languageserver: An implementation of the Language Server Protocol for R

languageserver is an implementation of the Microsoft's Language Server Protocol for the language of R.

• Installation
• Language Clients
• Services Implemented
• Settings
• FAQ
  • Linters
  • Customizing server capabilities
  • Customizing formatting style

Installation

A few dependencies are required beforehand:

# On Debian, Ubuntu, etc.
apt install --assume-yes --no-install-recommends build-essential libcurl4-openssl-dev libssl-dev libxml2-dev r-base

# On Fedora, Centos, etc.
dnf install --assumeyes --setopt=install_weak_deps=False @development-tools libcurl-devel libxml2-devel openssl-devel R

# On Alpine
apk add --no-cache curl-dev g++ gcc libxml2-dev linux-headers make R R-dev

languageserver is released on CRAN and can be easily installed by

install.packages("languageserver")

To try the latest features, install the daily development build from our r-universe repository:

install.packages("languageserver", repos = c(
    reditorsupport = "https://reditorsupport.r-universe.dev",
    getOption("repos")
))

Or install the latest development version from our GitHub repository:

# install.packages("remotes")
remotes::install_github("REditorSupport/languageserver")

Language Clients

The following editors are supported by installing the corresponding extensions:

• VS Code: vscode-R

• Atom: atom-ide-r

• Sublime Text: R-IDE

• Vim/NeoVim: LanguageClient-neovim with settings

  let g:LanguageClient_serverCommands = {
      \ 'r': ['R', '--slave', '-e', 'languageserver::run()'],
      \ }

  or, if you use coc.nvim, you can do one of two things:

  • Install coc-r-lsp with:

    :CocInstall coc-r-lsp

  • or install the languageserver package in R

    install.packages("languageserver")
    # or install the developement version
    # remotes::install_github("REditorSupport/languageserver")

    Then add the following to your Coc config:

    "languageserver": {
        "R": {
            "command": "/usr/bin/R",
            "args" : [ "--slave", "-e", "languageserver::run()"],
            "filetypes" : ["r"]
        }
    }

• Emacs: lsp-mode

• JupyterLab: jupyterlab-lsp

• BBEdit: preconfigured in version 14.0 and later; see the BBEdit LSP support page for complete details.

• Nova: R-Nova

Services Implemented

languageserver is still under active development, the following services have been implemented:

• textDocumentSync
• publishDiagnostics
• hoverProvider
• completionProvider
• completionItemResolve
• signatureHelpProvider
• definitionProvider
• referencesProvider
• documentHighlightProvider
• documentSymbolProvider
• workspaceSymbolProvider
• codeActionProvider
• codeLensProvider
• documentFormattingProvider
• documentRangeFormattingProvider
• documentOnTypeFormattingProvider
• renameProvider
• prepareRenameProvider
• documentLinkProvider
• documentLinkResolve
• colorProvider
• colorPresentation
• foldingRangeProvider
• selectionRangeProvider
• prepareCallHierarchy
• callHierarchyIncomingCalls
• callHierarchyOutgoingCalls
• prepareTypeHierarchy
• typeHierarchySupertypes
• typeHierarchySubtypes
• semanticTokens
• linkedEditingRange
• executeCommandProvider
• inlineValueProvider
• inlayHintProivder

Settings

languageserver exposes the following settings via LSP configuration.

settings	default	description
r.lsp.debug	false	increase verbosity for debug purpose
r.lsp.log_file	null	file to log debug messages, fallback to stderr if empty
r.lsp.diagnostics	true	enable file diagnostics via lintr
r.lsp.rich_documentation	true	rich documentation with enhanced markdown features
r.lsp.snippet_support	true	enable snippets in auto completion
r.lsp.max_completions	200	maximum number of completion items
r.lsp.lint_cache	false	toggle caching of lint results
r.lsp.server_capabilities	{}	override server capabilities defined in capabilities.R. See FAQ below.
r.lsp.link_file_size_limit	16384	maximum file size (in bytes) that supports document links

These settings could also specified in .Rprofile file via options(languageserver.<SETTING_NAME> = <VALUE>). For example,

options(languageserver.snippet_support = FALSE)

will turn off snippet support globally. LSP configuration settings are always overriden by options().

FAQ

Linters

With lintr v2.0.0, the linters can be specified by creating the .lintr file at the project or home directory. Details can be found at lintr documentation.

Customizing server capabilities

Server capabilities are defined in capabilities.R. Users could override the capabilities by specifying the LSP configuration setting server_capabilities or options(languageserver.server_capabilities) in .Rprofile. For example, to turn off definitionProvider, one could either use LSP configuration

"r": {
    "lsp": {
        "server_capabilities": {
            "definitionProvider": false
        }
    }
}

or R options

options(
    languageserver.server_capabilities = list(
        definitionProvider = FALSE
    )
)

Customizing formatting style

The language server uses styler to perform code formatting. It uses styler::tidyverse_style(indent_by = options$tabSize) as the default style where options is the formatting options.

The formatting style can be customized by specifying languageserver.formatting_style option which is supposed to be a function that accepts an options argument mentioned above. You could consider to put the code in .Rprofile.

styler::tidyverse_style provides numerous arguments to customize the formatting behavior. For example, to make it only work at indention scope:

options(languageserver.formatting_style = function(options) {
    styler::tidyverse_style(scope = "indention", indent_by = options$tabSize)
})

To disable assignment operator fix (replacing = with <-):

options(languageserver.formatting_style = function(options) {
    style <- styler::tidyverse_style(indent_by = options$tabSize)
    style$token$force_assignment_op <- NULL
    style
})

To further customize the formatting style, please refer to Customizing styler.