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emacs/test/manual/biditest.el
2021-09-26 17:53:23 +02:00

126 lines
4.5 KiB
EmacsLisp

;;; biditest.el --- test bidi reordering in GNU Emacs display engine. -*- lexical-binding: t; -*-
;; Copyright (C) 2013-2021 Free Software Foundation, Inc.
;; Author: Eli Zaretskii
;; Maintainer: emacs-devel@gnu.org
;; Package: emacs
;; This file is part of GNU Emacs.
;; GNU Emacs 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.
;; GNU Emacs 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 GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
;;; Commentary:
;; Produce a specially-formatted text file from BidiCharacterTest.txt
;; file that is part of the Unicode Standard's UCD package. The file
;; shows the expected results of reordering according to the UBA. The
;; file is supposed to be visited in Emacs, and the resulting display
;; compared with the expected one.
;;; Code:
(defun biditest-generate-testfile (input-file output-file)
"Generate a bidi test file OUTPUT-FILE from data in INPUT-FILE.
INPUT-FILE should be in the format of the BidiCharacterTest.txt file
available from the Unicode site, as part of the UCD database, see
https://www.unicode.org/Public/UCD/latest/ucd/BidiCharacterTest.txt.
The resulting file should be viewed with `inhibit-bidi-mirroring' set to t."
(let ((output-buf (get-buffer-create "*biditest-output*"))
(lnum 1)
tbuf)
(with-temp-buffer
(message "Generating output in %s ..." output-file)
(setq tbuf (current-buffer))
(insert-file-contents input-file)
(goto-char (point-min))
(while (not (eobp))
(when (looking-at "^\\([0-9A-F ]+\\);\\([012]\\);\\([01]\\);\\([0-9x ]+\\);\\([0-9 ]+\\)$")
(let ((codes (match-string 1))
(default-paragraph (match-string 2))
(resolved-paragraph (match-string 3))
;; FIXME: Should compare LEVELS with what the display
;; engine actually produced.
;;(levels (match-string 4))
(indices (match-string 5)))
(setq codes (split-string codes " ")
indices (split-string indices " "))
(switch-to-buffer output-buf)
(insert (format "Test on line %d:\n\n" lnum))
;; Force paragraph direction to what the UCD test
;; specifies.
(insert (cond
((string= default-paragraph "0") ;L2R
#x200e)
((string= default-paragraph "1") ;R2L
#x200f)
(t ""))) ; dynamic
;; Insert the characters
(mapc (lambda (code)
(insert (string-to-number code 16)))
codes)
(insert "\n\n")
;; Insert the expected results
(insert "Expected result:\n\n")
;; We want the expected results displayed exactly as
;; specified in the test file, without any reordering, so
;; we override the directional properties of all of the
;; characters in the expected result by prepending
;; LRO/RLO.
(cond ((string= resolved-paragraph "0")
(insert #x200e #x202d))
((string= resolved-paragraph "1")
(insert #x200f #x202e)
;; We need to reverse the list of indices for R2L
;; paragraphs, so that their logical order on
;; display matches user expectations.
(setq indices (nreverse indices))))
(mapc (lambda (index)
(insert (string-to-number
(nth (string-to-number index 10) codes)
16)))
indices)
(insert #x202c) ; end the embedding
(insert "\n\n"))
(switch-to-buffer tbuf))
(forward-line 1)
(setq lnum (1+ lnum)))
(switch-to-buffer output-buf)
(let ((coding-system-for-write 'utf-8-unix))
(write-file output-file))
(message "Generating output in %s ... done" output-file))))
(defun biditest-create-test ()
"Create a test file for testing the Emacs bidirectional display.
The resulting file should be viewed with `inhibit-bidi-mirroring' set to t."
(biditest-generate-testfile (pop command-line-args-left)
(or (pop command-line-args-left)
"biditest.txt")))
;; A handy function for displaying the resolved bidi levels.
(defun bidi-levels ()
"Display the resolved bidirectional levels of characters on current line.
The results can be compared with the levels stated in the
BidiCharacterTest.txt file."
(interactive)
(message "%s" (bidi-resolved-levels)))
(define-key global-map [f8] #'bidi-levels)
;;; biditest.el ends here