# Class: RDF::Literal::Double

Inherits:
Numeric
show all
Defined in:
lib/rdf/model/literal/double.rb

## Overview

An floating point number literal.

Examples:

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)``````

Since:

• 0.2.1

## Constant Summary collapse

DATATYPE =

Since:

• 0.2.1

`RDF::URI("http://www.w3.org/2001/XMLSchema#double")`
GRAMMAR =

Since:

• 0.2.1

`/^(?:NaN|\-?INF|[+\-]?(?:\d+(:?\.\d*)?|\.\d+)(?:[eE][\+\-]?\d+)?)\$/.freeze`
PI =

Approximation of the mathematical constant π

From the XQuery function math:pi.

Returns:

Since:

• 0.2.1

`Double.new(Math::PI)`

## Instance Method Summary collapse

• Compares this literal to `other` for sorting purposes.

• Returns `true` if this literal is equal to `other`.

• Returns the absolute value of `self`.

• Converts this literal into its canonical lexical representation.

• Returns the smallest integer greater than or equal to `self`.

• Returns `true` if the value is a valid IEEE floating point number (it is not infinite, and `nan?` is `false`).

• Returns the largest integer less than or equal to `self`.

• Returns `nil`, `-1`, or `+1` depending on whether the value is finite, `-INF`, or `+INF`.

• constructor

A new instance of Double.

• Returns `true` if the value is an invalid IEEE floating point number.

• Returns `self` if the value is not zero, `nil` otherwise.

• Returns the number with no fractional part that is closest to the argument.

• Returns the value as a string.

• Returns `true` if the value is zero.

## Constructor Details

### #initialize(value, datatype: nil, lexical: nil, **options) ⇒ Double

Returns a new instance of Double.

Parameters:

• value (String, Float, #to_f)
• value (Object)
• language (Symbol)

(nil) Language is downcased to ensure proper matching

• lexical (String) (defaults to: nil)

(nil) Supplied lexical representation of this literal, otherwise it comes from transforming `value` to a string form..

• datatype (URI) (defaults to: nil)

(nil)

• validate (Boolean)

(false)

• canonicalize (Boolean)

(false)

Since:

• 0.2.1

 ``` 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35``` ```# File 'lib/rdf/model/literal/double.rb', line 20 def initialize(value, datatype: nil, lexical: nil, **options) @datatype = RDF::URI(datatype || self.class.const_get(:DATATYPE)) @string = lexical || (value if value.is_a?(String)) @object = case when value.is_a?(::String) then case value.upcase when '+INF' then 1/0.0 when 'INF' then 1/0.0 when '-INF' then -1/0.0 when 'NAN' then 0/0.0 else Float(value.sub(/\.[eE]/, '.0E')) rescue nil end when value.is_a?(::Float) then value when value.respond_to?(:to_f) then value.to_f else 0.0 # FIXME end end```

## Dynamic Method Handling

This class handles dynamic methods through the method_missing method in the class RDF::Literal

## Instance Method Details

### #<=>(other) ⇒ Integer

Compares this literal to `other` for sorting purposes.

Parameters:

• other (Object)

Returns:

• (Integer)

`-1`, `0`, or `1`

Since:

• 0.3.0

 ``` 97 98 99 100 101 102 103 104 105 106 107``` ```# File 'lib/rdf/model/literal/double.rb', line 97 def <=>(other) case other when ::Numeric to_f <=> other when RDF::Literal::Decimal to_f <=> other.to_d when RDF::Literal::Double to_f <=> other.to_f else super end end```

### #==(other) ⇒ Boolean

Returns `true` if this literal is equal to `other`.

Parameters:

• other (Object)

Returns:

• (Boolean)

`true` or `false`

Since:

• 0.3.0

 ``` 82 83 84 85 86 87 88 89``` ```# File 'lib/rdf/model/literal/double.rb', line 82 def ==(other) if valid? && infinite? && other.respond_to?(:infinite?) && other.infinite? infinite? == other.infinite? # JRuby INF comparisons differ from MRI else super end end```

### #abs ⇒ RDF::Literal

Returns the absolute value of `self`.

From the XQuery function fn:abs.

Returns:

Since:

• 0.2.3

 ``` 197 198 199``` ```# File 'lib/rdf/model/literal/double.rb', line 197 def abs (f = to_f) && f > 0 ? self : self.class.new(f.abs) end```

### #canonicalize! ⇒ RDF::Literal

Converts this literal into its canonical lexical representation.

Returns:

• `self`

Since:

• 0.2.1

 ``` 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74``` ```# File 'lib/rdf/model/literal/double.rb', line 50 def canonicalize! # Can't use simple %f transformation due to special requirements from # N3 tests in representation @string = case when @object.nil? then 'NaN' when @object.nan? then 'NaN' when @object.infinite? then @object.to_s[0...-'inity'.length].upcase when @object.zero? then '0.0E0' else i, f, e = ('%.15E' % @object.to_f).split(/[\.E]/) f.sub!(/0*\$/, '') # remove any trailing zeroes f = '0' if f.empty? # ...but there must be a digit to the right of the decimal point e.sub!(/^(?:\+|(\-))?0+(\d+)\$/, '\1\2') # remove the optional leading '+' sign and any extra leading zeroes "#{i}.#{f}E#{e}" end @object = case @string when 'NaN' then 0/0.0 when 'INF' then 1/0.0 when '-INF' then -1/0.0 else Float(@string) end self end```

### #ceil ⇒ RDF::Literal::Integer

Returns the smallest integer greater than or equal to `self`.

From the XQuery function fn:ceil.

Examples:

``````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)``````

Returns:

Since:

• 0.2.3

 ``` 167 168 169``` ```# File 'lib/rdf/model/literal/double.rb', line 167 def ceil RDF::Literal::Integer.new(to_f.ceil) end```

### #finite? ⇒ Boolean

Returns `true` if the value is a valid IEEE floating point number (it is not infinite, and `nan?` is `false`).

Examples:

``````RDF::Literal(-1.0).finite?        #=> true
RDF::Literal(1.0/0.0).finite?     #=> false
RDF::Literal(0.0/0.0).finite?     #=> false``````

Returns:

Since:

• 0.2.3

 ``` 134 135 136``` ```# File 'lib/rdf/model/literal/double.rb', line 134 def finite? to_f.finite? end```

### #floor ⇒ RDF::Literal::Integer

Returns the largest integer less than or equal to `self`.

From the XQuery function fn:floor.

Examples:

``````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)``````

Returns:

Since:

• 0.2.3

 ``` 185 186 187``` ```# File 'lib/rdf/model/literal/double.rb', line 185 def floor RDF::Literal::Integer.new(to_f.floor) end```

### #infinite? ⇒ Integer

Returns `nil`, `-1`, or `+1` depending on whether the value is finite, `-INF`, or `+INF`.

Examples:

``````RDF::Literal(0.0/0.0).infinite?   #=> nil
RDF::Literal(-1.0/0.0).infinite?  #=> -1
RDF::Literal(+1.0/0.0).infinite?  #=> 1``````

Returns:

Since:

• 0.2.3

 ``` 149 150 151``` ```# File 'lib/rdf/model/literal/double.rb', line 149 def infinite? to_f.infinite? end```

### #nan? ⇒ Boolean

Returns `true` if the value is an invalid IEEE floating point number.

Examples:

``````RDF::Literal(-1.0).nan?           #=> false
RDF::Literal(1.0/0.0).nan?        #=> false
RDF::Literal(0.0/0.0).nan?        #=> true``````

Returns:

Since:

• 0.2.3

 ``` 119 120 121``` ```# File 'lib/rdf/model/literal/double.rb', line 119 def nan? to_f.nan? end```

### #nonzero? ⇒ Boolean

Returns `self` if the value is not zero, `nil` otherwise.

Returns:

Since:

• 0.2.3

 ``` 226 227 228``` ```# File 'lib/rdf/model/literal/double.rb', line 226 def nonzero? to_f.nonzero? ? self : nil end```

### #round ⇒ RDF::Literal::Double

Returns the number with no fractional part that is closest to the argument. If there are two such numbers, then the one that is closest to positive infinity is returned. An error is raised if arg is not a numeric value.

From the XQuery function fn:round.

Returns:

Since:

• 0.2.1

 ``` 208 209 210``` ```# File 'lib/rdf/model/literal/double.rb', line 208 def round self.class.new(to_d.round(half: (to_d < 0 ? :down : :up))) end```

### #to_s ⇒ String

Returns the value as a string.

Returns:

Since:

• 0.2.1

 ``` 234 235 236 237 238 239 240``` ```# File 'lib/rdf/model/literal/double.rb', line 234 def to_s @string || case when @object.nan? then 'NaN' when @object.infinite? then @object.to_s[0...-'inity'.length].upcase else @object.to_s end end```

### #zero? ⇒ Boolean

Returns `true` if the value is zero.

Returns:

Since:

• 0.2.3

 ``` 217 218 219``` ```# File 'lib/rdf/model/literal/double.rb', line 217 def zero? to_f.zero? end```