fix(Save-/LoadMarks): add opt to keep original file-ext

[juanMarinero]

• Previous let l:path = substitute(l:path, expand("%:e"), "json", "") did replace first extension match. E.g. filepy.py would be filejson.py
• If I have multiple files with same filename (without extension), like main.js and main.html, then now with let g:codepainter_file_keep_original_extension = 1 I can have 2 different codepainter JSONs (main.js.json and main.html.json). Or if set to 0 just main.json as previous to this PR
• Previous potential overwrite if script with marks is also a JSON. Now codepainter#SaveMarks() echoes a warning, thus silent removed from PainterSaveMarks declaration to see those error-msgs

Next is an example of what now can be achieved. TLDR: create JSON files for auto-save/load codepainter-marks with a regex that matches .gitignore. Example of how to use:

1. vim filepy.py
2. [Create a codepainter mark]
3. :call SaveCodePaintersToJSON() creates filepy.py__noGit_vim-codePainters.json. Which is awesome since py of filepyis not renamed by let l:path = substitute(l:path, expand("%:e"), "json", "") and adds _noGit_ for the .gitignore
4. Exit vim
5. vim filepy.py
6. :call SourceCodePaintersFromJSON() loads filepy.py__noGit_vim-codePainters.json

" Source marks from JSON
nmap <leader>mmso :call SourceCodePaintersFromJSON()<CR>

" Save marks to JSON
nmap <leader>mmsa :call SaveCodePaintersToJSON()<CR>

function! SetCodePaintersFile()
  " Check if g:codepaints_file_default_suffix is defined, and set a default if not
  if !exists('g:codepaints_file_default_suffix')
    let g:codepaints_file_default_suffix = '__noGit_vim-codePainters.json'
  endif

  " Full path
  " Keep file extension, to prevent overwriting codePainters-associated files with the same name. E.g. of main.js and main.html
  " Not valid cause 'PainterSaveMarks' rewrites the first ext to 'json' 
  " even if e.g. ext is in part of the file name
  " e.g. file_py.py is renamed to file_json.py
  " See codepainter#LoadMarks(...) and codepainter#SaveMarks(...) in
  " autoload/codepainter.vim
  " Yes valid since current PR !!!!!!!!!!!!
  let l:current_file = expand('%:p')

  " Add suffix
  let l:codepaints_file = l:current_file . g:codepaints_file_default_suffix

  " Return the code_painter file path
  return l:codepaints_file
endfunction

function! SaveCodePaintersToJSON()
  " Call SetCodePaintersFile to set up the bookmark file path
  let l:codepaints_file = SetCodePaintersFile()

  " Check if file already exists
  if filereadable(l:codepaints_file)
    let l:choice = input('Overwrite ' . l:codepaints_file . '? (y/n): ')
    if l:choice !~? '^y'
      echo 'CodePaints save cancelled'
      return
    endif
  endif

  execute 'PainterSaveMarks ' . l:codepaints_file
  echo 'Code paints saved to ' . l:codepaints_file
endfunction

function! SourceCodePaintersFromJSON()
  " Call SetCodePaintersFile to set up the bookmark file path
  let l:codepaints_file = SetCodePaintersFile()

  if !filereadable(l:codepaints_file)
    echo 'Code paints file not found: ' . l:codepaints_file
    return
  endif

  execute 'PainterLoadMarks ' . l:codepaints_file
  echo 'Code paints sourced from ' . l:codepaints_file
endfunction

[juanMarinero]

Amend. I said

create JSON files for auto-save/load codepainter-marks

Though to be auto it would need alike:

au BufReadPost * if empty(&buftype) | call SourceCodePaintersFromJSON() | endif
au BufUnload * if empty(&buftype) | call SaveCodePaintersToJSON() | endif

• BufReadPost seems ok. It is convenient: it loads the associated codepainter JSON (if already exists) on file open. I think it runs on regular scripts only (for example to not be triggered when git-status, :Git, of vim-fugitive loads).
• BufUnload is NOT ok. It also only runs on regular scripts. To be triggered on respective-buffer-unload I edited:

au BufUnload * if empty(&buftype) | call SaveCodePaintersToJSON(expand('<afile>:p')) | endif

function! SetCodePaintersFile(...)
  [...] 
  
  " replaced next: let l:current_file = expand('%:p')
  let l:current_file = a:0 > 0 ? a:1 : expand('%:p')
  
  [...]
endfunction

function! SaveCodePaintersToJSON(...)
  [...]
  
  " replaced next: let l:codepaints_file = SetCodePaintersFile()
  let l:codepaints_file = a:0 == 0 ? SetCodePaintersFile() : SetCodePaintersFile(a:1)  
  
  [...]
endfunction

But BufUnload is not working as desired. I think that codepainter#SaveMarks is saving marks from all buffers into each file, rather than just saving the marks specific to each buffer.
Example

1. vim file1.py which has its respective codepainter-marks JSON created
2. :echo g:marks shows e.g. {'1': [[[0, 1, 1, 0], [0, 1, 5, 0], 0, 'paint0']]}
3. :q
4. vim -p file1.py A.json filepy.py where all they already had their respective codepainter-marks JSON created
5. :echo g:marks shows e.g. {'1': [[[0, 1, 1, 0], [0, 1, 5, 0], 0, 'paint0'], [[0, 1, 1, 0], [0, 1, 2, 0], 1, 'paint0']], '2': [[[0, 2, 3, 0], [0, 2, 7, 0], 2, 'paint0']], '3': [[[0, 3, 13, 0], [0, 3, 20, 0], 3, 'paint0' ], [[0, 3, 1, 0], [0, 3, 3, 0], 4, 'paint0']], '5': [[[0, 5, 1, 0], [0, 5, 6, 0], 5, 'paint3']]} instead of just marks of first buffer file1.py.

Alike happens with the BufUnload command which calls SaveCodePaintersToJSON and this calls codepainter#SaveMarks.
Example

1. vim -p file1.py A.json filepy.py. Where all they already had their respective codepainter-marks JSON created.
2. If I :q file1.py and filepy.py nothing happens. Then when I quit A.json I am asked:

    Overwrite ~/Downloads/deleteme/file1.py__noGit_vim-codePainters.json? (y/n): y
    Overwrite ~/Downloads/deleteme/A.json__noGit_vim-codePainters.json? (y/n): n
    Overwrite ~/Downloads/deleteme/filepy.py__noGit_vim-codePainters.json? (y/n): n

7. I answered y save just file1.py__noGit_vim-codePainters.json
8. But in that file I get the mix of all the 3 JSONs (file1.py__noGit_vim-codePainters.json, A.json__noGit_vim-codePainters.json and filepy.py__noGit_vim-codePainters.json) as vim file1.py can show.

Please help. To fix codepainter#SaveMarks saving marks from all buffers rather than just saving the marks specific to each buffer.

Maybe vim-bookmarks approach can be replicated here (way beyond my vimscript skills though). This plugin offers different strategies to save bookmarks:

• Global (in ~/.vim-bookmarks by default)
• Per working directory
• Per buffer
• Or none of the above, like manual. It's called Silent saving and loading

Maybe all this auto-stuff goes beyond this PR and if this PR is accepted then I should create an issue (feature request).