double.rb in rdf-0.2.3

- old
+ new

@@ -1,9 +1,15 @@
 module RDF; class Literal
   ##
   # An floating point number literal.
   #
+  # @example Arithmetic with floating point literals
+  #   RDF::Literal(1.0) + 0.5                 #=> RDF::Literal(1.5)
+  #   RDF::Literal(3.0) - 6                   #=> RDF::Literal(-3.0)
+  #   RDF::Literal(Math::PI) * 2              #=> RDF::Literal(Math::PI * 2)
+  #   RDF::Literal(Math::PI) / 2              #=> RDF::Literal(Math::PI / 2)
+  #
   # @see   http://www.w3.org/TR/xmlschema-2/#double
   # @since 0.2.1
   class Double < Literal
     DATATYPE = XSD.double
     GRAMMAR  = /^[\+\-]?\d+(\.\d*([eE][\+\-]?\d+)?)?$/.freeze # FIXME: support 'INF', '-INF' and 'NaN'
@@ -41,9 +47,168 @@
           f = '0' if f.empty?         # ...but there must be a digit to the right of the decimal point
           e.sub!(/^\+?0+(\d)$/, '\1') # remove the optional leading '+' sign and any extra leading zeroes
           "#{i}.#{f}E#{e}"
       end unless @object.nil?
       self
+    end
+
+    ##
+    # Returns `true` if the value is an invalid IEEE floating point number.
+    #
+    # @example
+    #   RDF::Literal(-1.0).nan?           #=> false
+    #   RDF::Literal(1.0/0.0).nan?        #=> false
+    #   RDF::Literal(0.0/0.0).nan?        #=> true
+    #
+    # @return [Boolean]
+    # @since  0.2.3
+    def nan?
+      to_f.nan?
+    end
+
+    ##
+    # Returns `true` if the value is a valid IEEE floating point number (it
+    # is not infinite, and `nan?` is `false`).
+    #
+    # @example
+    #   RDF::Literal(-1.0).finite?        #=> true
+    #   RDF::Literal(1.0/0.0).finite?     #=> false
+    #   RDF::Literal(0.0/0.0).finite?     #=> false
+    #
+    # @return [Boolean]
+    # @since  0.2.3
+    def finite?
+      to_f.finite?
+    end
+
+    ##
+    # Returns `nil`, `-1`, or `+1` depending on whether the value is finite,
+    # `-INF`, or `+INF`.
+    #
+    # @example
+    #   RDF::Literal(0.0/0.0).infinite?   #=> nil
+    #   RDF::Literal(-1.0/0.0).infinite?  #=> -1
+    #   RDF::Literal(+1.0/0.0).infinite?  #=> 1
+    #
+    # @return [Integer]
+    # @since  0.2.3
+    def infinite?
+      to_f.infinite?
+    end
+
+    ##
+    # Returns the smallest integer greater than or equal to `self`.
+    #
+    # @example
+    #   RDF::Literal(1.2).ceil            #=> RDF::Literal(2)
+    #   RDF::Literal(-1.2).ceil           #=> RDF::Literal(-1)
+    #   RDF::Literal(2.0).ceil            #=> RDF::Literal(2)
+    #   RDF::Literal(-2.0).ceil           #=> RDF::Literal(-2)
+    #
+    # @return [RDF::Literal]
+    # @since  0.2.3
+    def ceil
+      RDF::Literal(to_f.ceil)
+    end
+
+    ##
+    # Returns the largest integer less than or equal to `self`.
+    #
+    # @example
+    #   RDF::Literal(1.2).floor           #=> RDF::Literal(1)
+    #   RDF::Literal(-1.2).floor          #=> RDF::Literal(-2)
+    #   RDF::Literal(2.0).floor           #=> RDF::Literal(2)
+    #   RDF::Literal(-2.0).floor          #=> RDF::Literal(-2)
+    #
+    # @return [RDF::Literal]
+    # @since  0.2.3
+    def floor
+      RDF::Literal(to_f.floor)
+    end
+
+    ##
+    # Returns the absolute value of `self`.
+    #
+    # @return [RDF::Literal]
+    # @since  0.2.3
+    def abs
+      (f = to_f) && f > 0 ? self : RDF::Literal(f.abs)
+    end
+
+    ##
+    # Returns `true` if the value is zero.
+    #
+    # @return [Boolean]
+    # @since  0.2.3
+    def zero?
+      to_f.zero?
+    end
+
+    ##
+    # Returns `self` if the value is not zero, `nil` otherwise.
+    #
+    # @return [Boolean]
+    # @since  0.2.3
+    def nonzero?
+      to_f.nonzero? ? self : nil
+    end
+
+    ##
+    # Returns `self`.
+    #
+    # @return [RDF::Literal]
+    # @since  0.2.3
+    def +@
+      self # unary plus
+    end
+
+    ##
+    # Returns `self` negated.
+    #
+    # @return [RDF::Literal]
+    # @since  0.2.3
+    def -@
+      RDF::Literal(-to_f) # unary minus
+    end
+
+    ##
+    # Returns the sum of `self` plus `other`.
+    #
+    # @param  [#to_f] other
+    # @return [RDF::Literal]
+    # @since  0.2.3
+    def +(other)
+      RDF::Literal(to_f + other.to_f)
+    end
+
+    ##
+    # Returns the difference of `self` minus `other`.
+    #
+    # @param  [#to_f] other
+    # @return [RDF::Literal]
+    # @since  0.2.3
+    def -(other)
+      RDF::Literal(to_f - other.to_f)
+    end
+
+    ##
+    # Returns the product of `self` times `other`.
+    #
+    # @param  [#to_f] other
+    # @return [RDF::Literal]
+    # @since  0.2.3
+    def *(other)
+      RDF::Literal(to_f * other.to_f)
+    end
+
+    ##
+    # Returns the quotient of `self` divided by `other`.
+    #
+    # @param  [#to_f] other
+    # @return [RDF::Literal]
+    # @since  0.2.3
+    def /(other)
+      RDF::Literal(to_f / other.to_f)
     end
 
     ##
     # Returns the value as a string.
     #