Add corfu-history and corfu-info extensionsextensions

1 files changed, 101 insertions, 0 deletions

diff --git a/extensions/corfu-history.el b/extensions/corfu-history.el
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+;;; corfu-history.el --- Sorting by history for Corfu -*- lexical-binding: t -*-
+
+;; Copyright (C) 2022  Free Software Foundation, Inc.
+
+;; Author: Daniel Mendler <mail@daniel-mendler.de>
+;; Maintainer: Daniel Mendler <mail@daniel-mendler.de>
+;; Created: 2021
+;; Version: 0.1
+;; Package-Requires: ((emacs "27.1") (corfu "0.20"))
+;; Homepage: https://github.com/minad/corfu
+
+;; This file is part of GNU Emacs.
+
+;; This program is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; Sort candidates by their history position. Maintain a list of
+;; recently selected candidates.
+
+;;; Code:
+
+(require 'corfu)
+
+(defcustom corfu-history-length nil
+  "Corfu history length."
+  :type '(choice (const nil) integer)
+  :group 'corfu)
+
+(defvar corfu-history--hash nil
+  "Hash table of Corfu candidates.")
+
+(defvar corfu-history nil
+  "History of Corfu candidates.")
+
+(defun corfu-history--sort-predicate (x y)
+  "Sorting predicate which compares X and Y."
+  (or (< (cdr x) (cdr y))
+      (and (= (cdr x) (cdr y))
+           (string< (car x) (car y)))))
+
+(defun corfu-history--sort (candidates)
+  "Sort CANDIDATES by history."
+  (unless corfu-history--hash
+    (let ((index 0))
+      (setq corfu-history--hash (make-hash-table :test #'equal :size (length corfu-history)))
+      (dolist (elt corfu-history)
+        (unless (gethash elt corfu-history--hash)
+          (puthash elt index corfu-history--hash))
+        (setq index (1+ index)))))
+  ;; Decorate each candidate with (index<<13) + length. This way we sort first by index and then by
+  ;; length. We assume that the candidates are shorter than 2**13 characters and that the history is
+  ;; shorter than 2**16 entries.
+  (let ((cand candidates))
+    (while cand
+      (setcar cand (cons (car cand)
+                         (+ (lsh (gethash (car cand) corfu-history--hash #xFFFF) 13)
+                            (length (car cand)))))
+      (pop cand)))
+  (setq candidates (sort candidates #'corfu-history--sort-predicate))
+  ;; Drop decoration from the candidates
+  (let ((cand candidates))
+    (while cand
+      (setcar cand (caar cand))
+      (pop cand)))
+  candidates)
+
+(defun corfu-history--insert (&rest _)
+  "Advice for `corfu--insert'."
+  (when (>= corfu--index 0)
+    (add-to-history 'corfu-history
+                    (nth corfu--index corfu--candidates)
+                    corfu-history-length)
+    (setq corfu-history--hash nil)))
+
+;;;###autoload
+(define-minor-mode corfu-history-mode
+  "Update Corfu history and sort completions by history."
+  :global t
+  :group 'corfu
+  (cond
+   (corfu-history-mode
+    (setq corfu-sort-function #'corfu-history--sort)
+    (advice-add #'corfu--insert :before #'corfu-history--insert))
+   (t
+    (setq corfu-sort-function #'corfu-sort-length-alpha)
+    (advice-remove #'corfu--insert #'corfu-history--insert))))
+
+(provide 'corfu-history)
+;;; corfu-history.el ends here