 'main-title']
+ h3
```

@return false|CssParserModelSelector
Is the next thing a selector?