rileft.txt (5141B)
1 *rileft.txt* Nvim 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 ------------------------------------------------------------------------------ 16 Introduction 17 18 Some languages such as Arabic, Farsi, Hebrew (among others) require the 19 ability to display their text from right-to-left. Files in those languages 20 are stored conventionally and the right-to-left requirement is only a 21 function of the display engine (per the Unicode specification). In 22 right-to-left oriented files the characters appear on the screen from 23 right to left. 24 25 Bidirectionality (or bidi for short) is what Unicode offers as a full 26 solution to these languages. Bidi offers the user the ability to view 27 both right-to-left as well as left-to-right text properly at the same time 28 within the same window. Vim currently, due to simplicity, does not offer 29 bidi and is merely opting to present a functional means to display/enter/use 30 right-to-left languages. An older hybrid solution in which direction is 31 encoded for every character (or group of characters) are not supported either 32 as this kind of support is out of the scope of a simple addition to an 33 existing editor (and it's not sanctioned by Unicode either). 34 35 As many people working on the code do not use the right-to-left mode, this 36 feature may not work in some situations. If you can describe what is wrong 37 and how it would work when fixed, please create an issue on github, see 38 |bug-report|. 39 40 41 ------------------------------------------------------------------------------ 42 Highlights 43 44 o Editing left-to-right files as in the original Vim, no change. 45 46 o Viewing and editing files in right-to-left windows. File orientation 47 is per window, so it is possible to view the same file in right-to-left 48 and left-to-right modes, simultaneously. (Useful for editing mixed files 49 in which both right-to-left and left-to-right text exist). 50 51 o Compatibility to the original Vim. Almost all features work in 52 right-to-left mode (see Bugs below). 53 54 o Backing from reverse insert mode to the correct place in the file 55 (if possible). 56 57 o No special terminal with right-to-left capabilities is required. The 58 right-to-left changes are completely hardware independent. 59 60 o Many languages use and require right-to-left support. These languages 61 can quite easily be supported given the inclusion of their required 62 keyboard mappings and some possible minor code change. Some of the 63 current supported languages include - |l10n-arabic.txt| and |l10n-hebrew.txt|. 64 65 66 ------------------------------------------------------------------------------ 67 Of Interest... 68 69 o 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 preceded 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 78 o Typing backwards *ins-reverse* 79 80 In lieu of using the full-fledged '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 94 o 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. 100 101 102 ------------------------------------------------------------------------------ 103 Bugs 104 105 o Does not handle CTRL-A and CTRL-X commands (add and subtract) correctly 106 when in rightleft window. 107 108 o Does not support reverse insert and rightleft modes on the command-line. 109 However, functionality of the editor is not reduced, because it is 110 possible to enter mappings, abbreviations and searches typed from the 111 left to the right on the command-line. 112 113 o Somewhat slower in right-to-left mode, because right-to-left motion is 114 emulated inside Vim, not by the controlling terminal. 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. 120 121 122 vim:tw=78:ts=8:noet:ft=help:norl: