Class: Conversions::Unit

Inherits:
Object
  • Object
show all
Defined in:
lib/conversions/unit.rb

Overview

Proxy class to contain the unit as well as reference the base value

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(value, from) ⇒ Unit

Create a new Unit instance.

  • value: The value to convert from (ie. 4.92)

  • from: The unit to convert from (ie. :miles)



8
9
10
11
 
# File 'lib/conversions/unit.rb', line 8

def initialize(value, from)
  @value = value
  @from = from
end

Class Method Details

.exchange_rate(from_unit_name, to_unit_name) ⇒ Object

:nodoc:

Raises:

  • (ArgumentError) 


38
39
40
41
42
43
44
45
 
# File 'lib/conversions/unit.rb', line 38

def self.exchange_rate(from_unit_name, to_unit_name) #:nodoc:
  return 1 if from_unit_name == to_unit_name
  from = Conversions.conversions[from_unit_name]
  raise ArgumentError, "[conversions] No unit named `#{from_unit_name}'" if from.blank?
  to = from[to_unit_name]
  raise ArgumentError, "[conversions] No exchange rate defined from `#{from_unit_name}' to `#{to_unit_name}'" if to.blank?
  to
end

Instance Method Details

#to(to, options = {}) ⇒ Object

Convert to a certain other unit.

  • to: The unit to convert to (ie. :kilometers)

  • options:

    • :scale: The number of digits behind the decimal point to you want to keep



26
27
28
29
30
31
32
33
34
35
36
 
# File 'lib/conversions/unit.rb', line 26

def to(to, options={})
  case options
  when Integer
    scale = options
  when Hash
    scale = options[:scale]
  end
  
  value = @value * self.class.exchange_rate(@from, to)
  scale.nil? ? value : (value * (10 ** scale)).round / (10 ** scale).to_f
end

#to_f ⇒ Object 



17
18
19
 
# File 'lib/conversions/unit.rb', line 17

def to_f
  @value.to_f
end

#to_i ⇒ Object 



13
14
15
 
# File 'lib/conversions/unit.rb', line 13

def to_i
  @value.to_i
end