Re: sort-lines including non ASCII

[Michael Heerdegen <michael_heerdegen@web.de>]

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Eli Zaretskii <eliz@gnu.org> writes:

> > BTW, a relevant question is: Is `compare-buffer-substring' faster than
> > `buffer-substring'+`string<'?
>
> Hard to say.  Measuring is the easiest way to answer that.

Here is a first try.  The speed difference is negligible here.


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From 6229d19438d641d3ec81dec962984b3a9f5f72e7 Mon Sep 17 00:00:00 2001
From: Michael Heerdegen <michael_heerdegen@web.de>
Date: Fri, 8 Jul 2016 00:46:20 +0200
Subject: [PATCH] Make sort-lines accept a predicate

---
 lisp/sort.el | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/lisp/sort.el b/lisp/sort.el
index 4d7311f..266b916 100644
--- a/lisp/sort.el
+++ b/lisp/sort.el
@@ -1,4 +1,4 @@
-;;; sort.el --- commands to sort text in an Emacs buffer
+;;; sort.el --- commands to sort text in an Emacs buffer  -*- lexical-binding : t -*-
 
 ;; Copyright (C) 1986-1987, 1994-1995, 2001-2016 Free Software
 ;; Foundation, Inc.
@@ -99,7 +99,7 @@ sort-subr
 	  (setq sort-lists
 		(sort sort-lists
 		      (cond (predicate
-			     `(lambda (a b) (,predicate (car a) (car b))))
+			     (lambda (a b) (funcall predicate (car a) (car b))))
 			    ((numberp (car (car sort-lists)))
 			     'car-less-than-car)
 			    ((consp (car (car sort-lists)))
@@ -197,7 +197,7 @@ sort-reorder-buffer
 	(delete-region max (1+ max))))))
 
 ;;;###autoload
-(defun sort-lines (reverse beg end)
+(defun sort-lines (reverse beg end &optional predicate)
   "Sort lines in region alphabetically; argument means descending order.
 Called from a program, there are three arguments:
 REVERSE (non-nil means reverse order), BEG and END (region to sort).
@@ -210,7 +210,13 @@ sort-lines
       (goto-char (point-min))
       (let ;; To make `end-of-line' and etc. to ignore fields.
 	  ((inhibit-field-text-motion t))
-	(sort-subr reverse 'forward-line 'end-of-line)))))
+	(sort-subr
+         reverse #'forward-line #'end-of-line nil nil
+         (and predicate
+              (lambda (a b)
+                (funcall predicate
+                         (buffer-substring (car a) (cdr a))
+                         (buffer-substring (car b) (cdr b))))))))))
 
 ;;;###autoload
 (defun sort-paragraphs (reverse beg end)
-- 
2.8.1


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I had to convert the file to lexical binding to avoid a quoted lambda,
or else we had been forbidden to name the optional argument "predicate"
(variable name clash).

> My opinion is the opposite: I think it's more important to have a
> command that could collate-order strings according to a user-specified
> locale, than make sort-lines more flexible on the Lisp level.

What would you do?  Just create an additional command?


Michael.