Module: Duration::Common

Includes:
Comparable
Included in:
Days, Hours, Microseconds, Milliseconds, Minutes, Months, Nanoseconds, Seconds, Weeks
Defined in:
lib/Duration/Common.rb

Instance Method Summary collapse

Instance Method Details

#*(other) ⇒ Object

A duration times a number is a duration. A duration times a duration would be time squared, which has no unit here and few enough anywhere, so it is refused rather than quietly given some plausible answer.



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# File 'lib/Duration/Common.rb', line 19

def *(other)
  if other.is_a?(Duration::Common)
    raise TypeError, "can't multiply #{self.class} by #{other.class}: there is no unit of time squared"
  end
  scale(:*, other)
end

#+(other) ⇒ Object 



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# File 'lib/Duration/Common.rb', line 8

def +(other)
  combine(:+, other)
end

#-(other) ⇒ Object 



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# File 'lib/Duration/Common.rb', line 12

def -(other)
  combine(:-, other)
end

#/(other) ⇒ Object

Divided by a number a duration stays a duration. Divided by a duration it becomes the dimensionless ratio of the two, the units having cancelled, which is how a rate or a speedup is arrived at.



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# File 'lib/Duration/Common.rb', line 29

def /(other)
  return ratio(other) if other.is_a?(Duration::Common)
  scale(:quo, other)
end

#<=>(other) ⇒ Object 



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# File 'lib/Duration/Common.rb', line 34

def <=>(other)
  return nil unless other.is_a?(Duration::Common)
  quantity <=> other.send(:"to_#{unit}").quantity
end

#inspect ⇒ Object

The class and the quantity as it is actually held, after measurand: to_s is what a reader wants and inspect is what the object is. It is the one place the difference between an Integer 45 and a Rational 45/1 shows, which in a library this careful about exactness is worth being able to see.



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# File 'lib/Duration/Common.rb', line 53

def inspect
  "#{self.class}(#{quantity.inspect})"
end

#to_s ⇒ Object

The unit is the class, so naming it says which duration this is without repeating the class: 45 days rather than #<Duration::Days:0x000... The quantity is rendered as it is held, an exact Rational staying exact, this library manufacturing no precision it was not given and discarding none it was.



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# File 'lib/Duration/Common.rb', line 44

def to_s
  "#{rendered_quantity} #{quantity == 1 ? unit.to_s.chomp('s') : unit}"
end