neovim/runtime/doc/farsi.txt

*farsi.txt*     Nvim


		  VIM REFERENCE MANUAL    by Mortaza Ghassab Shiran


Right to Left and Farsi Mapping for Vim		*farsi* *Farsi*

These functions have been made by Mortaza G. Shiran <shiran@jps.net>


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 Farsi documents,
composing faxes or writing Farsi memos.

The commands, prompts and help files are not in Farsi, therefore the user
interface remains the standard Vi interface.


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.

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  While in Farsi mode, numbers are entered from left to right.  Upon entering
   a none number character, that character will be inserted just into the
   left of the last number.

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

o  Farsi keymapping on the command line in reverse insert mode.

o  Toggling between left-to-right and right-to-left via F8 function key.

o  Toggling between Farsi ISIR-3342 standard encoding and Vim Farsi via F9
   function key.  Since this makes sense only for the text written in
   right-to-left mode, this function is also supported only in right-to-left
   mode.


Usage
-----
Prior to starting Vim, the environment in which Vim can run in Farsi mode,
must be set.  In addition to installation of Farsi fonts, following points
refer to some of the system environments, which you may need to set:
Key code mapping, loading graphic card in ASCII screen mode, setting the IO
driver in 8 bit clean mode ... .

o  Setting the Farsi fonts

   +  For Vim GUI set the 'guifont' to far-a01.  This is done by entering
      ':set guifont=far-a01' in the Vim window.

      You can have 'guifont' set to far-a01 by Vim during the Vim startup
      by appending the ':set guifont=far-a01' into your vimrc file.

      Under the X Window environment, you can also start Vim with the
      '-fn far-a01' option.

   +  For Vim within a xterm, start a xterm with the Farsi fonts (e.g.
      kterm -fn far-a01).  Then start Vim inside the kterm.

   +  For Vim under DOS, prior to the first usage of Vim, upload the Farsi
      fonts by executing the far-a01.com fonts uploading program.

o  Farsi Keymapping Activation

   To activate the Farsi keymapping, set either 'altkeymap' or 'fkmap'.
   This is done by entering ':set akm' or ':set fk' in the Vim window.
   You can have 'altkeymap' or 'fkmap' set as default by appending ':set akm'
   or ':set fk' in your vimrc file.

   To turn off the Farsi keymapping as a default second language keymapping,
   reset the 'altkeymap' by entering ':set noakm'.

o  right-to-left Farsi Mode

   By default Vim starts in Left-to-right mode.  Following are ways to change
   the window orientation:

   + Start Vim with the -F option (e.g. vim -F ...).

   + Use the F8 function key to toggle between left-to-right and right-to-left.

   + While in Left-to-right mode, enter 'set rl' in the command line ('rl' is
     the abbreviation for rightleft).

   + Put the 'set rl' line in your vimrc file to start Vim in right-to-left 
     mode permanently.

Encoding
--------

The letter encoding used is the Vim extended ISIR-3342 standard with a built
in function to convert between Vim extended ISIR-3342 and ISIR-3342 standard.

For document portability reasons, the letter encoding is kept the same across
different platforms (i.e. Unix, Windows, ...).


o  Keyboard

   +  CTRL-_ in insert/replace modes toggles between Farsi(akm)/Latin
      mode as follows:

   +  CTRL-_ moves the cursor to the end of the typed text in edit mode.

   +  CTRL-_ in command mode only toggles keyboard mapping between Farsi(akm)/
      Latin.  The Farsi text is then entered in reverse insert mode.

   +  F8 - Toggles between left-to-right and right-to-left.

   +  F9 - Toggles the encoding between ISIR-3342 standard and Vim extended
      ISIR-3342 (supported only in right-to-left mode).

   +  Keyboard mapping is based on the Iranian ISIRI-2901 standard.
      Following table shows the keyboard mapping while Farsi(akm) mode set:

	-------------------------------------
	`  1  2  3  4  5  6  7  8  9  0  -  =
	<09>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>
	-------------------------------------
	~  !  @  #  $  %  ^  &  *  (  )  _  +
	~  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>
	-------------------------------------
	q  w  e  r  t  z  u  i  o  p  [  ]
	<09>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>
	-------------------------------------
	Q  W  E  R  T  Z  U  I  O  P  {  }
	<09>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  [  ]  {  }
	-------------------------------------
	a  s  d  f  g  h  j  k  l  ;  '  \
	<09>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>
	-------------------------------------
	A  S  D  F  G  H  J  K  L  :  "  |
	<09>  <20><> <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>
	-------------------------------------
	<  y  x  c  v  b  n  m  ,  .  /
	<09>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>
	-------------------------------------
	>  Y  X  C  V  B  N  M  <  >  ?
	<09>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>  <20>
	-------------------------------------

Note:
	<09>  stands for Farsi PSP (break without space)

	<09>  stands for Farsi PCN (for HAMZE attribute)

Restrictions
------------

o  In insert/replace mode and fkmap (Farsi mode) set, CTRL-B is not
   supported.

o  If you change the character mapping between Latin/Farsi, the redo buffer
   will be reset (emptied).  That is, redo is valid and will function (using
   '.') only within the mode you are in.

o  While numbers are entered in Farsi mode, the redo buffer will be reset
   (emptied).  That is, you cannot redo the last changes (using '.') after
   entering numbers.

o  While in left-to-right mode and Farsi mode set, CTRL-R is not supported.

o  While in right-to-left mode, the search on 'Latin' pattern does not work,
   except if you enter the Latin search pattern in reverse.

o  In command mode there is no support for entering numbers from left
   to right and also for the sake of flexibility the keymapping logic is
   restricted.

o  Under the X Window environment, if you want to run Vim within a xterm
   terminal emulator and Farsi mode set, you need to have an ANSI compatible
   xterm terminal emulator.  This is because the letter codes above 128 decimal
   have certain meanings in the standard xterm terminal emulator.

   Note: Under X Window environment, Vim GUI works fine in Farsi mode.
	 This eliminates the need of any xterm terminal emulator.


Bugs
----
While in insert/replace and Farsi mode set, if you repeatedly change the
cursor position (via cursor movement) and enter new text and then try to undo
the last change, the undo will lag one change behind.  But as you continue to
undo, you will reach the original line of text.  You can also use U to undo all
changes made in the current line.

For more information about the bugs refer to rileft.txt.

 vim:tw=78:ts=8:ft=help:norl: