selectrum: improve SPC b b

- Now uses a consult backend
- has buffer preview, per workspace narrowing with `$n SPC`

modules/completion/selectrum/README.org

@@ -133,7 +133,12 @@ An ~occur-edit~ buffer can be opened from ~consult-line~ with =C-c C-e=.
 | =SPC b b=, =SPC ,=   | Switch to buffer in current workspace |
 | =SPC b B=, =SPC <=   | Switch to buffer                      |
 
-~find-file~ commands support exported to a =wdired= buffer using =C-c C-e=.
+=SPC b b= and =SPC ,= support changing the workspace you're selecting a buffer from
+via [[https://github.com/minad/consult#narrowing-and-grouping][Consult narrowing]], e.g. if you're on the first workspace, you can switch to
+selecting a buffer from the third workspace by typing =3 SPC= into the prompt,
+or the last workspace by typing =0 SPC=.
+
+=SPC f f= and =SPC .= support exporting to a =wdired= buffer using =C-c C-e=.
 
 *** Search
 | Keybind   | Description                               |

modules/completion/selectrum/TODO.org

@@ -70,16 +70,12 @@ currently =SPC n b= is bound to a function, but =bibtex-actions= doesn't have a
 main dispatch function like =ivy-bibtex=, rather it has a bunch of different
 ones. Binding the ~bibtex-actions-map~ there would probably be better, but there
 are nontrivial loading order shenanigans happening that make that not straightforward.
+** TODO buffer switching
+- =SPC b b= should switch workspace after choosing a buffer from a different one
+- universal argument for opening buffer in another window?
 ** TODO Ivy Parity
 *** TODO pass module
-*** TODO remaps
-refactor these to use consult so previews can work, also maybe have narrowed number keys for workspaces?
-#+begin_src elisp
-    [remap switch-to-buffer]              #'+ivy/switch-buffer
-    [remap switch-to-buffer-other-window] #'+ivy/switch-buffer-other-window
-    [remap persp-switch-to-buffer]        #'+ivy/switch-workspace-buffer
-    [remap evil-show-jumps]               #'+ivy/jump-list
-#+end_src
+*** TODO ~+ivy/jump-list~ analogue
 *** TODO ~+irc/selectrum-jump-to-channel~
 rework to use ~consult~ buffer narrowing, for some reason the current attempt breaks marginalia annotating
 *** WAIT lookup module

modules/completion/selectrum/autoload/workspaces.el

@@ -0,0 +1,47 @@
+;;; completion/selectrum/autoload/workspaces.el -*- lexical-binding: t; -*-
+;;;###if (featurep! :ui workspaces)
+
+;;;###autoload
+(defun +selectrum--workspace-nth-source (n)
+  "Generate a consult buffer source for buffers in the NTH workspace"
+  (cond ((numberp n)
+         `(:name     ,(nth (1- n) (+workspace-list-names))
+           :hidden   ,(not (string= (+workspace-current-name) (nth (1- n) (+workspace-list-names))))
+           :narrow   ,(string-to-char (number-to-string n))
+           :category buffer
+           :state    ,#'consult--buffer-state
+           :items    ,(lambda () (mapcar #'buffer-name (+workspace-buffer-list (nth (1- n) (+workspace-list)))))))
+        ((eq n 'final)
+         `(:name     ,(car (last (+workspace-list-names)))
+           :hidden   t
+           :narrow   ?0
+           :category buffer
+           :state    ,#'consult--buffer-state
+           :items    ,(lambda () (mapcar #'buffer-name (+workspace-buffer-list (car (last (+workspace-list))))))))
+        (t
+         (user-error "invalid workspace source %s" n))))
+
+;;;###autoload
+(defun +selectrum--workspace-generate-sources ()
+  "Generate list of consult buffer sources for all workspaces"
+  (mapcar #'+selectrum--workspace-nth-source '(1 2 3 4 5 6 7 8 9 final)))
+
+(autoload 'consult--multi "consult")
+;;;###autoload
+(defun +selectrum/switch-workspace-buffer ()
+  "Switch to another buffer in the same workspace.
+
+Use consult narrowing with another workspace number to open a buffer from that workspace
+ BUG but it opens it in the current workspace (ivy also does this, but who cares)"
+  (interactive)
+  (when-let (buffer (consult--multi (+selectrum--workspace-generate-sources)
+                                    :require-match
+                                    (confirm-nonexistent-file-or-buffer)
+                                    :prompt (format "Switch to buffer (%s): "
+                                                    (+workspace-current-name)
+                                                    :history 'consult--buffer-history
+                                                    :sort nil)))
+    ;; When the buffer does not belong to a source,
+    ;; create a new buffer with the name.
+    (unless (cdr buffer)
+      (funcall consult--buffer-display (car buffer)))))

modules/completion/selectrum/config.el

@@ -91,7 +91,8 @@
     [remap switch-to-buffer-other-window] #'consult-buffer-other-window
     [remap switch-to-buffer-other-frame]  #'consult-buffer-other-frame
     [remap yank-pop]                      #'consult-yank-pop
-    [remap describe-bindings]             #'embark-bindings)
+    [remap describe-bindings]             #'embark-bindings
+    [remap persp-switch-to-buffer]        #'+selectrum/switch-workspace-buffer)
   (setq completion-in-region-function #'consult-completion-in-region)
   :config
   (recentf-mode)