Contents

require 'csv'
require 'unitwise'

module Eulim
  module Chemistry
    # This class has functionality for elements
    # Ex: symbol, atomic mass, atomic number
    class Element
      attr_accessor :atomic_mass, :symbol, :name, :atomic_number

      ATTRS = %w[symbol name atomic_number atomic_mass].freeze
      # Data taken from 'www.science.co.il/elements/'
      ELEMENTS = []

      def initialize(arg)
        @name = arg[1]
        @symbol = arg[0]
        @atomic_number = arg[2].to_i
        @atomic_mass = Unitwise(arg[3].to_f, 'u')
      end

      # elements of the csv have no spaces
      CSV.foreach(File.join(File.dirname(__FILE__), 'elements.csv'), headers: true) do |row|
        ELEMENTS << new(row)
      end

      private_class_method def self.method_missing(m, *args)
        attribute = m.to_s.split('get_by_').last
        valid_method? m, attribute
        raise 'please give argument' if args.empty?
        args[0] = attribute == 'name' ? args[0].capitalize : args[0]
        element_data = get_element_by_attribute attribute, args[0]
        raise 'Element not found' unless element_data
        element_data
      end

      private_class_method def self.get_element_by_attribute(attribute, value)
        ELEMENTS.each do |element|
          # elements value of attribute == value give by user
          return element if
            element.instance_variable_get(('@' + attribute).intern) == value
        end
        raise(NameError, 'element not found')
      end

      private_class_method def self.valid_method?(m, attribute)
        super unless m.to_s.start_with?('get_by_')
        raise(NameError, 'Invalid attribute') unless ATTRS.include? attribute
      end

      private_class_method :new
    end
  end
end

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
eulim-0.0.11	lib/eulim/chemistry/element.rb