helm-clojure-headlines

helm-clojure-headlines.el

;; Might want to customize helm-candidate-number-limit, because by
;; default it shows 100 matches maximum.

;; FIXME: collect line count, and display if it's past helm-candidate-number-limit.

(defun helm-headlines (headline buffer-name good-regex exception-regex)
  "Display headlines for the current file.

   Displays lines where good-regex matches, except for those
   which also match exception-regex."
  ;; Fixes bug where the current buffer sometimes isn't used
  (setq helm-current-buffer (current-buffer))
  
  ;; https://groups.google.com/forum/#!topic/emacs-helm/YwqsyRRHjY4
  (jit-lock-fontify-now)
  (let* ((line-count 0)
         (data (with-helm-current-buffer
                 (goto-char (point-min))
                 (cl-loop while (re-search-forward good-regex nil t)
                          for line = (buffer-substring (point-at-bol)
                                                       (point-at-eol))
                          for pos = (line-number-at-pos)
                          unless (and exception-regex
                                      (string-match-p exception-regex line))
                          collect (propertize line 'helm-realvalue pos)
                          and do (incf line-count))))
         (headline (if (< helm-candidate-number-limit line-count)
                       (format "%s (initially showing only %s lines; %s is %s)"
                               headline
                               line-count
                               'helm-candidate-number-limit
                               helm-candidate-number-limit)
                     headline)))
    (helm :sources (helm-build-in-buffer-source headline
                     :data data
                     :get-line 'buffer-substring
                     :action (lambda (c) (helm-goto-line c)))
          :buffer buffer-name)))

(defun helm-clojure-headlines ()
  "Display headlines for the current Clojure file."
  (interactive)
  (helm-headlines "Clojure headlines"
                  "helm-clojure-headlines"
                  "^(\\|^;* [a-zA-Z]+"
                  nil))

(defun helm-python-headlines ()
  "Display headlines for the current Python file."
  (interactive)
  (helm-headlines "Python headlines"
                  "helm-python-headlines"
                  "\\(^[[:space:]]*\\(def\\|class\\)\\)\\|^#"
                  nil))