Introduction

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 intension 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.

Highlights

• Editing left-to-right files as in the original Vim, no change.
• 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.)
• Compatibility to the original Vim. Almost all features work in right-to-left mode (see Bugs below).
• Changing keyboard mapping and reverse insert modes using a single command.
• Backing from reverse insert mode to the correct place in the file (if possible).
• No special terminal with right-to-left capabilities is required. The right-to-left changes are completely hardware independent. Only Hebrew font is necessary.
• ALL enhancements depend on a compilation variable, RIGHTLEFT, so it is possible to compile Vim without this support.
• 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

• Variables:
  • 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.
• 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 overided using the aleph variable.

• Command line switches:
  • 'vim -H file' starts editing a Hebrew file, i.e. rightleft and hkmap are set.

• Keyboard:
  • CTRL-_ in insert/replace modes toggles revins and hkmap as follows:

    When in rightleft window, revins+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, unlike CTRL-B that leaves the cursor in the same place.

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

Bugs

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

• 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.

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

• 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.

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.

In Insert mode the 'revins' option can be toggled with CTRL-B.

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.

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).