# Vim documentation: rightleft

main help file

    *rightleft.txt* For Vim version 6.0at.  Last change: 2001 May 12

    		  VIM REFERENCE MANUAL    by Avner Lottem

    Right to Left and Hebrew Mapping for Vim		*hebrew*

    These functions have been made by Avner Lottem
    E-mail: <alottem@iil.intel.com>
    Phone:  +972-4-8307322

    {Vi does not have any of these commands}

    							*E26*
    All this is only available when the |+rightleft| feature was enabled at
    compile time.

    Introduction
    In right-to-left oriented files the characters appear on the screen from right
    to left.  This kind of file is most useful when writing Hebrew documents using
    TeX--XeT, troffh, composing faxes or writing Hebrew memos.

    Logical order files, where direction is encoded for every character (or group
    of characters) are not supported as this kind of support is out of the scope
    of a simple addition to an existing editor.  Also, no Hebrew commands, prompts
    and help files were added, the standard Vi interface was maintained.  The
    intention here was to incorporate Hebrew support to an existing modern and
    live editor, hoping that the Hebrew support will continue to live in
    subsequent versions.  Many other Hebrew supported packages were designed for a
    particular version of the original (English) software and when it continued
    developing, the Hebrew version stayed behind.  Therefore this particular
    support to Vim tries to be as simple (and short) as possible, so that it could
    be incorporated into the official source.

    Note that most of the other documentation files ignore rightleft mode and talk
    about movement and character positions as if there was no rightleft mode.

    Highlights
    o  Editing left-to-right files as in the original Vim, no change.

    o  Viewing and editing files in right-to-left windows.   File orientation
       is per window, so it is possible to view the same file in right-to-left
       and left-to-right modes, simultaneously.
       (This is sometimes useful when editing documents with TeX--XeT.)

    o  Compatibility to the original Vim.   Almost all features work in
       right-to-left mode (see Bugs below).

    o  Changing keyboard mapping and reverse insert modes using a single
       command.

    o  Backing from reverse insert mode to the correct place in the file
       (if possible).

    o  No special terminal with right-to-left capabilities is required.  The
       right-to-left changes are completely hardware independent.  Only
       Hebrew font is necessary.

       The MIT X distribution includes at least two fonts: heb6x13 and heb8x13.
       Some fonts are on
    	http://sunsite.unc.edu/pub/Linux/X11/fonts/hebxfonts-0.2.tgz
       More pointers are in the Hebrew HOWTO on
    	http://sunsite.unc.edu/pub/Linux/docs/HOWTO
       To create a Hebrew font for a DOS box under MS-Windows, refer to a hack on
    	ftp://tochna.technion.ac.il/pub/staff/lottem/doswin-0.1.tgz.

    o  It should be quite easy to adjust this support to handle other right-to
       left languages, such as Arabic, by simply changing the keyboard mapping
       according to the character encoding.

    Change details
    +  Options:
       +  'rightleft' ('rl') sets window orientation to right-to-left.
       +  'hkmap' ('hk') sets keyboard mapping to Hebrew, in insert/replace modes.
       +  'aleph' ('al'), numeric, holds the decimal code of Aleph, for keyboard
          mapping.
       +  'delcombine' ('deco'), boolean, if editing UTF-8 encoded Hebrew, allows
          one to remove the niqud by pressing 'x' on a character (with associated
          niqud).

    +  Encoding:
       +  Under Unix, ISO 8859-8 encoding (Hebrew letters codes: 224-250).
       +  Under MS DOS, PC encoding (Hebrew letters codes: 128-154).
       These are defaults, that can be overridden using the 'aleph' option.

    +  Vim arguments:
       +  'vim -H file' starts editing a Hebrew file, i.e. 'rightleft' and 'hkmap'
          are set.

    +  Keyboard:
       +  The 'allowrevins' option enables the CTRL-_ command in Insert mode and
          in Command-line mode.

       +  CTRL-_ in insert/replace modes toggles 'revins' and 'hkmap' as follows:

          When in rightleft window, 'revins' and 'nohkmap' are toggled, since
          English will likely be inserted in this case.

          When in norightleft window, 'revins' 'hkmap' are toggled, since Hebrew
          will likely be inserted in this case.

          CTRL-_ moves the cursor to the end of the typed text.

       +  CTRL-_ in command mode only toggles keyboard mapping (see Bugs below).
          This setting is independent of 'hkmap' option, which only applies to
          insert/replace mode.

          Note: On some keyboards, CTRL-_ is mapped to CTRL-?.

       +  Keyboard mapping while 'hkmap' is set:

    	q w e r t y u i o p		The characters in the mapping shown
    	/ '' ÷ ø à è å ï í ô		here are for ISO 8859-8.

    	 a s d f g h j k l ; ''
    	 ù ã â ë ò é ç ì ê ó ,

    	  z x c v b n m , . /
    	  æ ñ á ä ð î ö ú õ .

    Bugs
    o  Does not handle CTRL-A and CTRL-X commands (add and subtract)
       correctly when in rightleft window.

    o  Does not support reverse insert and rightleft modes on the command-line.
       However, functionality of the editor is not reduced, because it is
       possible to enter mappings, abbreviations and searches with Hebrew text,
       typed from the left to the right on the command-line.

    o  Somewhat slower in right-to-left mode, because right-to-left motion is
       emulated inside Vim, not by the controlling terminal.

    o  Does not support 7 bit terminals.  Only a terminal with complete
       Hebrew English font (without need to send escape sequences to switch
       between Hebrew and English) is supported.

    o  When the Athena GUI is used, the bottom scrollbar works in the wrong
       direction.  This is difficult to fix.

    o  When both 'rightleft' and 'revins' are on: 'textwidth' does not work.
       Lines do not wrap at all; you just get a single, long line.

    Typing backwards					*ins-reverse*

    If the 'revins' (reverse insert) option is set, inserting happens backwards.
    This can be used to type Hebrew.  When inserting characters the cursor is not
    moved and the text moves rightwards.  A <BS> deletes the character under the
    cursor.  CTRL-W and CTRL-U also work in the opposite direction.  <BS>, CTRL-W
    and CTRL-U do not stop at the start of insert or end of line, no matter how
    the 'backspace' option is set.

    There is no reverse replace mode (yet).

    If the 'showmode' option is set, "-- REVERSE INSERT --" will be shown in the
    status line when reverse Insert mode is active.

    When the 'allowrevins' option is set, reverse Insert mode can be also entered
    via CTRL-_, which has some extra functionality: First, keyboard mapping is
    changed according to the window orientation -- if in a left-to-right window,
    'revins' is used to enter Hebrew text, so the keyboard changes to Hebrew
    ('hkmap' is set); if in a right-to-left window, 'revins' is used to enter
    English text, so the keyboard changes to English ('hkmap' is reset).  Second,
    when exiting 'revins' via CTRL-_, the cursor moves to the end of the typed
    text (if possible).

    Pasting when in a rightleft window

    When cutting text with the mouse and pasting it in a rightleft window
    the text will be reversed, because the characters come from the cut buffer
    from the left to the right, while inserted in the file from the right to
    the left.   In order to avoid it, toggle 'revins' (by typing CTRL-? or CTRL-_)
    before pasting.

    Hebrew characters and the 'isprint' variable

    Sometimes Hebrew character codes are in the none-printable range defined by
    the 'isprint' variable.  For example in the Linux console, the Hebrew font
    encoding starts from 128, while the default 'isprint' variable is @,161-255.
    The result is that all Hebrew characters are displayed as ~x.  To solve this
    problem, set isprint=@,128-255.

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