Class: Adarwin::Interval

Inherits:
Object
  • Object
show all
Defined in:
lib/adarwin/interval.rb

Overview

This class represents an interval [a..b] including a and b. The class has the following methods:

  • Initialise the interval (initialize)

  • Print the interval (to_s)

  • Merge an interval with another interval (merge)

  • Return the length of the interval (length)

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(a, b, loops) ⇒ Interval

Initialise the interval. This method performs a comparison to see whether a or b is the upper-bound. This comparison is based on guesses made by the compare method. This method uses loop information if needed. FIXME: Uses the compare method which might be based on a guess



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# File 'lib/adarwin/interval.rb', line 17

def initialize(a,b,loops)
  @loops = loops
  a = simplify(a.to_s)
  b = simplify(b.to_s)
  case compare(a,b,@loops)
    when 'lt' || 'eq' then @a = a; @b = b
    when 'gt' then @a = b; @b = a
    else @a = a; @b = b
  end
end

Instance Attribute Details

#a ⇒ Object

Returns the value of attribute a.



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# File 'lib/adarwin/interval.rb', line 11

def a
  @a
end

#b ⇒ Object

Returns the value of attribute b.



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# File 'lib/adarwin/interval.rb', line 11

def b
  @b
end

Instance Method Details

#length ⇒ Object

Method to compute the length of the interval. For example, the length of

a..b

is equal to (b-a+1).



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# File 'lib/adarwin/interval.rb', line 52

def length
  simplify("(#{@b})-(#{a})+1")
end

#merge(other_interval) ⇒ Object

Merge this interval with another interval. This is based on a comparison made by the compare method, which is an approximation based on loop information. FIXME: Uses the compare method which might be based on a guess



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# File 'lib/adarwin/interval.rb', line 37

def merge(other_interval)
  @a = case compare(@a,other_interval.a,@loops)
    when 'gt' || 'eq' then other_interval.a
    when 'lt' then @a
    else other_interval.a
  end
  @b = case compare(@b,other_interval.b,@loops)
    when 'gt' || 'eq' then @b
    when 'lt' then other_interval.b
    else @b
  end
end

#to_s ⇒ Object

Print the interval as a string (e.g. [4..9]).



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# File 'lib/adarwin/interval.rb', line 29

def to_s
  @a+RANGE_SEP+@b
end