irust 1.7.1

Cross Platform Rust Repl
irust-1.7.1 is not a library.


Cross Platform Rust Repl

Keywords / Tips & Tricks

:help => print help

:reset => reset repl

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

:add <dep_list> => add dependencies (requires cargo-edit) also it accepts most cargo-edit arguments

: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, 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, nighty

: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 (requires cargo-asm)

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

You can use arrow keys to cycle through commands history


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 auto-completion suggestions (requires racer)

Alt-Enter add line break

ctrl-e force evaluation

Cli commands

--help prints help message

--reset-config reset IRust configuration to default


IRust config file is located in:

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

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

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

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"

  # racer
  racer_inline_suggestion_color = "Cyan"
  racer_suggestions_table_color = "Green"
  racer_selected_suggestion_color = "DarkRed"
  racer_max_suggestions = 5
  enable_racer = true

  # 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


Since release 0.8.9 IRust can now parse a theme file located on $config_dir/irust/theme and use it for the highlighting colors.

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

Default theme file:

  keyword = "magenta"
  keyword2 = "dark_red"
  function = "blue"
  type = "cyan"
  number = "dark_yellow"
  symbol = "red"
  macro = "dark_yellow"
  string_literal = "yellow"
  character = "green"
  lifetime = "dark_magenta"
  comment = "dark_grey"
  const = "dark_green"
  x = "white"


Since release 1.7.0 IRust has a new script mechanism codename script2, the old method is still available but deprecated for now see below if you still want to use it.

The main advantages are:

  • No unsafe, scripts should not be able to break IRust (not 100%)
  • Hot reloading! recompiling a script will immediatly take effect on IRust without restarting

To activate this feature, set activate_scripting2 to true in the configuration file. (it will take precedence over script1 if its set to true)

Now IRust will look in $config/irust/script2 for executables.

It will launch them when required and comminucate via stdin/stdout (with bincode as a relay).

The executables need to have the following properties:

Name Input Output What it should do
input_prompt irust_api::GlobalVariables String return the input prompt value as a string
output_prompt irust_api::GlobalVariables String return the output prompt value as a string
while_compiling irust_api::GlobalVariables () do arbitrary things while IRust is compiling an expression (print some waiting animation for example)

All scripts should add bincode and irust_api as dependecy

For more concrete example see scripts_examples directory

Old method

Since release 1.5.0 IRust introduced scripting feature.

To activate it, set activate_scripting to true in the configuration file.

Now IRust will create a cargo project named script located at $config/irust/script

This project has a default template, that showcases the available features.

Currently Supported functions (see example):

pub extern "C" fn input_prompt(global_varibales: &GlobalVariables) -> *mut c_char
pub extern "C" fn output_prompt(global_varibales: &GlobalVariables) -> *mut c_char

Important points:

  • Scripting is currently unsafe, using it incorrectly will cause IRust to crash or segfault
  • Scripts have a higher precedence then options (for example prompt functions will override the prompt set in the configuration)


/// This script prints an input/output prompt with the number of the
/// evaluation prefixed to it
use std::{ffi::CString, os::raw::c_char, path::PathBuf};

// the signature must be this
pub struct GlobalVariables {
    // Current directory that IRust is in
    _current_working_dir: PathBuf,
    // Previous directory that IRust was in, this current directory can change if the user uses the `:cd` command
    _previous_working_dir: PathBuf,
    // Last path to a rust file loaded with `:load` command
    _last_loaded_code_path: Option<PathBuf>,
    /// Last successful printed output
    _last_output: Option<String>,
    /// A variable that increases with each input/output cycle
    operation_number: usize,

// the signature must be this
pub extern "C" fn input_prompt(global_varibales: &GlobalVariables) -> *mut c_char {
    // Default script
    CString::new(format!("In [{}]: ", global_varibales.operation_number))

// the signature must be this
pub extern "C" fn output_prompt(global_varibales: &GlobalVariables) -> *mut c_char {
    // Default script
    CString::new(format!("Out[{}]: ", global_varibales.operation_number))


Automatic releases by github actions are uploaded here


cargo b --release


1- Why is autocompletion not working

-> you need racer installed and configured correctly
    cargo +nightly install racer
    rustup component add rust-src

2- Racer fails to build

You can try rustup update --force

3- 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.