1*rileft.txt* For Vim version 7.3. Last change: 2006 Apr 24 2 3 4 VIM REFERENCE MANUAL by Avner Lottem 5 updated by Nadim Shaikli 6 7 8Right to Left display mode for Vim *rileft* 9 10 11These functions were originally created by Avner Lottem: 12 E-mail: alottem@iil.intel.com 13 Phone: +972-4-8307322 14 15{Vi does not have any of these commands} 16 17 *E26* 18{only available when compiled with the |+rightleft| feature} 19 20 21Introduction 22------------ 23Some languages such as Arabic, Farsi, Hebrew (among others) require the 24ability to display their text from right-to-left. Files in those languages 25are stored conventionally and the right-to-left requirement is only a 26function of the display engine (per the Unicode specification). In 27right-to-left oriented files the characters appear on the screen from 28right to left. 29 30Bidirectionality (or bidi for short) is what Unicode offers as a full 31solution to these languages. Bidi offers the user the ability to view 32both right-to-left as well as left-to-right text properly at the same time 33within the same window. Vim currently, due to simplicity, does not offer 34bidi and is merely opting to present a functional means to display/enter/use 35right-to-left languages. An older hybrid solution in which direction is 36encoded for every character (or group of characters) are not supported either 37as this kind of support is out of the scope of a simple addition to an 38existing editor (and it's not sanctioned by Unicode either). 39 40 41Highlights 42---------- 43o Editing left-to-right files as in the original Vim, no change. 44 45o Viewing and editing files in right-to-left windows. File orientation 46 is per window, so it is possible to view the same file in right-to-left 47 and left-to-right modes, simultaneously. (Useful for editing mixed files 48 in which both right-to-left and left-to-right text exist). 49 50o Compatibility to the original Vim. Almost all features work in 51 right-to-left mode (see Bugs below). 52 53o Backing from reverse insert mode to the correct place in the file 54 (if possible). 55 56o No special terminal with right-to-left capabilities is required. The 57 right-to-left changes are completely hardware independent. 58 59o Many languages use and require right-to-left support. These languages 60 can quite easily be supported given the inclusion of their required 61 keyboard mappings and some possible minor code change. Some of the 62 current supported languages include - |arabic.txt|, |farsi.txt| and 63 |hebrew.txt|. 64 65 66Of Interest... 67-------------- 68 69o Invocations 70 ----------- 71 + 'rightleft' ('rl') sets window orientation to right-to-left. 72 + 'delcombine' ('deco'), boolean, if editing UTF-8 encoded languages, 73 allows one to remove a composing character which gets superimposed 74 on those that proceeded them (some languages require this). 75 + 'rightleftcmd' ('rlc') sets the command-line within certain modes 76 (such as search) to be utilized in right-to-left orientation as well. 77 78o Typing backwards *ins-reverse* 79 ---------------- 80 In lieu of using full-fledged the 'rightleft' option, one can opt for 81 reverse insertion. When the 'revins' (reverse insert) option is set, 82 inserting happens backwards. This can be used to type right-to-left 83 text. When inserting characters the cursor is not moved and the text 84 moves rightwards. A <BS> deletes the character under the cursor. 85 CTRL-W and CTRL-U also work in the opposite direction. <BS>, CTRL-W 86 and CTRL-U do not stop at the start of insert or end of line, no matter 87 how the 'backspace' option is set. 88 89 There is no reverse replace mode (yet). 90 91 If the 'showmode' option is set, "-- REVERSE INSERT --" will be shown 92 in the status line when reverse Insert mode is active. 93 94o Pasting when in a rightleft window 95 ---------------------------------- 96 When cutting text with the mouse and pasting it in a rightleft window 97 the text will be reversed, because the characters come from the cut buffer 98 from the left to the right, while inserted in the file from the right to 99 the left. In order to avoid it, toggle 'revins' before pasting. 100 101 102Bugs 103---- 104o Does not handle CTRL-A and CTRL-X commands (add and subtract) correctly 105 when in rightleft window. 106 107o Does not support reverse insert and rightleft modes on the command-line. 108 However, functionality of the editor is not reduced, because it is 109 possible to enter mappings, abbreviations and searches typed from the 110 left to the right on the command-line. 111 112o Somewhat slower in right-to-left mode, because right-to-left motion is 113 emulated inside Vim, not by the controlling terminal. 114 115o When the Athena GUI is used, the bottom scrollbar works in the wrong 116 direction. This is difficult to fix. 117 118o When both 'rightleft' and 'revins' are on: 'textwidth' does not work. 119 Lines do not wrap at all; you just get a single, long line. 120 121o There is no full bidirectionality (bidi) support. 122 123 124 vim:tw=78:ts=8:ft=help:norl: 125