class Option

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.

parameter　completions　Array | Proc | Nil

Completions for option values.

yields　{|value| ...}

An optional block to transform the parsed value.

def initialize(flags, description, key: nil, default: nil, value: nil, type: nil, required: false, completions: nil, &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
	@completions = completions
	@block = block
end

attribute　Flags

attribute　String

attribute　Symbol

returns　Object | Nil

The resolved default value.

def default
	if @default.respond_to?(:call)
		@default.call
	else
		@default
	end
end

returns　Boolean

True if the option has a default value.

def default?
	!@default.nil?
end

attribute　Object | Nil

attribute　Class | Proc | Nil

attribute　Boolean

attribute　Array | Proc | Nil

attribute　Proc | Nil

parameter　token　String

The token to match.

returns　Flag | Nil

The matching flag.

def flag_for(token)
	@flags.flag_for(token)
end

returns　Boolean

True if any flag for this option consumes a value.

def value?
	@flags.any?{|flag| !flag.boolean?}
end

parameter　context　Completion::Context

The completion context.

returns　Completion::Result

The matching option value completions.

def suggestions(context)
	suggestions = []
	context = context.with_row(self)
	
	if default?
		suggestion = Completion::Provider.new(context, [default]).suggestions.first
		
		suggestions << suggestion if suggestion
	end
	
	Completion::Provider.new(context, @completions).suggestions.each do |suggestion|
		suggestions << suggestion unless suggestions.any?{|existing| existing.value == suggestion.value}
	end
	
	Completion::Result.new(suggestions)
end

parameter　result　Object

The value to coerce.

returns　Object

The coerced value.

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

parameter　result　Object

The value to coerce and transform.

returns　Object

The coerced and transformed value.

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

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.

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

returns　String

The usage string.

def to_s
	@flags
end

returns　Array

The usage array.

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