coal 0.1.0

Composable utilities for Dart command-line apps.

Coal

Composable utilities for Dart command-line apps.

Coal is not a CLI framework. It provides focused helpers that can be used with plain Dart CLIs or existing command packages.

Modules

Entry	Description
package:coal/args.dart	Lightweight command-line argument parsing.
package:coal/keypass.dart	Terminal key sequence decoding and binding dispatch.
package:coal/prompt.dart	Basic text prompt flow for terminal CLIs.
package:coal/prompt_utils.dart	Reusable prompt helpers for common CLI questions.
package:coal/readline.dart	Interactive line input with editing keys and history.
package:coal/utils.dart	ANSI escape-code and terminal text helpers.
package:coal/tab.dart	Shell completion definitions and script generation.
package:coal/tab/args.dart	Adapter for package:args CommandRunner apps.

Installation

dart pub add coal

Keypass

Decode complete terminal key sequences and dispatch key bindings:

import 'package:coal/keypass.dart';

final keys = Keypass();

keys.bind('ctrl+c', (event) => print('cancel'));
keys.bind('up', (event) => print('history up'));

keys.handleSequence('\x03'); // ctrl+c
keys.handleSequence('\x1b[A'); // up

Prompt

Ask for a text value with a basic prompt lifecycle:

import 'package:coal/prompt.dart';

Future<void> main() async {
  final prompt = Prompt.stdio();

  try {
    final name = await prompt.text('Name', defaultValue: 'anonymous');
    print('Hello, ${name ?? 'cancelled'}');
  } finally {
    await prompt.close();
  }
}

Prompt Utils

Use common prompt helpers on top of Prompt:

import 'package:coal/prompt.dart';
import 'package:coal/prompt_utils.dart';

Future<void> main() async {
  final prompt = Prompt.stdio();

  try {
    final publish = await prompt.confirm('Publish?', defaultValue: false);
    print(publish == true ? 'confirmed' : 'skipped');
  } finally {
    await prompt.close();
  }
}

Readline

Read one edited line from a terminal:

import 'package:coal/readline.dart';

Future<void> main() async {
  final readline = Readline.stdio();

  try {
    final name = await readline.readLine(prompt: 'Name: ');
    print('Hello, ${name ?? 'anonymous'}');
  } finally {
    await readline.close();
  }
}

<TAB>

Core

Define a completion tree and print shell scripts from your CLI:

import 'package:coal/tab.dart';

final tab = Tab();
final complete = tab.command('complete', '<TAB> autocompletion');

complete.argument('shell', (complete, _) {
  complete('bash', 'Setup bash shell completion');
  complete('zsh', 'Setup zsh shell completion');
  complete('fish', 'Setup fish shell completion');
  complete('powershell', 'Setup powershell shell completion');
});

See the runnable <TAB> example.

Completion scripts are synced from upstream Cobra behavior and covered by script contract tests. Maintainer sync and test details live in TAB Maintenance.

Dart CLI Completion

Install Coal globally and load completion for the Dart SDK command:

dart pub global activate coal
source <(coal tab dart bash)
dart <TAB>

Current-session setup:

# bash, with bash-completion loaded
source <(coal tab dart bash)

# zsh, after compinit
source <(coal tab dart zsh)

# fish
coal tab dart fish | source

# powershell
coal tab dart powershell | Out-String | Invoke-Expression

Persistent setup examples:

# bash
coal tab dart bash > ~/.dart-completion.bash
printf '\nsource ~/.dart-completion.bash\n' >> ~/.bashrc

# zsh
coal tab dart zsh > ~/.dart-completion.zsh
printf '\nsource ~/.dart-completion.zsh\n' >> ~/.zshrc

# fish
coal tab dart fish > ~/.config/fish/completions/dart.fish

coal tab dart powershell > $HOME\.dart-completion.ps1
Add-Content -Path $PROFILE -Value '. $HOME\.dart-completion.ps1'

Args Parser

Parse raw command-line tokens into a JSON-friendly argument tree:

import 'package:coal/args.dart';

const input = [
  '--a=1',
  '-b',
  '--bool',
  '--no-boop',
  '--multi=foo',
  '--multi=baz',
  '-xyz',
];
final args = Args.parse(input, list: ['multi']);

print(args.toJson());

{
  "a": 1,
  "b": true,
  "bool": true,
  "boop": false,
  "multi": ["foo", "baz"],
  "x": true,
  "y": true,
  "z": true
}

ANSI Utility

Generate ANSI escape codes and measure or wrap terminal text:

• Clear: Clear screen utilities.
• Cursor: Cursor manipulation utilities.
• Erase: Text erasing utilities.
• Scroll: Screen scrolling utilities.
• Text: Text styling and manipulation utilities.

Clear

Name	Description
clearScreen	Clear the terminal screen.

Cursor

Name	Description
cursorUp()	Move the cursor up by count lines.
cursorDown()	Move the cursor down by count lines.
cursorForward()	Move the cursor forward by count columns.
cursorBackward()	Move the cursor backward by count columns.
cursorNextLine()	Move the cursor to the next line by count lines.
cursorPrevLine()	Move the cursor to the previous line by count lines.
cursorTo()	Move the cursor to the specified position.
cursorMove()	Move the cursor by x columns and y lines.
cursorShow	Show the cursor.
cursorHide	Hide the cursor.
cursorSave	Save the cursor position.
cursorRestore	Restore the cursor position.
cursorLeft	Move the cursor to the first column.

Erase

Name	Description
eraseScreen	Erase the entire screen.
eraseLine	Erase the current line.
eraseLineStart	Erase from the current cursor position to the beginning of the line.
eraseLineEnd	Erase from the current cursor position to the end of the line.
eraseUp()	Erase count lines above the current cursor position.
eraseDown()	Erase count lines below the current cursor position.
eraseLines()	Erase count lines above and below the current cursor position.

Scroll

Name	Description
scrollUp()	Scroll the screen up by count lines.
scrollDown()	Scroll the screen down by count lines.
scrollLeft()	Scroll the screen left by count columns.
scrollRight()	Scroll the screen right by count columns.

Text

• stripVTControlCharacters(): Remove all VT control characters. Use to estimate displayed string width.
• getTextTruncatedWidth(): Get the width of a string when truncated to fit within a given width.
• getTextWidth(): Get the width of a string.
• wrapAnsi(): Wrap a string to fit within a given width.
• styleText(): Generate a string with ANSI escape codes for styling.

Style Text

final text = styleText('Hello, World!', [TextStyle.red, TextStyle.bold]);

License

MIT License