selectrum: improve SPC b b

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

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)))))