r3bl_tuify

Why R3BL?

R3BL TUI library & suite of apps focused on developer productivity

We are working on building command line apps in Rust which have rich text user interfaces (TUI). We want to lean into the terminal as a place of productivity, and build all kinds of awesome apps for it.

1. 🔮 Instead of just building one app, we are building a library to enable any kind of rich TUI development w/ a twist: taking concepts that work really well for the frontend mobile and web development world and re-imagining them for TUI & Rust.

   • Taking inspiration from things like React, SolidJS, Elm, iced-rs, Jetpack Compose, JSX, CSS, but making everything async (so they can be run in parallel & concurrent via Tokio).
   • Even the thread running the main event loop doesn't block since it is async.
   • Using proc macros to create DSLs to implement something inspired by CSS & JSX.

2. 🌎 We are building apps to enhance developer productivity & workflows.

   • The idea here is not to rebuild tmux in Rust (separate processes mux'd onto a single terminal window). Rather it is to build a set of integrated "apps" (or "tasks") that run in the same process that renders to one terminal window.
   • Inside of this terminal window, we can implement things like "app" switching, routing, tiling layout, stacking layout, etc. so that we can manage a lot of TUI apps (which are tightly integrated) that are running in the same process, in the same window. So you can imagine that all these "app"s have shared application state. Each "app" may also have its own local application state.
   • Here are some examples of the types of "app"s we plan to build (for which this infrastructure acts as the open source engine):
     1. Multi user text editors w/ syntax highlighting.
     2. Integrations w/ github issues.
     3. Integrations w/ calendar, email, contacts APIs.

All the crates in the r3bl-open-core repo provide lots of useful functionality to help you build TUI (text user interface) apps, along w/ general niceties & ergonomics that all Rustaceans 🦀 can enjoy 🎉.

Table of contents

• Introduction
• Changelog
• Learn how these crates are built, provide feedback
• How to use it as a library?
• APIs
  • select_from_list
  • select_from_list_with_multi_line_header
• How to use it as a binary?
  • Interactive user experience
  • Paths
• Style the components
  • Choose one of the 3 built-in styles
  • Create your style
• Build, run, test tasks
  • Prerequisites
  • Nushell scripts to build, run, test, etc.
• References

Introduction

r3bl_tuify is a Rust crate that allows you to add simple interactivity to your CLI app.

r3bl_tuify crate can be used in two ways:

1. As a library. This is useful if you want to add simple interactivity to your CLI app written in Rust. You can see an example of this in the examples folder in the main_interactive.rs file. You can run it using cargo run --example main_interactive.

2. As a binary. This is useful if you want to use this crate as a command line tool. The binary target is called rt.

Changelog

Please check out the changelog to see how the library has evolved over time.

Learn how these crates are built, provide feedback

To learn how we built this crate, please take a look at the following resources.

• If you like consuming video content, here's our YT channel. Please consider subscribing.
• If you like consuming written content, here's our developer site. Please consider subscribing to our newsletter.
• If you have questions, please join our discord server.

How to use it as a library?

Here's a demo of the library target of this crate in action.

To install the crate as a library, add the following to your Cargo.toml file:

[dependencies]
r3bl_tuify = "*" # Get the latest version at the time you get this.
r3bl_core = "*" # Get the latest version at the time you get this.

The following example illustrates how you can use this as a library. The function that does the work of rendering the UI is called [select_from_list]. It takes a list of items and returns the selected item or items (depending on the selection mode). If the user does not select anything, it returns None. The function also takes the maximum height and width of the display, and the selection mode (single select or multiple select).

It works on macOS, Linux, and Windows. And is aware of the terminal color output limitations of each. For eg, it uses Windows API on Windows for keyboard input. And on macOS Terminal.app it restricts color output to a 256 color palette.

use r3bl_core::*;
use r3bl_tuify::*;
use std::io::Result;

fn main() -> Result<()> {
    // Get display size.
    let max_width_col_count: usize = get_size().map(|it| it.col_count).unwrap_or(ch!(80)).into();
    let max_height_row_count: usize = 5;

    let user_input = select_from_list(
        "Select an item".to_string(),
        [
            "item 1", "item 2", "item 3", "item 4", "item 5", "item 6", "item 7", "item 8",
            "item 9", "item 10",
        ]
        .iter()
        .map(|it| it.to_string())
        .collect(),
        max_height_row_count,
        max_width_col_count,
        SelectionMode::Single,
        StyleSheet::default(),
    );

    match &user_input {
        Some(it) => {
            println!("User selected: {:?}", it);
        }
        None => println!("User did not select anything"),
    }

    Ok(())
}

APIs

We provide 2 APIs:

• [select_from_list]: Use this API if you want to display a list of items with a single line header.
• [select_from_list_with_multi_line_header]: Use this API if you want to display a list of items with a multi line header.

select_from_list

Use this API if you want to display a list of items with a single line header.

[select_from_list] code example:

use r3bl_core::*;
use r3bl_tuify::*;
use std::io::Result;

fn main() -> Result<()> {
    // Get display size.
    let max_height_row_count: usize = 5;
    let user_input = select_from_list(
        "Select an item".to_string(),
        [
            "item 1", "item 2", "item 3", "item 4", "item 5", "item 6", "item 7", "item 8",
            "item 9", "item 10",
        ]
        .iter()
        .map(|it| it.to_string())
        .collect(),
        max_height_row_count,
        0,
        SelectionMode::Single,
        StyleSheet::default(),
    );

    match &user_input {
        Some(it) => {
            println!("User selected: {:?}", it);
        }
        None => println!("User did not select anything"),
    }

    Ok(())
}

select_from_list_with_multi_line_header

Use the select_from_list_with_multi_line_header API if you want to display a list of items with a multi line header. The first 5 lines are all part of the multi line header.

[select_from_list_with_multi_line_header] code example:

use std::{io::Result, vec};

use r3bl_ansi_color::{AnsiStyledText, Color, Style as RStyle};
use r3bl_core::*;
use r3bl_tuify::{
    components::style::StyleSheet,
    select_from_list_with_multi_line_header,
    SelectionMode,
};

fn multi_select_instructions() -> Vec<Vec<AnsiStyledText<'static>>> {
    let up_and_down = AnsiStyledText {
        text: " Up or down:",
        style: &[
            RStyle::Foreground(Color::Rgb(9, 238, 211)),
            RStyle::Background(Color::Rgb(14, 17, 23)),
        ],
    };
    let navigate = AnsiStyledText {
        text: "     navigate",
        style: &[
            RStyle::Foreground(Color::Rgb(94, 103, 111)),
            RStyle::Background(Color::Rgb(14, 17, 23)),
        ],
    };

    let line_1 = vec![up_and_down, navigate];

    let space = AnsiStyledText {
        text: " Space:",
        style: &[
            RStyle::Foreground(Color::Rgb(255, 216, 9)),
            RStyle::Background(Color::Rgb(14, 17, 23)),
        ],
    };
    let select = AnsiStyledText {
        text: "          select or deselect item",
        style: &[
            RStyle::Foreground(Color::Rgb(94, 103, 111)),
            RStyle::Background(Color::Rgb(14, 17, 23)),
        ],
    };

    let line_2 = vec![space, select];

    let esc = AnsiStyledText {
        text: " Esc or Ctrl+C:",
        style: &[
            RStyle::Foreground(Color::Rgb(255, 132, 18)),
            RStyle::Background(Color::Rgb(14, 17, 23)),
        ],
    };
    let exit = AnsiStyledText {
        text: "  exit program",
        style: &[
            RStyle::Foreground(Color::Rgb(94, 103, 111)),
            RStyle::Background(Color::Rgb(14, 17, 23)),
        ],
    };

    let line_3 = vec![esc, exit];
    let return_key = AnsiStyledText {
        text: " Return:",
        style: &[
            RStyle::Foreground(Color::Rgb(234, 0, 196)),
            RStyle::Background(Color::Rgb(14, 17, 23)),
        ],
    };
    let confirm = AnsiStyledText {
        text: "         confirm selection",
        style: &[
            RStyle::Foreground(Color::Rgb(94, 103, 111)),
            RStyle::Background(Color::Rgb(14, 17, 23)),
        ],
    };
    let line_4 = vec![return_key, confirm];
    vec![line_1, line_2, line_3, line_4]
}

fn main() -> Result<()> {
   let header = AnsiStyledText {
        text: " Please select one or more items. This is a really long heading that just keeps going and if your terminal viewport is small enough, this heading will be clipped",
        style: &[
            RStyle::Foreground(Color::Rgb(171, 204, 242)),
            RStyle::Background(Color::Rgb(31, 36, 46)),
        ],
    };

    let mut instructions_and_header: Vec<Vec<AnsiStyledText>> = multi_select_instructions();
    instructions_and_header.push(vec![header]);

    let user_input = select_from_list_with_multi_line_header(
        instructions_and_header,
        [
            "item 1 of 13",
            "item 2 of 13",
            "item 3 of 13",
            "item 4 of 13",
            "item 5 of 13",
            "item 6 of 13",
            "item 7 of 13",
            "item 8 of 13",
            "item 9 of 13",
            "item 10 of 13",
            "item 11 of 13",
            "item 12 of 13",
            "item 13 of 13",
        ]
        .iter()
        .map(|it| it.to_string())
        .collect(),
        Some(6),
        None,
        SelectionMode::Multiple,
        StyleSheet::default(),
    );
    match &user_input {
        Some(it) => {
            println!("User selected: {:?}", it);
        }
        None => println!("User did not select anything"),
    }
   Ok(())
}

How to use it as a binary?

Here's a demo of the binary target of this crate in action.

You can install the binary using cargo install r3bl_tuify (from crates.io). Or cargo install --path . from source. rt is a command line tool that allows you to select one of the options from the list that is passed into it via stdin. It supports both stdin and stdout piping.

Here are the command line arguments that it accepts:

1. -s or --selection-mode - Allows you to select the selection mode. There are two options: single and multiple.
2. -c or --command-to-run-with-selection - Allows you to specify the command to run with the selected item. For example "echo foo \'%\'" simply prints each selected item.
3. -t or --tui-height - Optionally allows you to set the height of the TUI. The default is 5.

Interactive user experience

Typically a CLI app is not interactive. You can pass commands, subcommands, options, and arguments to it, but if you get something wrong, then you get an error and have to start all over again. This "conversation" style interface might require a lot of trial and error to get the desired result.

The following is an example of using the binary with many subcommands, options, and arguments.

cat TODO.todo | cargo run -- select-from-list \
    --selection-mode single \
    --command-to-run-with-each-selection "echo %"

Here's a video of this in action.

What does this do?

1. cat TODO.todo - prints the contents of the TODO.todo file to stdout.
2. | - pipes the output of the previous command to the next command, which is rt (ie, the binary target of this crate).
3. cargo run -- - runs the rt debug binary in the target folder.
4. select-from-list - runs the rt binary with the select-from-list subcommand. This subcommand requires 2 arguments: --selection-mode and --command-to-run-with-each-selection. Whew! This is getting long!
5. --selection-mode single - sets the selection mode to single. This means that the user can only select one item from the list. What list? The list that is piped in from the previous command (ie, cat TODO.todo).
6. --command-to-run-with-each-selection "echo %" - sets the command to run with each selection. In this case, it is echo %. The % is a placeholder for the selected item. So if the user selects item 1, then the command that will be run is echo item 1. The echo command simply prints the selected item to stdout.

Now that is a lot to remember. It is helpful to use clap to provide nice command line help but that are still quite a few things that you have to get right for this command to work.

It doesn't have to be this way. The binary can be interactive along with the use of clap to specify some of the subcommands, and arguments. It doesn't have to be an all or nothing approach. We can have the best of both worlds. The following videos illustrate what happens when:

1. --selection-mode and --command-to-run-with-each-selection are not passed in the command line.

   cat TODO.todo | cargo run -- select-from-list
   

   Here are the 3 scenarios that can happen:

   • The user first chooses single selection mode (using a list selection component), and then types in echo % in the terminal, as the command to run with each selection. This is an interactive scenario since the user has to provide 2 pieces of information: the selection mode, and the command to run with each selection. They didn't provide this upfront when they ran the command.

   • Another scenario is that the user does not provide the required information even when prompted interactively. In this scenario, the program exits with an error and help message.

     Here they don't provide what selection-mode they want. And they don't provide what command-to-run-with-each-selection they want. Without this information the program can't continue, so it exits and provides some help message.

2. --selection-mode is not passed in the command line. So it only interactively prompts the user for this piece of information. Similarly, if the user does not provide this information, the app exits and provides a help message.

   cat TODO.todo | cargo run -- select-from-list --command-to-run-with-each-selection "echo %"
   

3. --command-to-run-with-each-selection is not passed in the command line. So it only interactively prompts the user for this piece of information. Similarly, if the user does not provide this information, the app exits and provides a help message.

   cat TODO.todo | cargo run -- select-from-list --selection-mode single
   

Paths

There are a lot of different execution paths that you can take with this relatively simple program. Here is a list.

• Happy paths:

  1. rt - prints help.
  2. cat Cargo.toml | rt -s single -c "echo foo \'%\'" - stdin is piped in, and it prints the user selected option to stdout.
  3. cat Cargo.toml | rt -s multiple -c "echo foo \'%\'" - stdin is piped in, and it prints the user selected option to stdout.

• Unhappy paths (stdin is not piped in and, or stdout is piped out):

  1. rt -s single - expects stdin to be piped in, and prints help.
  2. rt -s multiple - expects stdin to be piped in, and prints help.
  3. ls -la | rt -s single | xargs -0 - does not expect stdout to be piped out, and prints help.
  4. ls -la | rt -s multiple | xargs -0 - does not expect stdout to be piped out, and prints help.

Due to how unix pipes are implemented, it is not possible to pipe the stdout of this command to anything else. Unix pipes are non-blocking. So there is no way to stop the pipe "midway". This is why rt displays an error when the stdout is piped out. It is not possible to pipe the stdout of rt to another command. Instead, the rt binary simply takes a command that will run after the user has made their selection. Using the selected item(s) and applying them to this command.

Style the components

Choose one of the 3 built-in styles

Built-in styles are called default, sea_foam_style, and hot_pink_style. You can find them in the style.rs file (tuify/src/components/style.rs).

Default style:

sea_foam_style:

hot_pink_style:

To use one of the built-in styles, simply pass it as an argument to the select_from_list function.

use r3bl_core::*;
use r3bl_tuify::*;
use std::io::Result;

fn main() -> Result<()> {
    // 🎨 Uncomment the lines below to choose the other 2 built-in styles.
    // let default_style = StyleSheet::default();
    // let hot_pink_style = StyleSheet::hot_pink_style();
    let sea_foam_style = StyleSheet::sea_foam_style();

    let max_width_col_count: usize = get_size().map(|it| it.col_count).unwrap_or(ch!(80)).into();
    let max_height_row_count: usize = 5;

    let user_input = select_from_list(
        "Select an item".to_string(),
        [
            "item 1", "item 2", "item 3", "item 4", "item 5", "item 6", "item 7", "item 8",
            "item 9", "item 10",
        ]
        .iter()
        .map(|it| it.to_string())
        .collect(),
        max_height_row_count,
        max_width_col_count,
        SelectionMode::Single,
        sea_foam_style,  // 🖌️ or default_style or hot_pink_style
    );

    match &user_input {
        Some(it) => {
            println!("User selected: {:?}", it);
        }
        None => println!("User did not select anything"),
    }

    Ok(())
}

Create your style

To create your style, you need to create a StyleSheet struct and pass it as an argument to the select_from_list function.

use std::io::Result;
use r3bl_ansi_color::{AnsiStyledText, Color};
use r3bl_tuify::{components::style::{Style, StyleSheet},
                select_from_list,
                SelectionMode};

fn main() -> Result<()> {
   // This is how you can define your custom style.
   // For each Style struct, you can define different style overrides.
   // Please take a look at the Style struct to see what you can override.
   let my_custom_style = StyleSheet {
      focused_and_selected_style: Style {
            fg_color: Color::Rgb(255, 244, 0),
            bg_color: Color::Rgb(15, 32, 66),
            ..Style::default()
      },
      focused_style: Style {
            fg_color: Color::Rgb(255, 244, 0),
            ..Style::default()
      },
      unselected_style: Style { ..Style::default() },
      selected_style: Style {
            fg_color: Color::Rgb(203, 170, 250),
            bg_color: Color::Rgb(15, 32, 66),
            ..Style::default()
      },
      header_style: Style {
            fg_color: Color::Rgb(171, 204, 242),
            bg_color: Color::Rgb(31, 36, 46),
            ..Style::default()
      },
   };

   // Then pass `my_custom_style` as the last argument to the `select_from_list` function.
   let user_input = select_from_list(
      "Multiple select".to_string(),
      ["item 1 of 3", "item 2 of 3", "item 3 of 3"]
         .iter()
         .map(|it| it.to_string())
         .collect(),
      6, // max_height_row_count
      80, // max_width_col_count
      SelectionMode::Multiple,
      my_custom_style,
   );

   match &user_input {
      Some(it) => {
         println!("User selected: {:?}", it);
      }
      None => println!("User did not select anything"),
   }
   Ok(())
}

Build, run, test tasks

Prerequisites

🌠 For these to work you have to install the Rust toolchain, nu, cargo-watch, bat, and flamegraph on your system. Here are the instructions:

1. Install the Rust toolchain using rustup by following the instructions here.
2. Install cargo-watch using cargo install cargo-watch.
3. Install flamegraph using cargo install flamegraph.
4. Install bat using cargo install bat.
5. Install nu shell on your system using cargo install nu. It is available for Linux, macOS, and Windows.

Nushell scripts to build, run, test, etc.

Go to the tuify folder and run the commands below. These commands are defined in the ./run folder.

The following commands will watch for changes in the source folder and re-run:

There's also a run script at the top level folder of the repo. It is intended to be used in a CI/CD environment w/ all the required arguments supplied or in interactive mode, where the user will be prompted for input.

References

CLI UX guidelines:

• Handling Arguments
• Configuration
• Hierarchical Config
• Hierarchical Config
• Clap Derive Overview
• Command Line Interface Guidelines

ANSI escape codes:

• ANSI Escape Codes Notes
• ANSI Escape Code - Wikipedia
• ASCII Table
• Xterm 256 Color Chart
• 256 Colors Cheat Sheet
• List of ANSI Color Escape Sequences - Stack Overflow
• Color Metric

License: Apache-2.0