Mercurial > vim
annotate runtime/doc/rileft.txt @ 26985:a770f305b835
Added tag v8.2.4021 for changeset 8dc4782b60ffad5c4d3bc66d01a2b2a3d3a581fa
author | Bram Moolenaar <Bram@vim.org> |
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date | Thu, 06 Jan 2022 22:45:05 +0100 |
parents | 43593a5d873f |
children | 6dd88e45d47d |
rev | line source |
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25056 | 1 *rileft.txt* For Vim version 8.2. Last change: 2021 Jun 13 |
7 | 2 |
3 | |
4 VIM REFERENCE MANUAL by Avner Lottem | |
5 updated by Nadim Shaikli | |
6 | |
7 | |
8 Right to Left display mode for Vim *rileft* | |
9 | |
10 | |
11 These functions were originally created by Avner Lottem: | |
12 E-mail: alottem@iil.intel.com | |
13 Phone: +972-4-8307322 | |
14 | |
15 *E26* | |
2570
71b56b4e7785
Make the references to features in the help more consistent. (Sylvain Hitier)
Bram Moolenaar <bram@vim.org>
parents:
2561
diff
changeset
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16 {only available when compiled with the |+rightleft| feature} |
7 | 17 |
18 | |
19 Introduction | |
20 ------------ | |
21 Some languages such as Arabic, Farsi, Hebrew (among others) require the | |
22 ability to display their text from right-to-left. Files in those languages | |
23 are stored conventionally and the right-to-left requirement is only a | |
24 function of the display engine (per the Unicode specification). In | |
25 right-to-left oriented files the characters appear on the screen from | |
26 right to left. | |
27 | |
28 Bidirectionality (or bidi for short) is what Unicode offers as a full | |
29 solution to these languages. Bidi offers the user the ability to view | |
30 both right-to-left as well as left-to-right text properly at the same time | |
31 within the same window. Vim currently, due to simplicity, does not offer | |
32 bidi and is merely opting to present a functional means to display/enter/use | |
33 right-to-left languages. An older hybrid solution in which direction is | |
34 encoded for every character (or group of characters) are not supported either | |
35 as this kind of support is out of the scope of a simple addition to an | |
236 | 36 existing editor (and it's not sanctioned by Unicode either). |
7 | 37 |
38 | |
39 Highlights | |
40 ---------- | |
41 o Editing left-to-right files as in the original Vim, no change. | |
42 | |
43 o Viewing and editing files in right-to-left windows. File orientation | |
44 is per window, so it is possible to view the same file in right-to-left | |
45 and left-to-right modes, simultaneously. (Useful for editing mixed files | |
46 in which both right-to-left and left-to-right text exist). | |
47 | |
48 o Compatibility to the original Vim. Almost all features work in | |
49 right-to-left mode (see Bugs below). | |
50 | |
51 o Backing from reverse insert mode to the correct place in the file | |
52 (if possible). | |
53 | |
54 o No special terminal with right-to-left capabilities is required. The | |
55 right-to-left changes are completely hardware independent. | |
56 | |
57 o Many languages use and require right-to-left support. These languages | |
58 can quite easily be supported given the inclusion of their required | |
59 keyboard mappings and some possible minor code change. Some of the | |
60 current supported languages include - |arabic.txt|, |farsi.txt| and | |
61 |hebrew.txt|. | |
62 | |
63 | |
64 Of Interest... | |
65 -------------- | |
66 | |
67 o Invocations | |
68 ----------- | |
69 + 'rightleft' ('rl') sets window orientation to right-to-left. | |
70 + 'delcombine' ('deco'), boolean, if editing UTF-8 encoded languages, | |
71 allows one to remove a composing character which gets superimposed | |
21499 | 72 on those that preceded them (some languages require this). |
7 | 73 + 'rightleftcmd' ('rlc') sets the command-line within certain modes |
74 (such as search) to be utilized in right-to-left orientation as well. | |
75 | |
76 o Typing backwards *ins-reverse* | |
77 ---------------- | |
25056 | 78 In lieu of using the full-fledged 'rightleft' option, one can opt for |
7 | 79 reverse insertion. When the 'revins' (reverse insert) option is set, |
80 inserting happens backwards. This can be used to type right-to-left | |
81 text. When inserting characters the cursor is not moved and the text | |
82 moves rightwards. A <BS> deletes the character under the cursor. | |
83 CTRL-W and CTRL-U also work in the opposite direction. <BS>, CTRL-W | |
84 and CTRL-U do not stop at the start of insert or end of line, no matter | |
85 how the 'backspace' option is set. | |
86 | |
87 There is no reverse replace mode (yet). | |
88 | |
89 If the 'showmode' option is set, "-- REVERSE INSERT --" will be shown | |
90 in the status line when reverse Insert mode is active. | |
91 | |
92 o Pasting when in a rightleft window | |
93 ---------------------------------- | |
94 When cutting text with the mouse and pasting it in a rightleft window | |
95 the text will be reversed, because the characters come from the cut buffer | |
96 from the left to the right, while inserted in the file from the right to | |
97 the left. In order to avoid it, toggle 'revins' before pasting. | |
98 | |
99 | |
100 Bugs | |
101 ---- | |
102 o Does not handle CTRL-A and CTRL-X commands (add and subtract) correctly | |
103 when in rightleft window. | |
104 | |
105 o Does not support reverse insert and rightleft modes on the command-line. | |
106 However, functionality of the editor is not reduced, because it is | |
107 possible to enter mappings, abbreviations and searches typed from the | |
108 left to the right on the command-line. | |
109 | |
110 o Somewhat slower in right-to-left mode, because right-to-left motion is | |
111 emulated inside Vim, not by the controlling terminal. | |
112 | |
113 o When the Athena GUI is used, the bottom scrollbar works in the wrong | |
114 direction. This is difficult to fix. | |
115 | |
116 o When both 'rightleft' and 'revins' are on: 'textwidth' does not work. | |
117 Lines do not wrap at all; you just get a single, long line. | |
118 | |
119 o There is no full bidirectionality (bidi) support. | |
120 | |
121 | |
14421 | 122 vim:tw=78:ts=8:noet:ft=help:norl: |