brew/Library/Homebrew/cask/lib/hbc/dsl/installer.rb

module Hbc
  class DSL
    class Installer
      VALID_KEYS = Set.new [
        :manual,
        :script,
      ]

      attr_accessor(*VALID_KEYS)

      def initialize(*parameters)
        raise CaskInvalidError.new(token, "'installer' stanza requires an argument") if parameters.empty?
        parameters = {}.merge(*parameters)
        if parameters.key?(:script) && !parameters[:script].respond_to?(:key?)
          if parameters.key?(:executable)
            raise CaskInvalidError.new(token, "'installer' stanza gave arguments for both :script and :executable")
          end
          parameters[:executable] = parameters[:script]
          parameters.delete(:script)
          parameters = { script: parameters }
        end
        unless parameters.keys.length == 1
          raise "invalid 'installer' stanza: only one of #{VALID_KEYS.inspect} is permitted"
        end
        key = parameters.keys.first
        raise "invalid 'installer' stanza key: '#{key.inspect}'" unless VALID_KEYS.include?(key)
        writer_method = "#{key}=".to_sym
        send(writer_method, parameters[key])
      end
    end
  end
end