Class: Literal

Inherits:
Object
  • Object
show all
Defined in:
lib/active_rdf/objectmanager/literal.rb

Overview

Represents an RDF literal, optionally datatyped. TODO: language tags

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(value, type_or_language = nil) ⇒ Literal

Constructs literal with given datatype. If no datatype is given, automatic conversion from Ruby to XSD datatype is tried.



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# File 'lib/active_rdf/objectmanager/literal.rb', line 13

def initialize(value, type_or_language=nil)
  @value = value
  
  if type_or_language.nil?
    # deduce type from the given value
    @type = case value
             when String
               XSD::string
             when Date, Time, DateTime
               XSD::date
             when TrueClass, FalseClass
               XSD::boolean
             when Fixnum
               XSD::integer
      end
  elsif type_or_language[0..0] == "@"
    # a language tag has been given
    @language = type_or_language[1..type_or_language.length]
  else
    # the type_or_language was not empty and did not start with a @ so it must be a data type
    @type = type_or_language
  end  

end

Instance Attribute Details

#language ⇒ Object (readonly)

Returns the value of attribute language.



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# File 'lib/active_rdf/objectmanager/literal.rb', line 8

def language
  @language
end

#type ⇒ Object (readonly)

Returns the value of attribute type.



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# File 'lib/active_rdf/objectmanager/literal.rb', line 8

def type
  @type
end

#value ⇒ Object (readonly)

Returns the value of attribute value.



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# File 'lib/active_rdf/objectmanager/literal.rb', line 8

def value
  @value
end

Instance Method Details

#to_s ⇒ Object

returns string serialisation of literal, e.g. “test”^^xsd:string



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# File 'lib/active_rdf/objectmanager/literal.rb', line 39

def to_s
  if type
    "\"#{value}\"^^#{type.to_s}"
  elsif language
    "\"#{value}\"@#{language}"
  else
    "\"value\""
  end
end