Simple Prompt

this is a simple prompt library for ruby. inspired by golang’s huh! library’s input component. https://github.com/charmbracelet/huh

if sombody need it I would make select, multi-select, confirm, text, libraly in addition. But my use case I need input is only needed, so I made input only

Requirements

• Ruby 3.4+
• Bundler

Installation

bash git clone <this-repo> cd simple-input bundle install

or

bash gem install simple-input

Usage Basic Input

```ruby require_relative ‘input’

name = Input.new_input .title(‘What is your name?’) .prompt(‘> ‘) .validate(:not_empty) .run

puts “Hello, #{name}!” ```

Custom Prompt

ruby email = Input.new_input .title('Enter your email') .prompt('email> ') .validate { |val| val.include?('@') ? nil : 'Please enter a valid email' } .run

Multiple Validators

Validators run in order. The first error found is displayed.

ruby password = Input.new_input .title('Create a password') .prompt('password> ') .validate(:not_empty) .validate { |val| val.length < 8 ? 'Must be at least 8 characters' : nil } .run

Custom Validator Provider

By default, symbol validators (e.g., :not_empty) resolve against DefaultValidators. You can swap in your own module with with_validators:

```ruby module MyValidators module_function

def email(val) val.match?(/\A[^@\s]+@[^@\s]+\z/) ? nil : ‘Invalid email format’ end

def min_length(val) val.length >= 3 ? nil : ‘Must be at least 3 characters’ end end

username = Input.new_input .with_validators(MyValidators) .validate(:min_length) .run ```

Validation Types

You can pass validators in three ways:

Type Example Symbol .validate(:not_empty) - looks up method on the validator provider Proc/Lambda .validate(-> (val) { val.empty? ? 'required' : nil }) Block .validate { \|val\| val.empty? ? 'required' : nil }

Validators are functions that take a String and return nil (valid) or an error message String.

Signal Handling

• Ctrl-C - Prints (canceled) and exits gracefully
• Ctrl-D (EOF) - Returns an empty string

API Method Description Input.new_input Factory method to create a new Input (.new is private) #title(text) Set the title displayed above the prompt #prompt(text) Set the prompt string (default: "> ") #validate(validator, &block) Add a validator (Symbol, Proc, or block) #with_validators(provider) Set a custom validator provider module #run Start the interactive input loop and return the result

All methods (except #run) return self for chaining.

Running Examples

bash ruby examples/basic.rb ruby examples/custom_validators.rb

Testing

bash bundle exec rspec

Testing with with_context (Private Method)

The Input class has a private method with_context(reader, writer) that allows injecting custom IO objects for testing. Since new is also private (enforcing use of Input.new_input), tests use send to access with_context:

```ruby def build_input(input_text) reader = StringIO.new(input_text) writer = StringIO.new input = Input.new_input input.send(:with_context, reader, writer) [input, writer] end

Usage in tests

it ‘returns the user input’ do input, = build_input(“hello\n”) result = input.run expect(result).to eq(‘hello’) end

it ‘shows validation errors’ do input, writer = build_input(“\nhello\n”) result = input.validate(:not_empty).run expect(result).to eq(‘hello’) expect(writer.string).to include(‘入力してください’) end ```

This pattern lets you: - Simulate user input via StringIO as the reader - Capture all terminal output via StringIO as the writer - Test the full input loop including validation re-prompting without interactive terminal input

License

MIT