Ripgrepping with Helm: the mode-line

Last time I tailored my own helm-do-grep-ag to show you how I use ripgrep within Helm. However, I missed something: the mode-line.

The default mode-line Helm offers for helm-do-grep-ag doesn’t fit well with my custom one, which is a minimal¹ version of the excellent doom-modeline. It’s a two-fold issue: my mode-line is bigger than the default one and I don’t need all the information usually printed by helm-do-grep-ag.

By inspecting Helm source code one can easily find out what helm-do-grep-ag does on mode-line-format. Basically, among other things helm-grep-ag-init sets up the value for mode-line-format according to the number of results. Very well, then, it’s time to bring el-patch back in the game.

First, though, aesthetics.

(set-face-bold 'helm-grep-finish t)

I am just making helm-grep-finish bold, nothing serious.

(el-patch-defun helm-grep-ag-init (directory &optional type)
  "Start AG process in DIRECTORY maybe searching only files of type TYPE."
  (let ((default-directory (or (el-patch-swap
                                 helm-ff-default-directory
                                 (mu--project-root))
                               (helm-default-directory)
                               default-directory))
        (cmd-line (helm-grep-ag-prepare-cmd-line
                   helm-pattern (or (file-remote-p directory 'localname)
                                    directory)
                   type))
        (el-patch-remove
          (start-time (float-time)))
        (proc-name (helm-grep--ag-command)))
    (set (make-local-variable 'helm-grep-last-cmd-line) cmd-line)
    (el-patch-remove
      (helm-log "Starting %s process in directory `%s'"
                proc-name directory)
      (helm-log "Command line used was:\n\n%s"
                (concat ">>> " cmd-line "\n\n")))
    (prog1
        (start-file-process-shell-command proc-name helm-buffer cmd-line)
      (set-process-sentinel
       (get-buffer-process helm-buffer)
       (lambda (process event)
         (let* ((err (process-exit-status process))
                (noresult (= err 1))
                (el-patch-add
                  (proc (concat " HELM " proc-name))))
           (el-patch-swap
             (cond (noresult
                    (with-helm-buffer
                      (insert (concat "* Exit with code 1, no result found,"
                                      " command line was:\n\n "
                                      (propertize helm-grep-last-cmd-line
                                                  'face 'helm-grep-cmd-line)))
                      (setq mode-line-format
                            `(" " mode-line-buffer-identification " "
                              (:eval (format "L%s" (helm-candidate-number-at-point))) " "
                              (:eval (propertize
                                      (format
                                       "[%s process finished - (no results)] "
                                       ,(upcase proc-name))
                                      'face 'helm-grep-finish))))))
                   ((string= event "finished\n")
                    (helm-log "%s process finished with %s results in %fs"
                              proc-name
                              (helm-get-candidate-number)
                              (- (float-time) start-time))
                    (helm-maybe-show-help-echo)
                    (with-helm-window
                      (setq mode-line-format
                            `(" " mode-line-buffer-identification " "
                              (:eval (format "L%s" (helm-candidate-number-at-point))) " "
                              (:eval (propertize
                                      (format
                                       "[%s process finished in %.2fs - (%s results)] "
                                       ,(upcase proc-name)
                                       ,(- (float-time) start-time)
                                       (helm-get-candidate-number))
                                      'face 'helm-grep-finish))))
                      (force-mode-line-update)
                      (when helm-allow-mouse
                        (helm--bind-mouse-for-selection helm-selection-point))))
                   (t (helm-log
                       "Error: %s %s"
                       proc-name
                       (replace-regexp-in-string "\n" "" event))))
             (if noresult
                 (with-helm-buffer
                   (setq mode-line-format
                         `(""
                           mu-mode-line-bar
                           " "
                           (:eval
                            (propertize
                             (format "%s [no results]" ,proc)
                             'face 'helm-grep-finish)))))
               (with-helm-window
                 (setq mode-line-format
                       `(""
                         mu-mode-line-bar
                         " "
                         (:eval
                          (propertize
                           (format "%s [%s results]"
                                   ,proc (helm-get-candidate-number))
                           'face 'helm-grep-finish))))
                 (force-mode-line-update))))))))))

Let’s break down my changes:

(default-directory (el-patch-swap
                     (or helm-ff-default-directory
                         (helm-default-directory)
                         default-directory)
                     (or (mu--project-root)
                         (helm-default-directory)
                         default-directory)))

This has nothing do to with the mode-line, actually, but why not re-use mu–-project-root here? Exactly.

I also removed all the helm-log references, because I am confident my Elisp-fu will not need debugging.² Anyway, I want the buffer identification to look like the rest of the Helm buffer identifications in my mode-line:

(proc (concat " HELM " proc-name))

I am going to use only ripgrep for my searches, so proc-name is usually rg here, but one never knows what will come next.

When there are no results to be shown, I don’t want a message in the Helm buffer, just a clean feedback:

(setq mode-line-format
      `((:eval mu-mode-line-bar)
        " "
        (:eval
         (propertize
          (format "%s [no results]" ,proc)
          'face 'helm-grep-finish))))

The same goes for one or more results:

(setq mode-line-format
      `((:eval mu-mode-line-bar)
        " "
        (:eval
         (propertize
          (format "%s [%s results]"
                  ,proc
                  (helm-get-candidate-number))
          'face 'helm-grep-finish))))

mu-mode-line-bar is what makes my mode-line bigger and I borrowed it from doom-mode-line, so go check its fantastic code to find out about this magic trick.

Finally, this is how the mode-line looks after M-? when the ripgrep process finishes:

And for the sake of completeness, this is how it looks when I move through the results with C-p and C-n :

By the way, the colours are courtesy of modus-vivendi, a great theme by Protesilaos Stavrou I’ve recently switched to.