1 files changed, 44 insertions, 0 deletions
diff --git a/modules/system-lib.el b/modules/system-lib.el
index 49bb6cd1a..f1049c021 100644
--- a/modules/system-lib.el
+++ b/modules/system-lib.el
@@ -164,6 +164,50 @@ contributes its own modes regardless of load order."
     (setq font-lock-global-modes
           (cj/--font-lock-global-modes-excluding font-lock-global-modes mode))))
 
+(defun cj/completion-table (category collection)
+  "Return a completion table over COLLECTION tagged with completion CATEGORY.
+COLLECTION is anything `completing-read' accepts (list, alist, obarray, hash
+table, or another table).  The table reports CATEGORY in its metadata so
+marginalia (and embark, consult, sorting) can recognize and annotate the
+candidates.  Use a standard category (file, buffer, function, theme, ...) when
+the candidates match one; marginalia then annotates them with no further work."
+  (lambda (string predicate action)
+    (if (eq action 'metadata)
+        `(metadata (category . ,category))
+      (complete-with-action action collection string predicate))))
+
+(defun cj/completion-table-annotated (category annotate collection)
+  "Like `cj/completion-table' but also attach ANNOTATE as the annotation function.
+ANNOTATE is called with a candidate string and returns its annotation suffix, or
+nil.  Use this for a custom CATEGORY that marginalia has no built-in annotator
+for: marginalia falls back to the table's own annotation function."
+  (lambda (string predicate action)
+    (if (eq action 'metadata)
+        `(metadata (category . ,category)
+                   (annotation-function . ,annotate))
+      (complete-with-action action collection string predicate))))
+
+(defun cj/completion-file-annotator (candidate->path)
+  "Return an annotation function for completion candidates backed by files.
+CANDIDATE->PATH maps a candidate string to its absolute file path, or nil when
+the candidate has no backing file.  The returned function, suitable as a
+completion table's annotation function (see `cj/completion-table-annotated'),
+yields a suffix with the file size and modification date for a regular file,
+the marker \"dir\" plus the date for a directory, or nil when the path is nil
+or the file is missing -- so marginalia then shows no suffix for that
+candidate."
+  (lambda (cand)
+    (let ((path (funcall candidate->path cand)))
+      (when (and path (file-exists-p path))
+        (let* ((attrs (file-attributes path))
+               (dirp  (eq t (file-attribute-type attrs)))
+               (size  (if dirp "dir"
+                        (file-size-human-readable (file-attribute-size attrs))))
+               (date  (format-time-string
+                       "%Y-%m-%d"
+                       (file-attribute-modification-time attrs))))
+          (format "  %8s  %s" size date))))))
+
 (defun cj/format-region-with-program (program &rest args)
   "Replace the current buffer with PROGRAM ARGS run over its contents, via argv.
 Runs PROGRAM (with ARGS) on the whole buffer through `call-process-region'