radian: A 21 century R console

radian is an alternative console for the R program with multiline editing and rich syntax highlight. One would consider radian as a ipython clone for R, though its design is more aligned to julia. If you are looking for a Rust-based alternative, check out arf by @eitsupi.

Features

• Cross-platform: runs on Windows, macOS, and Linux
• Shell mode: hit ; to enter and <backspace> to leave
• reticulate Python REPL mode: hit ~ to enter
• Improved R prompt and reticulate Python prompt:
  • Multiline editing
  • Syntax highlighting
  • Auto-completion (reticulate auto-completion uses jedi)
• Native Unicode / UTF-8 support (including Windows with R >= 4.2)
• LaTeX symbol completion (e.g., \alpha + <tab>)
• Auto-matching parentheses and quotes
• Bracketed paste mode
• Emacs and Vi editing modes
• Automatically adjusts to terminal width
• Reads more than 4096 bytes per line

Installation

Requirements

• R (>= 4.2.0): Download from https://cran.r-project.org (built with shared library libR.so / libR.dylib / R.dll).
• Python (>= 3.10): Download from https://www.python.org/downloads/.

Installing radian via pipx or uv is recommended:

# install released version via pipx (or `uv tool install radian`)
pipx install radian

# or install the development version
pipx install git+https://github.com/randy3k/radian

# launch radian
radian

Unix Alias

You can alias r to radian in ~/.bashrc or ~/.zshrc so that r launches radian while R still opens the traditional R console (useful for commands like R CMD build):

alias r="radian"

Settings

radian can be customized via R options() in any of the following profile files:

• $XDG_CONFIG_HOME/radian/profile or $HOME/.config/radian/profile (Unix)
• %USERPROFILE%/radian/profile (Windows)
• $HOME/.radian_profile (Unix)
• %USERPROFILE%/.radian_profile (Windows)
• .radian_profile in the current working directory

Note

Specifying radian.* options in .Rprofile also works, but is not recommended because .Rprofile is skipped in --vanilla mode and may not be loaded in project-specific renv / packrat environments.

# Example ~/.radian_profile — only specify the options you want to customize
options(
    radian.color_scheme = "native",
    radian.editing_mode = "emacs"
)

Option	Default	Description
radian.color_scheme	"native"	Color scheme for syntax highlighting (see Pygments styles)
radian.editing_mode	"emacs"	Key binding mode: "emacs" or "vi"
radian.emacs_bindings_in_vi_insert_mode	FALSE	Enable common Emacs key bindings while in Vi insert mode
radian.show_vi_mode_prompt	TRUE	Show Vi mode indicator when radian.editing_mode = "vi"
radian.vi_mode_prompt	"\033[34m[{}]\033[0m "	Format string (or named list list(ins = ..., nav = ...)) for the Vi mode indicator
radian.prompt	"\033[34mr$>\033[0m "	Custom R prompt string
radian.shell_prompt	"\033[31m#!>\033[0m "	Custom shell mode prompt string
radian.browse_prompt	"\033[33mBrowse[{}]>\033[0m "	Custom debug browser prompt string
radian.stderr_format	"\033[31m{}\033[0m"	Format string for standard error output
radian.insert_new_line	TRUE	Insert a blank newline between prompts
radian.indent_lines	TRUE	Indent continuation lines in multiline prompt
radian.auto_indentation	TRUE	Auto-indent new lines and curly braces
radian.tab_size	4	Number of spaces per indentation level
radian.auto_match	TRUE	Automatically match brackets and quotes
radian.highlight_matching_bracket	FALSE	Highlight matching brackets around the cursor
radian.auto_width	TRUE	Automatically adjust R width option when the terminal resizes
radian.complete_while_typing	TRUE	Show completion menu automatically while typing
radian.completion_prefix_length	2	Minimum prefix length to trigger auto-completion
radian.completion_timeout	0.15	Timeout in seconds to cancel slow completions (0 to disable)
radian.completion_adding_spaces_around_equals	TRUE	Add spaces around = in function argument completions
radian.auto_suggest	FALSE	Enable prompt_toolkit auto-suggestion from history (experimental)
radian.history_size	20000	Maximum number of history entries to keep
radian.global_history_file	"~/.radian_history"	Path to the global history file (environment variables and ~ are expanded)
radian.local_history_file	".radian_history"	Filename for project-local history (used instead of global history if present in the working directory)
radian.history_search_no_duplicates	FALSE	Skip duplicate entries during incremental history search (Ctrl-R / Ctrl-S)
radian.history_search_ignore_case	FALSE	Perform case-insensitive incremental history search
radian.history_ignore_browser_commands	TRUE	Do not save short debug browser commands (such as n, s, c, Q) in history
radian.enable_reticulate_prompt	TRUE	Enable reticulate Python REPL mode triggered by ~

Custom Key Bindings

You can define custom Escape (or Alt) and Ctrl shortcuts in your profile. Note that some Ctrl keys (m, i, h, d, c) are reserved by the terminal and cannot be remapped.

# Example: `Esc` + `-` (or `Alt` + `-` if Alt sends Escape) inserts ` <- `,
# and `Ctrl` + `Right` inserts ` %>% `
options(
    radian.escape_key_map = list(
        list(key = "-", value = " <- ")
    ),
    radian.ctrl_key_map = list(
        list(key = "right", value = " %>% ")
    )
)

FAQ

How do I switch to a different R version or specify the R binary?

You can select which R installation radian uses in several ways:

• Pass --r-binary: radian --r-binary=/path/to/R
• Expose the desired R binary first on PATH
• Set R_BINARY=/path/to/R
• Set R_HOME to the output of R.home() (for example, env R_HOME=/usr/local/lib/R radian)

Why can't I switch the Python runtime in reticulate?

radian itself runs inside a Python process, so reticulate is bound to the Python runtime hosting radian (NOTE: Python version was forced by the current process). To use radian with a different Python environment, install radian in that environment.

How do I enable reticulate auto-completions?

Install jedi in the same Python environment as radian (e.g., pipx inject radian jedi or pip install jedi).

Cannot find R shared library (libR.so / libR.dylib / R.dll)

Make sure R was compiled with the shared library enabled. When building R from source on Linux, pass ./configure --enable-R-shlib (and run make clean before rebuilding if previously compiled without it).

How do I use a local history file?

radian stores history in .radian_history (separate from .Rhistory). If a .radian_history file exists in the working directory, radian uses it automatically; otherwise it uses ~/.radian_history. You can override this with radian --local-history, radian --global-history, or radian --no-history.

Does radian slow down R code?

radian only provides the interactive console frontend; R's evaluation loop is identical to the standard R console. However, fork-based parallelism (parallel::mclapply or future::plan("multicore")) is not recommended from an embedded R/Python process; prefer socket/multisession workers (future::plan("multisession")).

Nvim-R configuration

Add the following to your Vim/Neovim configuration:

let R_app = "radian"
let R_cmd = "R"
let R_hl_term = 0
let R_args = []  " if you had set any
let R_bracketed_paste = 1

Prompt not shown inside a Docker container

This can happen when the container's PTY size is uninitialized. Run stty size to check, or pass $COLUMNS and $LINES when attaching:

docker exec -it <container> bash -c "stty cols $COLUMNS rows $LINES && bash"

Why called radian?

radian is powered by (π)thon.

Credits

radian wouldn't be possible without the creative work prompt_toolkit by Jonathan Slenders.