Sandbox shell library for Ruby

Overview

The sandbox shell library provides a simple interface for creating a REPL (Read/Eval/Print/Loop) CLI (command line interface)

Installation

Add to your Gemfile:

gem 'sandbox-ruby'

And install it:

bundle install

Or install it manually:

bundle install sandbox-ruby

Primitives

There are a few primitives:

Shell is the main class

Context provides a hierarchical structure for your CLI (like directories in the filesystem)

Command is the endpoint for your commands

Navigation in the CLI

/ Go to root context

.. Go to parent context

../.. Go to parent context by 2 levels down

/fruit/apple Executes command apple in the context fruit

/vegetable/tasty Go to context tasty

Built-in commands

There are built-in commands:

help ? Prints all commands and their descriptions in the current context

path Prints current path

quit exit Quits the CLI

Example

require 'sandbox'

# Create a new shell instance
shell = Sandbox::Shell.new(
  prompt: ' CLI> ',
  banner: 'Example banner',
  # You can disable built-in commands
  # builtin_help: false,
  # builtin_path: false,
  # builtin_quit: false
)

# Command in the root context
command_counter = shell.add_command(
  :counter,
  description: 'Counter',
  params: ['<n>'] # Mandatory parameter
) do |tokens, shell, context, command|
  n = tokens[1].to_i
  n.times { |i| shell.print("#{i + 1} ") }
  shell.puts
end

# Auto completion for the command
command_counter.completion do |shell, tokens, line|
  (1..10).to_a.map(&:to_s)
end

# Any command in the root context can be global (visible in any context)
shell.add_command(
  :echo,
  description: 'Echo',
  params: ['[text]'], # Optional parameter
  global: true
) do |tokens, shell, context, command|
  shell.puts(tokens[1..].join(' '))
end

# Additional context in the root context
context_fruit = shell.add_context(:fruit, description: 'Fruits')
context_fruit.add_command(
  :apple,
  description: 'Apple'
) do |tokens, shell, context, command|
  shell.puts("I'm and apple!")
end

# You can define aliases for your command
context_fruit.add_command(
  :orange,
  description: 'Orange or tangerine',
  aliases: [:tangerine]
) do |tokens, shell, context, command|
  shell.puts("Sometimes i'm an orange or a tangerine")
end

# You can use search path for context and command
shell.add_context(:vegetable, description: 'Vegetables')
shell.context(:vegetable).add_context(:tasty)
shell.context(:vegetable, :tasty).add_command(:potato) do |tokens, shell, context, command|
  shell.puts('Yammy!')
end
shell.command(:vegetable, :tasty, :potato).completion do |line, tokens, shell, context, command|
  %w[one two]
end

# You can remove a context or command at any time
shell.add_context(:useless)
shell.context(:useless).add_command(:test)
shell.context(:useless).remove_command(:test)
shell.remove_context(:useless)

# The confirmation
shell.add_command(:confirm) do |tokens, shell, context, command|
  answer = shell.confirm('Do you confirm it?')
  shell.puts(answer ? 'Yes' : 'No')
end

# Run the shell
shell.run

License

See the LICENSE file