Generic :python command in vim?

Question

Within a vim script it is possible to embed some python code, as long as vim is built with the +python feature.

function! IcecreamInitialize()
python << EOF
class StrawberryIcecream:
    def __call__(self):
        print('EAT ME')
EOF
endfunction

However, some people have vim built with +python3 instead. This brings up some compatibility issues for vim plugins. Is there a generic command which calls whichever python version is installed on the computer?

The short answer is no. Thne longer answer is you can abstract some of it out, by testing which version of Python is available, setting a variable say `py` to either `python` or `python3`, and then calling that with `exec py . ' print("EAT ME")'`. Yeah, I never said it was nice. — lcd047, Jun 19 '15 at 18:13

Lerner Zhang · Answer 1 · 2015-07-25T12:53:11.510

This snippet could determine which Python version we're using and switch to it(Python stands for that version installed).

if has('python')
    command! -nargs=1 Python python <args>
elseif has('python3')
    command! -nargs=1 Python python3 <args>
else
    echo "Error: Requires Vim compiled with +python or +python3"
    finish
endif

To load the python code, we first figure out its location(here under the same directory as the Vim Script):

execute "Python import sys"
execute "Python sys.path.append(r'" . expand("<sfile>:p:h") . "')"

Then check if the python module is available. If not, reload it:

Python << EOF
if 'yourModuleName' not in sys.modules:
    import yourModuleName
else:
    import imp
    # Reload python module to avoid errors when updating plugin
    yourModuleName = imp.reload(yourModuleName)
EOF

Two ways to call it:
1.

" call the whole module
execute "Python yourModuleName"

" call a function from that module
execute "Python yourModuleName.aMethod()"

2.

" Call a method using map 
vnoremap <leader> c :Python yourModuleName.aMethod()<cr> 

" Call a module or method using Vim function
vnoremap <leader> c :<c-u> <SID>yourFunctionName(visualmode())<cr>
function! s:YourFunctionName(someName)
    Python YourFunctionName.aMethod(a:someName)
    Python YourFunctionName
endfunction

Martin Tournoij · Answer 2 · 2015-07-01T22:20:13.107

The "heredoc" (<< EOF) syntax is limited only to the script :py, :perl, etc.) commands; you can't use them with normal strings. And using line-continuation in Vim is a bit of a pain.

For this reason, I would put the Python code in a separate file, and pass this to the :py or :py3 commands.

let mycode = join(readfile(expand('~/mycode.py')), "\n")

if has('python')
    execute 'py ' . mycode
elseif has('python3')
    execute 'py3 ' . mycode
else
    echoe 'Your mother was a hamster'
endif

And the mycode.py script:

import sys
import vim
print('This is mycode', sys.version)

vim.command(':echo "Hello"')
print(vim.eval('42'))

From Python 2:

('This is mycode', '2.7.10 (default, May 26 2015, 04:16:29) \n[GCC 5.1.0]')
Hello
42

And from Python 3:

This is mycode 3.4.3 (default, Mar 25 2015, 17:13:50)
[GCC 4.9.2 20150304 (prerelease)]
Hello
42

Generic :python command in vim?

2 Answers2