`class Enumeration`

Converts an exact set of input values to corresponding output values.

Definitions

`def self.build(*values, **options)`

Construct an enumeration from accepted values or an input-to-output mapping.

Signature

parameter　values　Array(Object): The accepted values.
parameter　options　Hash: Additional input-to-output mappings.
returns　Enumeration: The enumeration converter.

Implementation

def self.build(*values, **options)
	mapping = values.to_h{|value| [value, value]}
	mapping.update(options)
	return new(mapping)
end

`def initialize(mapping)`

Initialize an enumeration from an input-to-output mapping.

Signature

parameter　mapping　Hash: The accepted inputs and corresponding outputs.

Implementation

def initialize(mapping)
	@mapping = mapping.freeze
end

`attr :mapping`

The accepted input values and corresponding output values.

`def call(value)`

Convert an accepted input value.

Signature

parameter　value　Object: The input value.
returns　Object: The corresponding output value.
raises　ArgumentError: If the input value is not accepted.

Implementation

def call(value)
	if @mapping.key?(value)
		return @mapping[value]
	end
	
	raise ArgumentError, "Invalid enumeration value: #{value.inspect}!"
end