Class: Fraction

Inherits:
ValueAdd show all
Defined in:
lib/primitive_wrapper.rb

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from ValueAdd

bestow_methods, capture_base_methods

Methods inherited from Value

#!=, #==, #ensure_valid, #freeze, freeze_raise?, ignore_on_freeze, #inspect, #prim_value, raise_on_freeze, #to_wrapper, #type, #type_of?, #unwrap, #val, #val=, #wrapped?, #~

Constructor Details

#initialize(*prms) ⇒ Fraction

Returns a new instance of Fraction.



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# File 'lib/primitive_wrapper.rb', line 755

def initialize(*prms)
  #obj = obj.prim_value
  #ensure_valid(obj)
  #@value = obj
  if 1==prms.count
    @value = Rational(prms[0].prim_value)
  elsif 2==prms.count
    if prms[0].type_of? Float
      if prms[1].type_of? Integer
        sign = prms[0].negative? ? -1:1
        num = prms[0].abs
        whole = num.floor
        frac = num-whole
        num = (frac * prms[1]).round
        frac = Fraction.new(whole, num, prms[1]) * sign
        @value = frac.prim_value
      else
        fract = self.class.approximate_by_float(prms[0].prim_value,prms[1].prim_value)
        @value = fract.prim_value
      end
    else
      @value = Rational(prms[0].prim_value,prms[1].prim_value)
    end
    
  elsif 3==prms.count
    @value = Rational(prms[1].prim_value,prms[2].prim_value) + prms[0].prim_value
  else
    raise("expected 1..3 parameters")
  end
end

Class Method Details

.approximate_by_float(p1, pcnt = nil) ⇒ Object 



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# File 'lib/primitive_wrapper.rb', line 728

def self.approximate_by_float(p1, pcnt=nil)
  return Fraction.new(p1.prim_value) if pcnt.nil?
  pcnt/= 100.0
  neg = p1.negative?
  p1=p1.abs
  if p1 >=1.0
    top = p1.floor
    bot = 1
  else
    top = 1
    bot = (1/p1).floor
  end
  loop do
    app = top.to_f/bot.to_f
    tst = (app - p1).abs/p1
    break if tst < pcnt
    if app > p1
      bot += 1
    else
      top += 1
    end        
  end
  frac = Fraction.new(top.prim_value,bot.prim_value)
  frac = -frac if neg
  return frac
end

Instance Method Details

#%(other) ⇒ Object 



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# File 'lib/primitive_wrapper.rb', line 816

def %(other)
  Fraction.new(@value % other)
end

#*(other) ⇒ Object 



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# File 'lib/primitive_wrapper.rb', line 808

def *(other)
  Fraction.new(@value * other)
end

#**(other) ⇒ Object 



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# File 'lib/primitive_wrapper.rb', line 812

def **(other)
  Fraction.new(@value ** other)
end

#+(other) ⇒ Object 



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# File 'lib/primitive_wrapper.rb', line 800

def +(other)
  Fraction.new(@value + other)
end

#+@ ⇒ Object 



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# File 'lib/primitive_wrapper.rb', line 824

def +@
  Fraction.new(@value)
end

#-(other) ⇒ Object 



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# File 'lib/primitive_wrapper.rb', line 804

def -(other)
  Fraction.new(@value - other)
end

#-@ ⇒ Object 



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# File 'lib/primitive_wrapper.rb', line 828

def -@
  Fraction.new(-@value)
end

#/(other) ⇒ Object 



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# File 'lib/primitive_wrapper.rb', line 820

def /(other)
  Fraction.new(@value / other)
end

#abs! ⇒ Object 



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# File 'lib/primitive_wrapper.rb', line 790

def abs!
  @value = @value.abs
  self
end

#coerce(other) ⇒ Object 



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# File 'lib/primitive_wrapper.rb', line 724

def coerce(other)
  [Fraction.new(other.prim_value), self.prim_value]
end

#negate! ⇒ Object 



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# File 'lib/primitive_wrapper.rb', line 795

def negate!
  @value = -@value.abs
  self
end

#replace(other) ⇒ Object 



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# File 'lib/primitive_wrapper.rb', line 786

def replace(other)    
  @value = Rational(other.prim_value)
end

#to_fraction ⇒ Object 



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# File 'lib/primitive_wrapper.rb', line 832

def to_fraction
  self
end

#to_s(paren = true) ⇒ Object 



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# File 'lib/primitive_wrapper.rb', line 836

def to_s(paren=true)
  return @value.numerator if @value.denominator==1
  if @value.numerator.abs < @value.denominator
    if paren
      return "(#{@value.numerator}/#{@value.denominator})"
    else
      return "#{@value.numerator}/#{@value.denominator}"
    end    
  end    
  if @value.negative?
    rat = -@value
    whole, rem = rat.numerator.divmod rat.denominator
    if paren
      return "(-#{whole} -#{rem}/#{@value.denominator})"
    else
      return "-#{whole} -#{rem}/#{@value.denominator}"
    end
    
  end
  whole, rem = @value.numerator.divmod @value.denominator
  if paren
    return "(#{whole} #{rem}/#{@value.denominator})"
  else
    return "#{whole} #{rem}/#{@value.denominator}"
  end
end

#valid_type(prm) ⇒ Object 



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# File 'lib/primitive_wrapper.rb', line 863

def valid_type(prm)
  return true
end