NEATVI
======

Neatvi is a small vi/ex editor for editing UTF-8 text.  It supports
syntax highlighting, multiple windows, right-to-left languages, and
keymaps.

CONFIGURATION
-------------

Edit conf.h to adjust syntax highlighting rules and text direction
patterns.  To define a new keymap, create a new array in kmap.h, like
kmap_fa, and add it to kmaps array in the same header (the first entry
of the new array specifies its name).  The current keymap may be
changed with :cm ex command.  When in input mode, ^e activates the
English keymap and ^f switches to the alternate keymap (the last
keymap specified with :cm).

Sadly, VTE-based terminals such as GNOME's implement a
backward-incompatible extension of virtual terminal escape codes to
render bidirectional text by default.  When using these terminal, the
value of LNPREF macro in conf.h needs to be changed to "\33[8l".

COMMANDS
--------

Commands not available in ex(1):

:cm[ap][!] [kmap]
  Without kmap, prints the current keymap name.
  When kmap is specified, sets the alternate keymap to
  kmap and, unless ! is given, switches to this keymap.
:ft [filetype]
  Without filetype, prints the current file type.
  When filetype is specified, sets the file type of the
  current ex buffer.
:ta[g] tag
  Jumps to tag (tags file: TAGPATH environment variable or ./tags).
:tn[ext]
  Jumps to the next matching tag.
:tp[rev]
  Jumps to the previous matching tag.
:po[p]
  Pops tag stack.
:b[uffer] [buf]
  Without buf, prints buffer list.  Switches to the given buffer
  if buf is a buffer number or alias.  Also, buf can be -, +, !,
  and ~ to switch to the previous buffer, switch to the next buffer,
  delete the current buffer, and renumber buffers, respectively.
:rs reg
  Reads dot-terminated lines (similar to :a command) from ex input
  and copies them to the given yank buffer.
:rx reg cmd
  Like :! command, executes cmd.  However, the contents of the
  specified yank buffer is given to the command as input, and the
  output of the command is written to that yank buffer.
:ec[ho] msg
  Prints the given message (useful in ex scripts or q-commands).

New key mappings:
- ^a in normal mode: searches for the word under the cursor.
- ^p in insert mode: inserts the contents of the default yank buffer.
- ^rX in insert mode: inserts the contents of yank buffer X.
- zL, zl, zr, and zR in normal mode: changes the value of td option.
- ^e and ^f in insert mode: switches to the English and alternate keymap.
- ze and zf in normal mode: switches to the English and alternate keymap.
- gu, gU, and g~ in normal mode: switches character case.
- ^l in normal mode: updates terminal dimensions (after resizing it).
- ^] and ^t in normal mode: jumps to tag and pops tag stack.
- gf in normal mode: edits the file whose address is under the cursor.
- gl in normal mode: like gf, but it reads line and column numbers too.
- ^ws, ^wo, ^wc, ^wj, ^wk, ^wx in normal mode: manages windows.
- ^wgf, ^wgl, ^w^] in normal mode: executes gf, gl, ^] in a new window.
- zj, zk, zD: equivalent to :b+, :b-, :b !.
- zJ, zK: equivalent to :next, :prev.
- q in normal mode: see quick access section.
- ^a in ex, search, and pipe prompts: inserts from history lines.

Other noteworthy differences with vi(1):
- Neatvi assumes POSIX extended regular expressions (ERE) in search
  patterns, conf.h variables, and even tags files.
- If paths start with =, they are assumed to be relative to the
  directory of the current file.
- Neatvi highlights files whose names end with ls as directory
  listings; the gl command edits the file under the cursor.  For
  instance, git ls-files >ls && neatvi ls.
- Neatvi supports extended yank buffers, like \x.

Note that in :rs command, input lines are read from ex input stream
(unlike :a), to make it usable in @ commands and ex scripts (files
passed to :so).  This allows setting the value of yank buffers in ex
files, as the following example shows:

  rs a
  :!git add %
  .

OPTIONS
-------

To improve Neatvi's performance, shaping, character reordering, and
syntax highlighting can be disabled by defining the EXINIT environment
variable as "set noshape | set noorder | set nohl | set td=+2".

Options supported in Neatvi:

td, textdirection
  Current direction context.  The following values are meaningful:
  * +2: always left-to-right.
  * +1: follow conf.h's dircontexts[]; left-to-right for others.
  * -1: follow conf.h's dircontexts[]; right-to-left for others.
  * -2: always right-to-left.
  The default value is 0, which assumes left-to-right if the first
  character of the line is single-byte; otherwise, it follows
  dircontexts[].
shape
  If set, Arabic/Farsi letter shaping will be performed.
order
  If set, characters will be reordered based on the rules defined
  in conf.h.  If the value is 1, only lines with at least one
  multi-byte UTF-8 character are reordered.  If it is 2, all lines
  are reordered.
hl, highlight
  If set, text will be highlighted based on syntax highlighting
  rules in conf.h.
hll, highlightline
  If set, the current line will be highlighted.
lim, linelimit
  Lines longer than this value are not reordered or highlighted.
ru, ruler
  Indicates when to redraw the status line:
  * 0: never.
  * 1: always.
  * 2: when multiple windows are visible.
  * 4: when the current file changes.
hist, history
  Indicates the number of lines remembered for ex, search, and
  pipe prompts.  Zero disables command history.
ai, autoindent
  As in vi(1).
aw, autowrite
  As in vi(1).
ic, ignorecase
  As in vi(1).
wa, writeany
  As in vi(1).

MARKS AND BUFFERS
-----------------

Special marks:
- * the position of the previous change
- [ the first line of the previous change
- ] the last line of the previous change

Special yank buffers:
- / the previous search keyword
- : the previous ex command
- ! the previous pipe command
- % the name of the current file
- " the default yank buffer
- ; the current line
- . the last vi command
- # cursor line number
- ^ cursor line offset
- \/ search history
- \: ex command history
- \! pipe command history

QUICK ACCESS
------------

When q is pressed in normal mode, Neatvi prints the list of buffers at
the bottom of the screen and waits for a key.  If the key is a digit,
it switches to its corresponding buffer.  If it is a letter and the
extended buffer with that letter is defined, the contents of that
buffer is executed.  Otherwise, Neatvi executes ECMD (defined in
conf.h) with the following parameters: i) the letter, ii) the current
file, iii) the current line number, and iv) the current line offset.

What ECMD writes to its standard output, Neatvi executes as ex
commands.  Q-commands can be used to add interesting features to
Neatvi, such as language-dependent IDE features, for instance by
connecting to an LSP (language server protocol) server.  ecmd.sh is an
example ECMD shell script.