original_string: public function ltrim($str, $charlist = null)
      {
          return isset($charlist) ? ltrim($str, $charlist) : ltrim($str);
      }
code: public function ltrim($str, $charlist = null)
      {
          return isset($charlist) ? ltrim($str, $charlist) : ltrim($str);
      }
code_tokens: public function ltrim ( $ str , $ charlist = null ) { return isset ( $ charlist ) ? ltrim ( $ str , $ charlist ) : ltrim ( $ str ) ; }
docstring: left trim string
  
  @param string $str
  @param array $charlist
  @return string
docstring_tokens: left trim string