" Vim script to work like "less"
" Maintainer: Bram Moolenaar <[email protected]>
" Last Change: 2012 May 18

" Avoid loading this file twice, allow the user to define his own script.
if exists("loaded_less")
finish
endif
let loaded_less = 1

" If not reading from stdin, skip files that can't be read.
" Exit if there is no file at all.
if argc() > 0
let s:i = 0
while 1
if filereadable(argv(s:i))
if s:i != 0
sleep 3
endif
break
endif
if isdirectory(argv(s:i))
echomsg "Skipping directory " . argv(s:i)
elseif getftime(argv(s:i)) < 0
echomsg "Skipping non-existing file " . argv(s:i)
else
echomsg "Skipping unreadable file " . argv(s:i)
endif
echo "\n"
let s:i = s:i + 1
if s:i == argc()
quit
endif
next
endwhile
endif

set nocp
syntax on
set so=0
set hlsearch
set incsearch
nohlsearch
" Don't remember file names and positions
set viminfo=
set nows
" Inhibit screen updates while searching
let s:lz = &lz
set lz

" Used after each command: put cursor at end and display position
if &wrap
noremap <SID>L L0:redraw<CR>:file<CR>
au VimEnter * normal! L0
else
noremap <SID>L Lg0:redraw<CR>:file<CR>
au VimEnter * normal! Lg0
endif

" When reading from stdin don't consider the file modified.
au VimEnter * set nomod

" Can't modify the text
set noma

" Give help
noremap h :call <SID>Help()<CR>
map H h
fun! s:Help()
echo "<Space> One page forward b One page backward"
echo "d Half a page forward u Half a page backward"
echo "<Enter> One line forward k One line backward"
echo "G End of file g Start of file"
echo "N% percentage in file"
echo "\n"
echo "/pattern Search for pattern ?pattern Search backward for pattern"
echo "n next pattern match N Previous pattern match"
echo "\n"
echo ":n<Enter> Next file :p<Enter> Previous file"
echo "\n"
echo "q Quit v Edit file"
let i = input("Hit Enter to continue")
endfun

" Scroll one page forward
noremap <script> <Space> :call <SID>NextPage()<CR><SID>L
map <C-V> <Space>
map f <Space>
map <C-F> <Space>
map z <Space>
map <Esc><Space> <Space>
fun! s:NextPage()
if line(".") == line("$")
if argidx() + 1 >= argc()
" Don't quit at the end of the last file
return
endif
next
1
else
exe "normal! \<C-F>"
endif
endfun

" Re-read file and page forward "tail -f"
map F :e<CR>G<SID>L:sleep 1<CR>F

" Scroll half a page forward
noremap <script> d <C-D><SID>L
map <C-D> d

" Scroll one line forward
noremap <script> <CR> <C-E><SID>L
map <C-N> <CR>
map e <CR>
map <C-E> <CR>
map j <CR>
map <C-J> <CR>

" Scroll one page backward
noremap <script> b <C-B><SID>L
map <C-B> b
map w b
map <Esc>v b

" Scroll half a page backward
noremap <script> u <C-U><SID>L
noremap <script> <C-U> <C-U><SID>L

" Scroll one line backward
noremap <script> k <C-Y><SID>L
map y k
map <C-Y> k
map <C-P> k
map <C-K> k

" Redraw
noremap <script> r <C-L><SID>L
noremap <script> <C-R> <C-L><SID>L
noremap <script> R <C-L><SID>L

" Start of file
noremap <script> g gg<SID>L
map < g
map <Esc>< g

" End of file
noremap <script> G G<SID>L
map > G
map <Esc>> G

" Go to percentage
noremap <script> % %<SID>L
map p %

" Search
noremap <script> / H$:call <SID>Forward()<CR>/
if &wrap
noremap <script> ? H0:call <SID>Backward()<CR>?
else
noremap <script> ? Hg0:call <SID>Backward()<CR>?
endif

fun! s:Forward()
" Searching forward
noremap <script> n H$nzt<SID>L
if &wrap
noremap <script> N H0Nzt<SID>L
else
noremap <script> N Hg0Nzt<SID>L
endif
cnoremap <silent> <script> <CR> <CR>:cunmap <lt>CR><CR>zt<SID>L
endfun

fun! s:Backward()
" Searching backward
if &wrap
noremap <script> n H0nzt<SID>L
else
noremap <script> n Hg0nzt<SID>L
endif
noremap <script> N H$Nzt<SID>L
cnoremap <silent> <script> <CR> <CR>:cunmap <lt>CR><CR>zt<SID>L
endfun

call s:Forward()

" Quitting
noremap q :q<CR>

" Switch to editing (switch off less mode)
map v :silent call <SID>End()<CR>
fun! s:End()
set ma
if exists('s:lz')
let &lz = s:lz
endif
unmap h
unmap H
unmap <Space>
unmap <C-V>
unmap f
unmap <C-F>
unmap z
unmap <Esc><Space>
unmap F
unmap d
unmap <C-D>
unmap <CR>
unmap <C-N>
unmap e
unmap <C-E>
unmap j
unmap <C-J>
unmap b
unmap <C-B>
unmap w
unmap <Esc>v
unmap u
unmap <C-U>
unmap k
unmap y
unmap <C-Y>
unmap <C-P>
unmap <C-K>
unmap r
unmap <C-R>
unmap R
unmap g
unmap <
unmap <Esc><
unmap G
unmap >
unmap <Esc>>
unmap %
unmap p
unmap n
unmap N
unmap q
unmap v
unmap /
unmap ?
endfun

" vim: sw=2