PythonのデコレータでVim ScriptからでもPythonからでも呼べる関数を定義する

define_function_in_python.vim

python <<EOM
# coding=utf-8
import vim

vim.command("""
function! Hoge(str)
    return a:str . a:str
endfunction
""")

_functions_for_vim = {}
def vimfunc(name):
    def _(func):
        _functions_for_vim[name] = func

        vim.command("""
            function! {0}(...)
                python vim.command('return "' +  _functions_for_vim['{0}'](vim.eval('a:000')) + '"')
            endfunction
        """.format(name))

        def __(*args, **keywords):
            return func(args)
        return __
    return _

@vimfunc('s:fuga')
def fuga(args):
    return args[0] * int(args[1])

@vimfunc('Piyo')
def piyo(args):
    return ','.join(args)

EOM

echo Hoge('ほげ')
" => ほげほげ

echo s:fuga('ふが', 5)
" => ふがふがふがふがふが

python print fuga('ふが', 5)
" => ふがふがふがふがふが

echo Piyo(3, 4, 5)

python print piyo('3', '4', '5')