Avoid str.format() if possible

The server should be started with `nvim --listen /tmp/nvimsocket` or just `nvr`.

When used as client, nvr still supports $NVIM_LISTEN_ADDRESS for backward
compatibility.

README.md

@@ -31,12 +31,12 @@ If you encounter any issues, e.g. permission denied errors or you can't find the
 
 ## Theory
 
-Nvim always starts a server. Get its address via `:echo $NVIM_LISTEN_ADDRESS` or
-`:echo v:servername`. Or specify an address at startup:
-`NVIM_LISTEN_ADDRESS=/tmp/nvimsocket nvim`.
+**Nvim** always starts a server. Get its address with `:echo v:servername`. Or
+specify an address at startup: `nvim --listen /tmp/nvimsocket`.
 
-**nvr** will use `$NVIM_LISTEN_ADDRESS` or any address given to it via
-`--servername`.
+**nvr** (the client) will use any address given to it via `--servername`,
+`$NVIM_LISTEN_ADDRESS` (obsolete in nvim but still supported in nvr), or
+defaults to `/tmp/nvimsocket`.
 
 If the targeted address does not exist, **nvr** starts a new process by running
 "nvim". You can change the command by setting `$NVR_CMD`. _(This requires
@@ -46,7 +46,7 @@ forking, so it won't work on Windows.)_
 
 Start a nvim process (which acts as a server) in one shell:
 
-    NVIM_LISTEN_ADDRESS=/tmp/nvimsocket nvim
+    nvim --listen /tmp/nvimsocket
 
 And do this in another shell:
 
@@ -155,18 +155,19 @@ Happy hacking!
 
     Easy-peasy! Just `nvr file`.
 
-    This works without any prior setup, because `$NVIM_LISTEN_ADDRESS` is always
-    set within Nvim. And `nvr` will default to that address.
+    This works without any prior setup, because `$NVIM` is always set for all
+    children of the nvim process, including `:terminal`, and `nvr` will default
+    to that address.
 
     I often work with two windows next to each other. If one contains the
     terminal, I can use `nvr -l foo` to open the file in the other window.
 
 - **Open files always in the same nvim process no matter which terminal you're in.**
 
-    If you just run `nvr -s`, a new nvim process will start and set its address
-    to `/tmp/nvimsocket` automatically.
+    Just `nvr -s` starts a new nvim process with the server address set to
+    `/tmp/nvimsocket`.
 
-    Now, no matter in which terminal you are, `nvr file` will always work on
+    Now, no matter which terminal you are in, `nvr file` will always work on
     that nvim process. That is akin to `emacsclient` from Emacs.
 
 - **Use nvr in plugins.**

nvr/nvr.py

@@ -62,8 +62,7 @@ class Nvr():
                     self.started_new_process = True
                     return main2(nvr, options, arguments)
                 time.sleep(0.2)
-            print('[!] Unable to attach to the new nvim process. Is `{}` working?'
-                    .format(" ".join(args)))
+            print(f'[!] Unable to attach to the new nvim process. Is `{" ".join(args)}` working?')
             sys.exit(1)
 
     def execute_new_nvim_process(self, silent, nvr, options, arguments):
@@ -83,7 +82,7 @@ class Nvr():
         try:
             os.execvpe(args[0], args, os.environ)
         except FileNotFoundError:
-            print("[!] Can't start new nvim process: '{}' is not in $PATH.".format(args[0]))
+            print(f'[!] Can\'t start new nvim process: `{args[0]}` is not in $PATH.')
             sys.exit(1)
 
     def read_stdin_into_buffer(self, cmd):
@@ -98,7 +97,7 @@ class Nvr():
         path = self.server.funcs.fnameescape(path)
         shortmess = self.server.options['shortmess']
         self.server.options['shortmess'] = shortmess.replace('F', '')
-        self.server.command('{} {}'.format(cmd, path))
+        self.server.command(f'{cmd} {path}')
         self.server.options['shortmess'] = shortmess
 
     def diffthis(self):
@@ -112,8 +111,8 @@ class Nvr():
         chanid = self.server.channel_id
 
         self.server.command('augroup nvr')
-        self.server.command('autocmd BufDelete <buffer> silent! call rpcnotify({}, "BufDelete")'.format(chanid))
-        self.server.command('autocmd VimLeave * if exists("v:exiting") && v:exiting > 0 | silent! call rpcnotify({}, "Exit", v:exiting) | endif'.format(chanid))
+        self.server.command(f'autocmd BufDelete <buffer> silent! call rpcnotify({chanid}, "BufDelete")')
+        self.server.command(f'autocmd VimLeave * if exists("v:exiting") && v:exiting > 0 | silent! call rpcnotify({chanid}, "Exit", v:exiting) | endif')
         self.server.command('augroup END')
 
         if 'nvr' in bvars:
@@ -178,7 +177,7 @@ def is_netrw_protocol(path):
 
 def parse_args(argv):
     form_class = argparse.RawDescriptionHelpFormatter
-    usage      = '{} [arguments]'.format(argv[0])
+    usage      = argv[0] + ' [arguments]'
     epilog     = 'Development: https://github.com/mhinz/neovim-remote\n\nHappy hacking!'
     desc       = textwrap.dedent("""
         Remote control Neovim processes.
@@ -309,36 +308,40 @@ def parse_args(argv):
 
 
 def show_message(address):
-    print(textwrap.dedent('''
-        [!] Can't connect to: {}
+    print(textwrap.dedent(f'''
+        [!] Can't connect to: {address}
 
             The server (nvim) and client (nvr) have to use the same address.
 
             Server:
 
-                Expose $NVIM_LISTEN_ADDRESS to the environment before
-                starting nvim:
+                Specify the server address when starting nvim:
 
-                $ NVIM_LISTEN_ADDRESS={} nvim
+                $ nvim --listen {address}
 
                 Use `:echo v:servername` to verify the address.
 
-                Security: When using Unix domain sockets on a multi-user system,
-                the socket should have proper permissions so that it is only
-                accessible by your user.
+                Alternatively, run nvr without arguments. It defaults to
+                starting a new nvim process with the server name set to
+                "/tmp/nvimsocket".
+
+                Security: When using an Unix domain socket, that socket should
+                have proper permissions so that it is only accessible by your
+                user.
 
             Client:
 
-                Expose $NVIM_LISTEN_ADDRESS to the environment before
-                using nvr or use its --servername option. If neither
-                is given, nvr assumes \"/tmp/nvimsocket\".
+                Expose $NVIM_LISTEN_ADDRESS (obsolete in nvim but still
+                supported by nvr) to the environment before using nvr or use
+                its --servername option. If neither is given, nvr assumes
+                \"/tmp/nvimsocket\".
 
-                $ NVIM_LISTEN_ADDRESS={} nvr file1 file2
-                $ nvr --servername {} file1 file2
+                $ NVIM_LISTEN_ADDRESS={address} nvr file1 file2
+                $ nvr --servername {address} file1 file2
                 $ nvr --servername 127.0.0.1:6789 file1 file2
 
             Use -s to suppress this message.
-        '''.format(address, address, address, address)))
+        '''))
 
 
 def split_cmds_from_files(args):
@@ -358,10 +361,10 @@ def split_cmds_from_files(args):
 
 def print_versions():
     import pkg_resources
-    print('nvr {}'.format(pkg_resources.require('neovim-remote')[0].version))
-    print('pynvim {}'.format(pkg_resources.require('pynvim')[0].version))
-    print('psutil {}'.format(pkg_resources.require('psutil')[0].version))
-    print('Python {}'.format(sys.version.split('\n')[0]))
+    print('nvr ' + pkg_resources.require("neovim-remote")[0].version)
+    print('pynvim ' + pkg_resources.require('pynvim')[0].version)
+    print('psutil ' + pkg_resources.require('psutil')[0].version)
+    print('Python ' + sys.version.split('\n')[0])
 
 
 def print_addresses():
@@ -379,7 +382,7 @@ def print_addresses():
                     if conn.laddr:
                         addresses.insert(0, conn.laddr)
             except psutil.AccessDenied:
-                errors.insert(0, 'Access denied for nvim ({})'.format(proc.pid))
+                errors.insert(0, f'Access denied for nvim ({proc.pid})')
 
     for addr in sorted(addresses):
         print(addr)
@@ -408,7 +411,7 @@ def main(argv=sys.argv, env=os.environ):
         print_addresses()
         return
 
-    address = options.servername or env.get('NVIM_LISTEN_ADDRESS') or '/tmp/nvimsocket'
+    address = options.servername or env.get('NVIM') or env.get('NVIM_LISTEN_ADDRESS') or '/tmp/nvimsocket'
 
     nvr = Nvr(address, options.s)
     nvr.attach()
@@ -468,11 +471,11 @@ def main2(nvr, options, arguments):
         try:
             result = nvr.server.eval(options.remote_expr)
         except:
-            print(textwrap.dedent("""
-                No valid expression: {}
+            print(textwrap.dedent(f"""
+                No valid expression: {options.remote_expr}
                 Test it in Neovim: :echo eval('...')
                 If you want to execute a command, use -c or -cc instead.
-            """).format(options.remote_expr))
+            """))
         if type(result) is bytes:
             print(result.decode())
         elif type(result) is list:
@@ -509,14 +512,14 @@ def main2(nvr, options, arguments):
 
     if options.t:
         try:
-            nvr.server.command("tag {}".format(options.t))
+            nvr.server.command('tag ' + options.t)
         except nvr.server.error as e:
             print(e)
             sys.exit(1)
 
     if options.q:
         path = nvr.server.funcs.fnameescape(os.environ['PWD'])
-        nvr.server.command('lcd {}'.format(path))
+        nvr.server.command('lcd ' + path)
         nvr.server.funcs.setqflist([])
         if options.q == '-':
             for line in sys.stdin:

setup.py

@@ -14,13 +14,13 @@ setup(
     description      = 'Control nvim processes using "nvr" commandline tool',
     long_description = long_description,
     long_description_content_type = 'text/markdown',
-    python_requires  = '>=3.5',
+    python_requires  = '>=3.7',
     install_requires = ['pynvim', 'psutil', 'setuptools'],
     entry_points     = {
         'console_scripts': ['nvr = nvr.nvr:main']
     },
     packages         = ['nvr'],
-    version          = '2.4.0',
+    version          = '2.4.2',
     license          = 'MIT',
     keywords         = 'neovim nvim nvr remote helper',
     classifiers      = [
@@ -30,10 +30,6 @@ setup(
         'Intended Audience :: End Users/Desktop',
         'Intended Audience :: Developers',
         'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.5',
-        'Programming Language :: Python :: 3.6',
-        'Programming Language :: Python :: 3.7',
-        'Programming Language :: Python :: 3.8',
     ],
 )