Add RDF::Literal::Numberic#** and RDF::Literal::Numeric#% based on XPath definitions.

Author: gkellogg

lib/rdf/model/literal/numeric.rb

@@ -123,6 +123,40 @@ def *(other)
       end
     end
 
+    ##
+    # Exponent − Performs exponential (power) calculation on operators.
+    #
+    # If other is an instance of xs:integer, the result is self raised to the power of other as defined in the [IEEE 754-2008] specification of the pown function applied to a 64-bit binary floating point value and an integer.
+    #
+    # Otherwise $y is converted to an xs:double by numeric promotion, and the result is the value of $x raised to the power of $y as defined in the [IEEE 754-2008] specification of the pow function applied to two 64-bit binary floating point values.
+    #
+    # @param  [Literal::Numeric, #to_i, #to_f, #to_d] other
+    # @return [RDF::Literal::Double]
+    # @since  0.2.3
+    # @see https://www.w3.org/TR/xpath-functions/#func-math-pow
+    def **(other)
+      RDF::Literal::Double.new(to_f ** other.to_f)
+    end
+
+    ##
+    # Exponent − Performs remainder of `self` divided by `other`.
+    #
+    # @param  [Literal::Numeric, #to_i, #to_f, #to_d] other
+    # @return [RDF::Literal]
+    # @since  0.2.3
+    # @see https://www.w3.org/TR/xpath-functions/#func-numeric-mod
+    def %(other)
+      if self.class == Double || [Double, ::Float].include?(other.class)
+        self.class.new(to_f % other.to_f)
+      elsif ((self.class == RDF::Literal::Float || other.class == RDF::Literal::Float) rescue false)
+        self.class.new(to_f % other.to_f)
+      elsif self.class == Decimal || other.class == Decimal
+        self.class.new(to_d % (other.respond_to?(:to_d) ? other.to_d : BigDecimal(other.to_s)))
+      else
+        self.class.new(to_i % other.to_i)
+      end
+    end
+
     ##
     # Returns the quotient of `self` divided by `other`.
     #

spec/model_literal_spec.rb

@@ -467,6 +467,41 @@ def self.literals(*selector)
         end
       end
     end
+
+    describe "#**" do
+      {
+        "2^3": [2, 3, 8.0e0],
+        "-2^3": [-2, 3, -8.0e0],
+        "2^-3": [2, -3, 0.125e0],
+        "-2^-3": [-2, -3, -0.125e0],
+        "2^0": [2, 0, 1.0e0],
+        "0^0": [0, 0, 1.0e0],
+        "0^4": [0, 4, 0.0e0],
+        "0^-4": [0, -4, RDF::Literal::Double.new('INF')],
+        "16^0.5e0": [16, 0.5e0, 4.0e0],
+        "16^0.25e0": [16, 0.25e0, 2.0e0],
+        "-1^INF": [-1, RDF::Literal::Double.new('INF'), 1.0e0],
+        "-1^-INF": [-1, RDF::Literal::Double.new('-INF'), 1.0e0],
+        "1^INF": [1, RDF::Literal::Double.new('INF'), 1.0e0],
+        "1^-INF": [1, RDF::Literal::Double.new('-INF'), 1.0e0],
+        "1^-NaN": [1, RDF::Literal::Double.new('NaN'), 1.0e0],
+      }.each do |name, (n, e, result)|
+        it name do
+          expect(RDF::Literal(n) ** RDF::Literal(e)).to eq RDF::Literal(result)
+        end
+      end
+    end
+
+    describe "#%" do
+      {
+        "10 % 3": [10, 3, 1],
+        "6 % -2": [6, -2, 0],
+      }.each do |name, (n, e, result)|
+        it name do
+          expect(RDF::Literal(n) % RDF::Literal(e)).to eq RDF::Literal(result)
+        end
+      end
+    end
   end
 
   describe RDF::Literal::Decimal do
@@ -529,6 +564,16 @@ def self.literals(*selector)
         end
       end
     end
+
+    describe "#%" do
+      {
+        "4.5 % 1.2": [RDF::Literal::Decimal.new("4.5"), RDF::Literal::Decimal.new("1.2"), RDF::Literal::Decimal.new("0.9")],
+      }.each do |name, (n, e, result)|
+        it name do
+          expect(RDF::Literal(n) % RDF::Literal(e)).to eq RDF::Literal(result)
+        end
+      end
+    end
   end
 
   describe RDF::Literal::Double do
@@ -689,6 +734,36 @@ def self.literals(*selector)
       expect(inf + nan).to be_nan
       expect(nan + nan).to be_nan
     end
+
+    describe "#**" do
+      {
+        "INF^0": [RDF::Literal::Double.new('INF'), 0, 1.0e0],
+        "NaN^0": [RDF::Literal::Double.new('NaN'), 0, 1.0e0],
+        "0e0^3": [0e0, 3, 0.0e0],
+        "0e0^4": [0e0, 4, 0.0e0],
+        "-0e0^3": [-0e0, 3, -0.0e0],
+        "0e0^-3": [0e0, -3, RDF::Literal::Double.new('INF')],
+        "0e0^-4": [0e0, -4, RDF::Literal::Double.new('INF')],
+        "-0e0^-3": [-0e0, -3, RDF::Literal::Double.new('-INF')],
+        "-0e0^-3.0e0": [-0e0, -3.0e0, RDF::Literal::Double.new('-INF')],
+        "0e0^-3.1e0": [0e0, -3.1e0, RDF::Literal::Double.new('INF')],
+        "-0e0^-3.1e0": [-0e0, -3.1e0, RDF::Literal::Double.new('INF')],
+      }.each do |name, (n, e, result)|
+        it name do
+          expect(RDF::Literal(n) ** RDF::Literal(e)).to eq RDF::Literal(result)
+        end
+      end
+    end
+
+    describe "#%" do
+      {
+        "0e0 % 3": [1.23e2, 0.6e1, 3.0e0],
+      }.each do |name, (n, e, result)|
+        it name do
+          expect(RDF::Literal(n) % RDF::Literal(e)).to eq RDF::Literal(result)
+        end
+      end
+    end
   end
 
   describe RDF::Literal::DateTime do