search.lisp

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(in-package :reddit)

(defun search-char (c)
  "T if c is an a letter, number, or '"
  (or (alphanumericp c)
      (member c '(#\' #\space #\")))) 

(defmacro rra (rex new str)
  "Make regex-replace-all lest awkward to type"
  `(regex-replace-all ,rex ,str ,new))
  
(defun to-search-str (str)
  "Formats the incoming str into a valid tsearch string"
  (rra "(?i) or | " "|"
       (rra "\\s+$" ""
            (rra "^\\s+" ""
                 (rra "(?i) and " "&"
                      (rra "\\s+" " "
                           (rra "\\\"" "'" 
                                (remove-if-not #'search-char str))))))))
                     
(defun search-sites (str &optional (limit 25) (offset 0))
  (when (> (length str) 0)
    (let ((q (format nil "to_tsquery('default', ~a)" (sql (to-search-str str)))))
      (select 'article-with-sn
              :where (sql-expression :string (format nil "idxfti @@ ~a" q))
              :order-by `((,(sql-expression :string (format nil "rank(idxfti, ~a)" q)) desc)
                          (,[articles_sn date] desc))
              :offset offset
              :limit limit
              :flatp t))))