Class: Rational

Inherits:
Numeric show all
Defined in:
opal/opal/corelib/rational.rb

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Numeric

#%, #+@, #-@, #__coerced__, #abs2, #angle, #clone, #conj, #div, #divmod, #dup, #fdiv, #finite?, #i, #imag, #infinite?, #integer?, #negative?, #nonzero?, #polar, #positive?, #real, #real?, #rect, #step, #to_c, #to_int, #zero?

Methods included from Comparable

#<, #<=, #>, #>=, #between?, #clamp

Constructor Details

#initialize(num, den) ⇒ Rational

Returns a new instance of Rational.

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# File 'opal/opal/corelib/rational.rb', line 51

def initialize(num, den)
  @num = num
  @den = den
  freeze
end

Class Method Details

.convert(num, den) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 25

def self.convert(num, den)
  if num.nil? || den.nil?
    ::Kernel.raise ::TypeError, 'cannot convert nil into Rational'
  end

  if ::Integer === num && ::Integer === den
    return reduce(num, den)
  end

  if ::Float === num || ::String === num || ::Complex === num
    num = num.to_r
  end

  if ::Float === den || ::String === den || ::Complex === den
    den = den.to_r
  end

  if den.equal?(1) && !(::Integer === num)
    ::Opal.coerce_to!(num, ::Rational, :to_r)
  elsif ::Numeric === num && ::Numeric === den
    num / den
  else
    reduce(num, den)
  end
end

.from_string(string) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 354

def self.from_string(string)
  %x{
    var str = string.trimLeft(),
        re = /^[+-]?[\d_]+(\.[\d_]+)?/,
        match = str.match(re),
        numerator, denominator;

    function isFloat() {
      return re.test(str);
    }

    function cutFloat() {
      var match = str.match(re);
      var number = match[0];
      str = str.slice(number.length);
      return number.replace(/_/g, '');
    }

    if (isFloat()) {
      numerator = parseFloat(cutFloat());

      if (str[0] === '/') {
        // rational real part
        str = str.slice(1);

        if (isFloat()) {
          denominator = parseFloat(cutFloat());
          return #{::Kernel.Rational(`numerator`, `denominator`)};
        } else {
          return #{::Kernel.Rational(`numerator`, 1)};
        }
      } else {
        return #{::Kernel.Rational(`numerator`, 1)};
      }
    } else {
      return #{::Kernel.Rational(0, 1)};
    }
  }
end

.reduce(num, den) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 7

def self.reduce(num, den)
  num = num.to_i
  den = den.to_i

  if den == 0
    ::Kernel.raise ::ZeroDivisionError, 'divided by 0'
  elsif den < 0
    num = -num
    den = -den
  elsif den == 1
    return new(num, den)
  end

  gcd = num.gcd(den)

  new(num / gcd, den / gcd)
end

Instance Method Details

#*(other) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 148

def *(other)
  case other
  when ::Rational
    num = @num * other.numerator
    den = @den * other.denominator

    ::Kernel.Rational(num, den)

  when ::Integer
    ::Kernel.Rational(@num * other, @den)

  when ::Float
    to_f * other

  else
    __coerced__ :*, other
  end
end

#**(other) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 190

def **(other)
  case other
  when ::Integer
    if self == 0 && other < 0
      ::Float::INFINITY
    elsif other > 0
      ::Kernel.Rational(@num**other, @den**other)
    elsif other < 0
      ::Kernel.Rational(@den**-other, @num**-other)
    else
      ::Kernel.Rational(1, 1)
    end

  when ::Float
    to_f**other

  when ::Rational
    if other == 0
      ::Kernel.Rational(1, 1)
    elsif other.denominator == 1
      if other < 0
        ::Kernel.Rational(@den**other.numerator.abs, @num**other.numerator.abs)
      else
        ::Kernel.Rational(@num**other.numerator, @den**other.numerator)
      end
    elsif self == 0 && other < 0
      ::Kernel.raise ::ZeroDivisionError, 'divided by 0'
    else
      to_f**other
    end

  else
    __coerced__ :**, other
  end
end

#+(other) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 110

def +(other)
  case other
  when ::Rational
    num = @num * other.denominator + @den * other.numerator
    den = @den * other.denominator

    ::Kernel.Rational(num, den)

  when ::Integer
    ::Kernel.Rational(@num + other * @den, @den)

  when ::Float
    to_f + other

  else
    __coerced__ :+, other
  end
end

#-(other) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 129

def -(other)
  case other
  when ::Rational
    num = @num * other.denominator - @den * other.numerator
    den = @den * other.denominator

    ::Kernel.Rational(num, den)

  when ::Integer
    ::Kernel.Rational(@num - other * @den, @den)

  when ::Float
    to_f - other

  else
    __coerced__ :-, other
  end
end

#/(other) ⇒ Object Also known as: divide, quo

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# File 'opal/opal/corelib/rational.rb', line 167

def /(other)
  case other
  when ::Rational
    num = @num * other.denominator
    den = @den * other.numerator

    ::Kernel.Rational(num, den)

  when ::Integer
    if other == 0
      to_f / 0.0
    else
      ::Kernel.Rational(@num, @den * other)
    end

  when ::Float
    to_f / other

  else
    __coerced__ :/, other
  end
end

#<=>(other) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 94

def <=>(other)
  case other
  when ::Rational
    @num * other.denominator - @den * other.numerator <=> 0

  when ::Integer
    @num - @den * other <=> 0

  when ::Float
    to_f <=> other

  else
    __coerced__ :<=>, other
  end
end

#==(other) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 78

def ==(other)
  case other
  when ::Rational
    @num == other.numerator && @den == other.denominator

  when ::Integer
    @num == other && @den == 1

  when ::Float
    to_f == other

  else
    other == self
  end
end

#abs ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 226

def abs
  ::Kernel.Rational(@num.abs, @den.abs)
end

#ceil(precision = 0) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 230

def ceil(precision = 0)
  if precision == 0
    (-(-@num / @den)).ceil
  else
    with_precision(:ceil, precision)
  end
end

#coerce(other) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 65

def coerce(other)
  case other
  when ::Rational
    [other, self]

  when ::Integer
    [other.to_r, self]

  when ::Float
    [other, to_f]
  end
end

#denominator ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 61

def denominator
  @den
end

#floor(precision = 0) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 238

def floor(precision = 0)
  if precision == 0
    (-(-@num / @den)).floor
  else
    with_precision(:floor, precision)
  end
end

#hash ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 246

def hash
  [::Rational, @num, @den].hash
end

#inspect ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 250

def inspect
  "(#{self})"
end

#numerator ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 57

def numerator
  @num
end

#rationalize(eps = undefined) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 254

def rationalize(eps = undefined)
  %x{
    if (arguments.length > 1) {
      #{::Kernel.raise ::ArgumentError, "wrong number of arguments (#{`arguments.length`} for 0..1)"};
    }

    if (eps == null) {
      return self;
    }

    var e = #{eps.abs},
        a = #{self - `e`},
        b = #{self + `e`};

    var p0 = 0,
        p1 = 1,
        q0 = 1,
        q1 = 0,
        p2, q2;

    var c, k, t;

    while (true) {
      c = #{`a`.ceil};

      if (#{`c` <= `b`}) {
        break;
      }

      k  = c - 1;
      p2 = k * p1 + p0;
      q2 = k * q1 + q0;
      t  = #{1 / (`b` - `k`)};
      b  = #{1 / (`a` - `k`)};
      a  = t;

      p0 = p1;
      q0 = q1;
      p1 = p2;
      q1 = q2;
    }

    return #{::Kernel.Rational(`c * p1 + p0`, `c * q1 + q0`)};
  }
end

#round(precision = 0) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 300

def round(precision = 0)
  return with_precision(:round, precision) unless precision == 0
  return 0 if @num == 0
  return @num if @den == 1

  num = @num.abs * 2 + @den
  den = @den * 2

  approx = (num / den).truncate

  if @num < 0
    -approx
  else
    approx
  end
end

#to_f ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 317

def to_f
  @num / @den
end

#to_i ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 321

def to_i
  truncate
end

#to_r ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 325

def to_r
  self
end

#to_s ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 329

def to_s
  "#{@num}/#{@den}"
end

#truncate(precision = 0) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 333

def truncate(precision = 0)
  if precision == 0
    @num < 0 ? ceil : floor
  else
    with_precision(:truncate, precision)
  end
end

#with_precision(method, precision) ⇒ Object

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# File 'opal/opal/corelib/rational.rb', line 341

def with_precision(method, precision)
  ::Kernel.raise ::TypeError, 'not an Integer' unless ::Integer === precision

  p = 10**precision
  s = self * p

  if precision < 1
    (s.send(method) / p).to_i
  else
    ::Kernel.Rational(s.send(method), p)
  end
end