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135 lines
6.0 KiB
Plaintext
135 lines
6.0 KiB
Plaintext
*remote_plugin.txt* For Nvim. {Nvim}
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NVIM REFERENCE MANUAL by Thiago de Arruda
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Nvim support for remote plugins *remote-plugin*
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1. Introduction |remote-plugin-intro|
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2. Plugin hosts |remote-plugin-hosts|
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3. Example |remote-plugin-example|
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4. Plugin manifest |remote-plugin-manifest|
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==============================================================================
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1. Introduction *remote-plugin-intro*
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Extensibility is a primary goal of Nvim. Any programming language may be used
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to extend Nvim without changes to Nvim itself. This is achieved with remote
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plugins, coprocesses that have a direct communication channel (via |RPC|) with
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the Nvim process.
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Even though these plugins run in separate processes they can call, be called,
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and receive events just as if the plugin's code were executed in the main
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process.
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==============================================================================
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2. Plugin hosts *remote-plugin-hosts*
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While plugins can be implemented as arbitrary programs that communicate
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directly with the high-level Nvim API and are called via |rpcrequest()| and
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|rpcnotify()|, that is not the best approach. Instead, developers should first
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check whether a plugin host is available for their chosen programming language.
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Plugin hosts are programs that provide a high-level environment for plugins,
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taking care of most boilerplate involved in defining commands, autocmds, and
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functions that are implemented over |RPC| connections. Hosts are loaded only
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when one of their registered plugins require it, keeping Nvim's startup as
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fast as possible, even if many plugins/hosts are installed.
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==============================================================================
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3. Example *remote-plugin-example*
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The best way to learn about remote plugins is with an example, so let's see
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what a Python plugin looks like. This plugin exports a command, a function, and
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an autocmd. The plugin is called 'Limit', and all it does is limit the number
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of requests made to it. Here's the plugin source code:
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>
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import neovim
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@neovim.plugin
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class Limit(object):
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def __init__(self, vim):
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self.vim = vim
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self.calls = 0
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@neovim.command('Cmd', range='', nargs='*', sync=True)
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def command_handler(self, args, range):
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self._increment_calls()
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self.vim.current.line = (
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'Command: Called %d times, args: %s, range: %s' % (self.calls,
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args,
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range))
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@neovim.autocmd('BufEnter', pattern='*.py', eval='expand("<afile>")',
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sync=True)
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def autocmd_handler(self, filename):
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self._increment_calls()
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self.vim.current.line = (
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'Autocmd: Called %s times, file: %s' % (self.calls, filename))
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@neovim.function('Func')
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def function_handler(self, args):
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self._increment_calls()
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self.vim.current.line = (
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'Function: Called %d times, args: %s' % (self.calls, args))
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def _increment_calls(self):
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if self.calls == 5:
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raise Exception('Too many calls!')
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self.calls += 1
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<
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As can be seen, the plugin is implemented using idiomatic Python (classes,
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methods, and decorators). The translation between these language-specific
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idioms to Vimscript occurs while the plugin manifest is being generated (see
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the next section).
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Notice that the exported command and autocmd are defined with the "sync" flag,
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which affects how Nvim calls the plugin: with "sync" the |rpcrequest()|
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function is used, which will block Nvim until the handler function returns a
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value. Without the "sync" flag, the call is made using a fire and forget
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approach with |rpcnotify()|, meaning return values or exceptions raised in the
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handler function are ignored.
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To test the above plugin, it must be saved in "rplugin/python" in a
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'runtimepath' directory (~/.config/nvim/rplugin/python/limit.py for example).
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Then, the remote plugin manifest must be generated with
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`:UpdateRemotePlugins`.
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==============================================================================
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4. Remote plugin manifest *remote-plugin-manifest*
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Just installing remote plugins to "rplugin/{host}" isn't enough for them to be
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automatically loaded when required. You must execute `:UpdateRemotePlugins`
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every time a remote plugin is installed, updated, or deleted.
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`:UpdateRemotePlugins` generates the remote plugin manifest, a special
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Vimscript file containing declarations for all Vimscript entities
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(commands/autocommands/functions) defined by all remote plugins, with each
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entity associated with the host and plugin path. The manifest is a generated
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extension to the user's vimrc (it even has the vimrc filename prepended).
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Manifest declarations are just calls to the `remote#host#RegisterPlugin`
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function, which takes care of bootstrapping the host as soon as the declared
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command, autocommand, or function is used for the first time.
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The manifest generation step is necessary to keep Nvim's startup fast in
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situations where a user has remote plugins with different hosts. For example,
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say a user has three plugins, for Python, Java and .NET hosts respectively. If
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we were to load all three plugins at startup, then three language runtimes
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would also be spawned, which could take seconds!
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With the manifest, each host will only be loaded when required. Continuing with
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the example, say the Java plugin is a semantic completion engine for Java code.
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If it defines the autocommand "BufEnter *.java", then the Java host is spawned
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only when Nvim loads a buffer matching "*.java".
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If the explicit call to `:UpdateRemotePlugins` seems incovenient, try to see it
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like this: It's a way to provide IDE capabilities in Nvim while still keeping
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it fast and lightweight for general use. It's also analogous to the |:helptags|
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command.
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==============================================================================
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vim:tw=78:ts=8:noet:ft=help:norl:
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