`class Option`

Represents a single command-line option.

An option is a flag-based argument that can have various forms (short, long, with or without values).

Definitions

`def initialize(flags, description, key: nil, default: nil, value: nil, type: nil, required: false, &block)`

Initialize a new option.

Signature

parameter　flags　String: The flags specification (e.g., -f/--flag <value>).
parameter　description　String: A description of the option for help output.
parameter　key　Symbol | Nil: The key to use for storing the value (defaults to derived from flag).
parameter　default　Object: The default value if the option is not provided.
parameter　value　Object | Nil: A fixed value to use regardless of user input.
parameter　type　Class | Proc | Nil: The type to coerce the value to.
parameter　required　Boolean: Whether the option is required.
yields　{|value| ...}: An optional block to transform the parsed value.

Implementation

def initialize(flags, description, key: nil, default: nil, value: nil, type: nil, required: false, &block)
	@flags = Flags.new(flags)
	@description = description
	
	if key
		@key = key
	else
		@key = @flags.first.key
	end
	
	@default = default
	
	# If the value is given, it overrides the user specified input.
	@value = value
	@value ||= true if @flags.boolean?
	
	@type = type
	@required = required
	@block = block
end

`attr :flags`

The flags for this option.

Signature

attribute　Flags

`attr :description`

A description of the option for help output.

Signature

attribute　String

`attr :key`

The key to use for storing the value.

Signature

attribute　Symbol

`attr :default`

The default value if the option is not provided.

Signature

attribute　Object

`attr :value`

A fixed value to use regardless of user input.

Signature

attribute　Object | Nil

`attr :type`

The type to coerce the value to.

Signature

attribute　Class | Proc | Nil

`attr :required`

Whether the option is required.

Signature

attribute　Boolean

`attr :block`

An optional block to transform the parsed value.

Signature

attribute　Proc | Nil

`def coerce_type(result)`

Coerce the result to the specified type.

Signature

parameter　result　Object: The value to coerce.
returns　Object: The coerced value.

Implementation

def coerce_type(result)
	if @type == Integer
		Integer(result)
	elsif @type == Float
		Float(result)
	elsif @type == Symbol
		result.to_sym
	elsif @type.respond_to? :call
		@type.call(result)
	elsif @type.respond_to? :new
		@type.new(result)
	end
end

`def coerce(result)`

Coerce and transform the result.

Signature

parameter　result　Object: The value to coerce and transform.
returns　Object: The coerced and transformed value.

Implementation

def coerce(result)
	if @type
		result = coerce_type(result)
	end
	
	if @block
		result = @block.call(result)
	end
	
	return result
end

`def parse(input, parent = nil, default = nil)`

Parse this option from the input.

Signature

parameter　input　Array(String): The command-line arguments.
parameter　parent　Command | Nil: The parent command (unused, kept for compatibility).
parameter　default　Object | Nil: An override for the default value (unused, kept for compatibility).
returns　Object | Nil: The parsed value.

Implementation

def parse(input, parent = nil, default = nil)
	result = @flags.parse(input)
	
	if result != nil
		@value.nil? ? coerce(result) : @value
	end
end

`def to_s`

Generate a string representation for usage output.

Signature

returns　String: The usage string.

Implementation

def to_s
	@flags
end

`def to_a`

Generate an array representation for usage output.

Signature

returns　Array: The usage array.

Implementation

def to_a
	if @default
		[@flags, @description, "(default: #{@default})"]
	elsif @required
		[@flags, @description, "(required)"]
	else
		[@flags, @description]
	end
end