Contents

class Measured::UnitSystem
  attr_reader :units

  def initialize(units)
    @units = units.map { |unit| unit.with_unit_system(self) }
  end

  def unit_names_with_aliases
    @unit_names_with_aliases ||= @units.flat_map(&:names).sort
  end

  def unit_names
    @unit_names ||= @units.map(&:name).sort
  end

  def unit_or_alias?(name)
    !!unit_for(name)
  end

  def unit?(name)
    unit = unit_for(name)
    unit ? unit.name == name.to_s : false
  end

  def unit_for(name)
    unit_name_to_unit[name.to_s]
  end

  def unit_for!(name)
    unit = unit_for(name)
    raise Measured::UnitError, "Unit '#{name}' does not exist" unless unit
    unit
  end

  def convert(value, from:, to:)
    conversion = conversion_table.fetch(from.name, {})[to.name]

    raise Measured::UnitError, "Cannot find conversion entry from #{from} to #{to}" unless conversion

    value.to_r * conversion
  end

  protected

  def conversion_table
    @conversion_table ||= Measured::ConversionTable.build(@units)
  end

  def unit_name_to_unit
    @unit_name_to_unit ||= @units.inject({}) do |hash, unit|
      unit.names.each { |name| hash[name.to_s] = unit }
      hash
    end
  end
end

Version data entries

7 entries across 7 versions & 1 rubygems

Version	Path
measured-2.3.0	lib/measured/unit_system.rb
measured-2.2.0	lib/measured/unit_system.rb
measured-2.1.0	lib/measured/unit_system.rb
measured-2.0.0	lib/measured/unit_system.rb
measured-2.0.0.pre4	lib/measured/unit_system.rb
measured-2.0.0.pre3	lib/measured/unit_system.rb
measured-2.0.0.pre2	lib/measured/unit_system.rb