221 releases (112 stable)

new 1.71.23 May 28, 2024
1.71.21 Mar 24, 2024
1.71.19 Dec 14, 2023
1.71.15 Nov 5, 2023
0.6.10 Jul 31, 2019

#20 in Development tools

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598 downloads per month

MIT license



Cross Platform Rust Repl

You can try out IRust with no installation or setup (via Gitpod.io) by visiting https://gitpod.io/#https://github.com/sigmaSd/IRust

Keywords / Tips & Tricks

:help => print help, use :help full for the full version

:reset => reset repl

:show => show repl current code (optionally depends on rustfmt to format output)

:add <dep_list> => add dependencies also it accepts most cargo add arguments, for example you can import local dependencies with :add --path path_to_crate

:type <expression> => shows the expression type, example :type vec!(5)

:time <expression> => return the amount of time the expression took to execute. example: :time 5+4 :time my_fun(arg1,arg2)

:time_release <expression> => same as time command but with release mode

:load => load a rust file into the repl

:reload => reload the last specified file

:pop => remove last repl code line

:del <line_num> => remove a specific line from repl code (line count starts at 1 from the first expression statement)

:edit [editor] => edit internal buffer using an external editor, example: :edit micro. If no editor is specified then the one from the EDITOR environment variable is used (if set). Note some gui terminal requires using :sync command after the edit (vscode)

:sync sync the changes written after using :edit with a gui editor (vscode) to the repl

:cd => change current working directory

:color <key> <value> => change token highlight color at runtime, for the token list and value representation check the Theme section, exp: :color function red :color macro #ff12ab :color reset

:toolchain <value> => switch between toolchains, supported value are: stable, beta, nightly, default

:theme <value> => if used without arguments list currently installed themes, otherwise set irust to the given theme, see Themes section for more info

:check_statements true/false => If its set to true, irust will check each statemnt (input that ends with ;) with cargo_check before inserting it to the repl

:bench => run cargo bench

:asm <function> => shows assembly of the specified function, note that the function needs to be public, and there has to be no free standing statements/expressions (requires cargo-show-asm)

:executor <executor> => set the executor to be used by IRust, available options are: sync tokio async_std, by using an async executor, await becomes usable with no other modifications for async executors)

:evaluator <evaluator>> => set the evaluator statement, exmaple: :evaluator println!("{}",{$$}) the $$ will be replaced by IRust by the input code (the default evaluator uses debug formatting). To reset the evaluator to default you can use :evaluator reset

:scripts: => if invoked with no arguments it prints a list of detected scripts, if invoked with on argument it print that script info if it exits, if invoked with 2 arguments, it tries to activate/deactivate a script, example: :scripts Vim deactivate

:compile_time <on/off> => if set to on, IRust will print compiling time on each input, compile time includes rustc compiling + some IRust code (should be marginal)

:compile_mode <debug/release> => Sets how cargo will compile the code in release or debug mode

:main_result <value> => Change main result type, available options are Unit and Result (which is Result<(), Box<dyn std::error::Error>>), Using Result as type allows to use ? in the repl without any boilerplate

:dbg <expression> => Spawn rust-lldb/rust-gdb with (an optional expression), example: :dbg or :dbg fact(12), The debugger can be specified in the config file

:expand [function] => Shows the result of macro expansion, requires https://github.com/dtolnay/cargo-expand, function is optional, example fn b() { println!("42"); } then :expand b

:exit | :quit => Exit IRust immediately

$$ => Shell commands can be interpolated with rust code with '$$', for example: let a = $$ls -l$$;, this feature can be en/disabled via the config file

:: => run a shell command, example ::ls

You can use arrow keys to cycle through commands history.

You can disable all colors by setting NO_COLOR env variable.

To enable completion with tab via rust-analyzer, set enable_rust_analyzer to true in the config.


ctrl-l clear screen

ctrl-c clear line

ctrl-d exit if buffer is empty

ctrl-z [unix only] send IRust to the background

ctrl-r search history, hitting ctrl-r again continues searching the history backward, hitting ctrl-s searches the history forward

ctrl-left/right jump through words

HOME/END go to line start / line end

Tab/ShiftTab cycle through completion suggestions

Alt-Enter | ctrl-s add line break

ctrl-e force evaluation

ctrl-o->**[+-]key** Start recording a macro and saved on the specified key, if ctrl-o is clicked again the recording is stopped

ctrl-p->key Play a macro saved on the specified key

ctrl-u Undo

ctrl-y Redo

ctrl-x Delete current line

Cli commands

--help prints help message

--reset-config reset IRust configuration to default

If input is piped to IRust then it will evaluate it and exit, example: echo '"hello".chars()' | irust


IRust config file is located in:

Linux: /home/$USER/.config/irust/config.toml

Win: C:\Users\$USER\AppData\Roaming/irust/config.toml

Mac: /Users/$USER/Library/Preferences/irust/config.toml

default config:

  # history
  add_irust_cmd_to_history = true
  add_shell_cmd_to_history = false

  # colors
  ok_color = "Blue"
  eval_color = "White"
  irust_color = "DarkBlue"
  irust_warn_color = "Cyan"
  out_color = "Red"
  shell_color = "DarkYellow"
  err_color = "DarkRed"
  input_color = "Green"
  insert_color = "White"
  welcome_msg = ""
  welcome_color = "DarkBlue"

  # Rust analyzer
  ra_inline_suggestion_color = "Cyan"
  ra_suggestions_table_color = "Green"
  ra_selected_suggestion_color = "DarkRed"
  ra_max_suggestions = 5
  enable_rust_analyzer = false

  # other
  first_irust_run = false
  toolchain = "stable"
  check_statements = true
  auto_insert_semicolon = true
  #use last output by replacing the specified marker
  replace_marker = "$out"
  replace_output_with_marker = false
  # modify input prmopt
  input_prompt = "In: "
  output_prompt = "Out: "
  # activate scripting feature
  activate_scripting = false
  # select executor (Sync, Tokio, Asyncstd)
  executor = "Sync"
  evaluator = ["println!(\"{:?}\", {\n", "\n});"]
  compile_time = false
  main_result = "Unit"
  show_warnings = false
  edition = "E2021"
  debugger = "LLDB"
  shell_interpolate = true
  local_server = false
  local_server_adress = ""
  theme = "default"


Since release 1.66.0 IRust can now parse any theme file located under $config_dir/irust/themes and use it for the highlighting colors.

To select a theme, set its name in the irust config. for example to set themes/mytheme.toml set theme = "mytheme"

Colors can be specified as names ("red") or as hex representation ("#ff12ab").

Default theme file (default.toml):

  keyword = "magenta"
  keyword2 = "dark_red"
  function = "blue"
  type = "cyan"
  symbol = "red"
  macro = "dark_yellow"
  literal = "yellow"
  lifetime = "dark_magenta"
  comment = "dark_grey"
  const = "dark_green"
  ident = "white"


IRust automatically creates irust_prelude crate at xdg_data_dir/irust/irust_prelude, this crate is imported at startup, any changes to it (that are marked with pub) will be immediately reflected on the repl after saving.


IRust supports scripting, all over the code base there are hooks that scripts can react to and usually answer back to IRust with a command.
Check out SCRIPTS.md for more info.

Vim Plugin

For nvim you can use https://github.com/hkupty/iron.nvim (needs irust 1.67.4)

Old method:

Since version 1.60.0 IRust supports spawning a local server, by changing local_server to true in the configuration file.
This allows it to be controlled programmatically, which in turns allows writing vim plugins that uses this, see https://github.com/sigmaSd/irust-vim-plugin

Jupyter Notebook

Currently there is a barebone kernel that is easily installable see https://github.com/sigmaSd/IRust/blob/master/crates/irust_repl/README.md#jupyter-kernel for instructions


The IRust Book is intended to document a couple of tips and tricks https://sigmasd.github.io/irust_book


Automatic releases by github actions are uploaded here https://github.com/sigmaSd/irust/releases


  • cargo install irust
  • cargo binstall irust (using cargo-binstall)
  • There is also a flaptak package, its self contained , but have some limitations

Get it from FlatHub


cargo b --release

How It Works (random drawing ahead)



1- I want to hack on irust but dbg! overlaps with the output!!

Personaly I do this:

  • Run 2 terminals side by side
  • run tty in the first which should output something like /dev/pts/4
  • run cargo r 2>/dev/pts4 in the second

Now the dbg! statements are printed on the second terminal and the output in the first terminal is not messed up.



~126K SLoC