Integrate Pylint and Pychecker support

Previous Tip • Next Tip

Tip: #949 - Integrate Pylint and Pychecker support

Created: June 9, 2005 18:41 Complexity: intermediate Author: Dave Vehrs Version: 6.0 Karma: 11/5 Imported from: Tip#949

Simple function to add pylint and pychecker support to Vim.

function <SID>PythonGrep(tool) 
  set lazyredraw 
  " Close any existing cwindows. 
  cclose 
  let l:grepformat_save = &grepformat 
  let l:grepprogram_save = &grepprg 
  set grepformat&vim 
  set grepformat&vim 
  let &grepformat = '%f:%l:%m' 
  if a:tool == "pylint" 
    let &grepprg = 'pylint --parseable=y --reports=n' 
  elseif a:tool == "pychecker" 
    let &grepprg = 'pychecker --quiet -q' 
  else 
    echohl WarningMsg 
    echo "PythonGrep Error: Unknown Tool" 
    echohl none 
  endif 
  if &readonly == 0 | update | endif 
  silent! grep! % 
  let &grepformat = l:grepformat_save 
  let &grepprg = l:grepprogram_save 
  let l:mod_total = 0 
  let l:win_count = 1 
  " Determine correct window height 
  windo let l:win_count = l:win_count + 1 
  if l:win_count <= 2 | let l:win_count = 4 | endif 
  windo let l:mod_total = l:mod_total + winheight(0)/l:win_count | 
   \ execute 'resize +'.l:mod_total 
  " Open cwindow 
  execute 'belowright copen '.l:mod_total 
  nnoremap <buffer> <silent> c :cclose<CR> 
  set nolazyredraw 
  redraw! 
endfunction 

if ( !hasmapto('<SID>PythonGrep(pylint)') && (maparg('<F3>') == ) ) 
  map <F3> :call <SID>PythonGrep('pylint')<CR> 
  map! <F3> :call <SID>PythonGrep('pylint')<CR> 
else 
  if ( !has("gui_running") || has("win32") ) 
    echo "Python Pylint Error: No Key mapped.\n". 
     \ "<F3> is taken and a replacement was not assigned." 
  endif 
endif 

if ( !hasmapto('<SID>PythonGrep(pychecker)') && (maparg('<F4>') == ) ) 
  map <F4> :call <SID>PythonGrep('pychecker')<CR> 
  map! <F4> :call <SID>PythonGrep('pychecker')<CR> 
else 
  if ( !has("gui_running") || has("win32") ) 
    echo "Python Pychecker Error: No Key mapped.\n". 
     \ "<F8> is taken and a replacement was not assigned." 
  endif 
endif

Comments

Good tip! A suggestion is to use the compiler functionality in Vim (see :help :compiler). To create a compiler file for pychecker, create the following in 'pychecker.vim' (and place it in e.g. "~/.vim/compiler/" on a unix-style system)::

" Vim compiler file 
" Compiler: Pychecker for Python 
if exists("current_compiler") 
  finish 
 endif 
let current_compiler = "pychecker" 

if exists(":CompilerSet") != 2 " older Vim always used :setlocal 
  command -nargs=* CompilerSet setlocal <args> 
endif 

CompilerSet makeprg=pychecker\ % 
CompilerSet efm=%f:%l:%m 

niklasl , June 14, 2005 15:30

---

One flaw with the compiler way is that it searches all modules recursively for errors by default. It then opens the current window to the first error it finds, commonly in a module. While this is good if you wrote and are testing the modules, its not so good when you did not and would rather focus on your own project.

I tried to fix this by editting the makeprg line to match that used above. However, the compiler method tends to break on simple errors. For example:

I changed:

CompilerSet makeprg=pychecker\ % 

to:

CompilerSet makeprg=pychecker\ --quiet\ -q\ % 

or:

CompilerSet makeprg=pychecker\ --quiet\ % 

or:

CompilerSet makeprg=pychecker\ -q\ % 

Then i made one small change to a file that previously tested errorfree. I changed a "not" to a "!" in an if statement (common mistake for me).

I then entered the :make command and vim responded with:

"pydsh" [New File] 
(4 of 4): NOT PROCESSED UNABLE TO IMPORT 
Hit ENTER or type command to continue 

and opened a new empty buffer (:bd to close).

On the other hand, I pressed F3 or F4 for my function and was presented with a open cwindow below my window with one line in it: "pydsh.py|860| [E] invalid syntax" which when selected took me to the line with the problem.

Which would you rather use?

Dave Vehrs , June 14, 2005 20:28

---

Wait my mistake.

Pylint (F3 for me) responds with the above.

Pychecker (F4) responds by openning a cwindow with:

|| SyntaxError: invalid syntax (pydsh.py, line 860) 
|| if ( ! options.scp_proto.lower() == "scp" 
|| ^ 
pydsh|1| NOT PROCESSED UNABLE TO IMPORT 

Which does not take me automatically to the line in question but it is slightly better than the compiler method in that it shows me a line number and error.

Dave Vehrs , June 14, 2005 20:34

---