Vim script: Buffer/CheatSheet Toggle - vim

Question

I want to make a vim cheat sheet plugin. It's real simple:
I want to toggle my cheatsheets. A vertsplit toggle, like Taglist or NERDTree.
I want the cheatsheet to be filetype specific. So I toggle my c++ cheatsheet when I have opened a .cpp file.
I want the cheatsheet to be horizontally split. So it shows two files, my syntax cheat sheet and my snippet trigger cheat sheet.
I already have a collection of these cheatsheets, in vimhelp format, but now I have to manually open them.
I haven't really done any vim scripting, but I imagine this would be really simple to put together. I'm sorta sick of googling unrelated codesnippets, so what I'm asking here is:
Could anyone give me a short sum-up of what I need to learn in regards to vim scripting to piece this together. What I have a hard time finding is how to toggle the buffer window.
If you know any intro tutorials that covers the material I need to get this up and running, please provide a link.
tx,
aktivb

Answer 1

The function below may not do exactly what you want, and I haven't tested it, but it should give you some ideas.
The main idea is that the function reads the filetype of the current buffer (you can test this by typing :echo &ft) and then sets the path of the appropriate cheat sheat. If it exists, this path is then opened (read-only and non-modifiable) in a split window. You can then call this function any way you wish, for example by mapping it to the {F5} key as shown.
I'm not sure about the toggling possibilities (is this really easier than just closing the split window?) but you could look at the bufloaded() function, which returns whether or not a given file is currently being accessed.
function! Load_Cheat_Sheet()
let l:ft = &ft
if l:ft == 'html'
let l:path = 'path/to/html/cheat/sheet'
elseif l:ft == 'c'
let l:path = 'path/to/c/cheat/sheet'
elseif l:ft == 'tex'
let l:path = 'path/to/tex/cheat/sheet'
endif
if l:path != '' && filereadable(l:path)
execute ':split +setlocal\ noma\ ro ' l:path
endif
endfunction
map <F5> :call Load_Cheat_Sheet()<CR>
Hope this helps. Just shout if anything is unclear, or you want to know more.

Answer 2

I had forgotten about this until I got a notice about Eduan's answer. Since I posted this question I've done quite a bit of vim scripting, including getting this to work:
let g:cheatsheet_dir = "~/.vim/bundle/cheatsheet/doc/"
let g:cheatsheet_ext = ".cs.txt"
command! -nargs=? -complete=customlist,CheatSheetComplete CS call ToggleCheatSheet(<f-args>)
nmap <F5> :CS<CR>
" strip extension from complete list
function! CheatSheetComplete(A,L,P)
return map(split(globpath(g:cheatsheet_dir, a:A.'*'.g:cheatsheet_ext)),
\ "v:val[".strlen(expand(g:cheatsheet_dir)).
\ ":-".(strlen(g:cheatsheet_ext) + 1)."]")
endfun
" specify cheatsheet or use filetype of open buffer as default
" instead of saving window status in a boolean variable,
" test if the file is open (by name). If a boolean is used,
" you'll run into trouble if you close the window manually with :wq etc
function! ToggleCheatSheet(...)
if a:0
let s:file = g:cheatsheet_dir.a:1.g:cheatsheet_ext
else
if !exists("s:file") || bufwinnr(s:file) == -1
let s:file = g:cheatsheet_dir.&ft.g:cheatsheet_ext
endif
endif
if bufwinnr(s:file) != -1
call ToggleWindowClose(s:file)
else
call ToggleWindowOpen(s:file)
endif
endfun
" stateless open and close so it can be used with other plugins
function! ToggleWindowOpen(file)
let splitr = &splitright
set splitright
exe ":vsp ".a:file
exe ":vertical resize 84"
if !splitr
set splitright
endif
endfun
function! ToggleWindowClose(file)
let w_orig = bufwinnr('%')
let w = bufwinnr(a:file)
exe w.'wincmd w'
exe ':silent wq!'
if w != w_orig
exe w_orig.'wincmd w'
endif
endfun

Answer 3

Thought I would add to Goulash's answer.
I think in order to implement the toggle you would simply use some if statements and a global variable.
let g:cheatsheet_toggle_on=0
if (g:cheatsheet_toggle_on == 0)
" Turn the cheatsheet on
" Also make sure to know that the toggle is on:
let g:cheatsheet_toggle_on=1
elseif (g:cheatsheet_toggle_on=1
" Do whatever you need to turn it off, here
endif
Hope this figures out that logic. :)