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

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 libuv1-dev r-base

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

The following editors are supported by installing the corresponding extensions:

• VS Code: vscode-R

• Atom: atom-ide-r

• Sublime Text: R-IDE

• NeoVim: NeoVim's LSP client with settings

  vim.lsp.config['r_language_server'] = {
  	settings = {
  		filetypes = { "r", "rmd" },
  	},
  }
  vim.api.nvim_create_autocmd("FileType", {
  	pattern = { "r", "rmd" },
  	callback = function()
  		vim.lsp.start(vim.lsp.config["r_language_server"])
  	end,
  }

  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" : [ "--no-echo", "-e", "languageserver::run()"],
            "filetypes" : ["r"]
        }
    }

• Emacs: eglot-mode (native LSP client)

  (use-package ess :ensure t)
  (add-hook 'ess-r-mode-hook 'eglot-ensure)

  To check if it is working, open an R file, place the cursor on a line and run M-x ess-eval-line.

• 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

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
• inlayHintProvider

Inline values are a debugger-facing feature rather than normal editor annotations. When execution is paused, a compatible editor and debug adapter request variable lookup ranges from the language server, evaluate them in the selected stack frame, and render the resulting values beside the source. They have no visible effect when the client or R debug adapter does not request textDocument/inlineValue.

languageserver exposes the following settings via LSP configuration.

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().

Project indexing is deliberately two-tiered. Package R/ files, open files, and the transitive dependencies of static source() or sys.source() calls receive full semantic parsing. Other scripts receive only a lightweight symbol and source-call summary, so they appear in workspace symbol search without polluting completion, definition, references, or rename in unrelated scripts. Static paths built from string literals, file.path(), and here::here() are recognized; project code is never executed to resolve a path.

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.

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
    )
)

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.